Pre-excitation syndrome: Difference between revisions
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{{CMG}} | __NOTOC__ | ||
{{Pre-excitation syndrome}} | |||
{{CMG}} {{AE}} {{Shivam Singla}} | |||
{{ | {{SK}} Pre Excitation [[Syndromes]]; [[Lown-Ganong-Levine syndrome|Lown-Ganong-Levine Syndrome]]; Pre-Excitation, [[Mahaim type preexcitation|Mahaim-Type Pre-excitation]]; [[Wolff-Parkinson-White syndrome|Wolff-Parkinson-White Syndrome]] | ||
==Overview== | |||
== Overview | '''Pre-excitation syndrome''' is a [[condition]] in which the [[ventricles]] of [[heart]] [[depolarize]] earlier than expected via some [[accessory pathway]] [[conduction]], leading to a [[premature contraction]]. Normally, [[atria]] and [[ventricles]] are interconnected with each other via the [[AV node]] ([[atrioventricular node]]). However, in all the [[pre-excitation]] [[syndromes]], an [[accessory]] [[pathway]] is present that [[conducts]] [[impulses]] to [[ventricles]] besides the [[AV node]]. The [[accessory pathway]] passes the [[electrical]] [[impulses]] to the [[ventricles]] before the normal [[impulse]] of [[depolarization]] passes through the [[AV node]]. The phenomenon of [[depolarizing]] [[ventricles]] through the [[accessory pathway]] [[earlier]] than the usual [[depolarization]] is supposed to happen through the [[AV node]] is referred to as [["Pre- Excitation"]]. [[WPW syndrome]] was described in 1930 and named after [[John Parkinson]], [[Paul Dudley White]], and [[Louis Wolff]]. The [[accessory pathways]] are named depending upon the regions of [[atria]] and [[ventricles]] they are connecting such as [[Bundle of His]], [[Mahaim fibers]], and [[James fibers]]. The typical [[ECG]] findings associated with [[WPW syndrome]] are shortened [[PR interval]], [[widened QRS]] complex and [[Delta wave]] which is a slurring in the [[upstroke]] of [[QRS]] complex due to [[preexcitation]] of [[ventricles]] via the [[accessory pathway]]. [[ECG]] findings along with [[symptomatic]] [[tachyarrhythmias]] are referred to as '''[[Wolff-Parkinson-White syndrome]]'''. Although it is more common in [[Adult|adults]], [[males]] have an [[incidence rate]] of 0.1-0.3 %, [[WPW]] can be considered as a [[congenital anomaly]] in some cases where it is usually present since the [[birth]] and in others, it is considered as a [[developmental]] [[anomaly]]. Studies have proven its [[lower]] [[prevalence]] in [[children]] [[aged]] between 6-13 than those in the [[age]] group of 14-15 years of [[age]]. [[Hemodynamically]] [[unstable]] [[patients]] should be managed with a [[direct cardioversion]]. For the stable [[patients]], [[medical]] [[management]] should be used first before using acceptable options of [[catheter ablation]] or [[surgical]] [[intervention]]. Although [[catheter ablation]] has widely replaced the [[surgical]] option, as it is a less [[invasive]] technique with better [[Outcome|outcomes]], in cases where [[catheter]] [[ablation]] cannot be done or doesn't prove to be effective, the [[surgical]] option is worth considering with a [[Cure|curative]] [[rate]] of nearly 100%. | ||
'''Pre-excitation syndrome''' is a condition | |||
==Historical Perspective== | |||
*In 1915, [[Frank Norman Wilson]] became the first to describe the [[condition]] which was later referred to as [[Wolff–Parkinson–White syndrome]]. | |||
*In 1930, [[WPW syndrome]] was first described and named after [[John Parkinson]], [[Paul Dudley White]], and [[Louis Wolff]]. They successfully interpreted a series of 11 [[healthy]] young [[patients]] who had repeated [[Attack rate|attacks]] of [[tachycardia]] in the presence of [[short PR interval]] and [[bundle branch block]] [[pattern]] on the [[ECG]] findings. They also found the [[Association (statistics)|association]] of [[WPW]] with increasing the [[risk]] of [[sudden cardiac death]].<ref>https://doi.org/10.1016/j.eupc.2004.09.005</ref> | |||
*British physiologist "Albert Frank Stanley Kent" (1863 - 1958), first described the lateral branches of [[AV grove]] of the [[monkey]] [[heart]], which were later named as the [[accessory]] [[bundle of Kent]]. | |||
[[File:Wolf-parkinson-white.jpg|thumb|300px|none|WPW Syndrome was given its name in 1930 by Wolf, Parkinson, and White. [https://en.ecgpedia.org/index.php?title=File:Wolffparkinsonwhite.jpg Source: Ecgpedia.org]]] | |||
==Classification== | |||
*Based on the [[Conduction System|conduction]] pathway or [[fiber]] subtype, pre-excitation syndrome may be [[Classification|classified]] into the following sub-types:<ref name="pmid1111564">{{cite journal |vauthors=Lowe KG, Emslie-Smith D, Ward C, Watson H |title=Classification of ventricular pre-excitation. Vectorcardiographic study |journal=Br Heart J |volume=37 |issue=1 |pages=9–19 |date=January 1975 |pmid=1111564 |pmc=484149 |doi=10.1136/hrt.37.1.9 |url=}}</ref><ref name="pmid14563598">{{cite journal| author=Blomström-Lundqvist C, Scheinman MM, Aliot EM, Alpert JS, Calkins H, Camm AJ et al.| title=ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias--executive summary. a report of the American college of cardiology/American heart association task force on practice guidelines and the European society of cardiology committee for practice guidelines (writing committee to develop guidelines for the management of patients with supraventricular arrhythmias) developed in collaboration with NASPE-Heart Rhythm Society. | journal=J Am Coll Cardiol | year= 2003 | volume= 42 | issue= 8 | pages= 1493-531 | pmid=14563598 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=14563598 }} </ref> | |||
{| class="wikitable" | {| class="wikitable" | ||
| | ! style="background: #4479BA; width: 200px;" |{{fontcolor|#FFF|Type}} | ||
| | ! style="background: #4479BA; width: 200px;" |{{fontcolor|#FFF|Conduction pathway}} | ||
| | ! style="background: #4479BA; width: 200px;" |{{fontcolor|#FFF|QRS interval}} | ||
| | ! style="background: #4479BA; width: 200px;" |{{fontcolor|#FFF|PR interval}} | ||
| | ! style="background: #4479BA; width: 200px;" |{{fontcolor|#FFF|Delta wave}} | ||
|- | |- | ||
|[[Wolff-Parkinson-White syndrome]] | | style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Wolff-Parkinson-White syndrome]] | ||
|[[Bundle of Kent]] | |[[Bundle of Kent]] | ||
| | |Wide/long | ||
| | |Usually short | ||
| | |Yes | ||
|- | |- | ||
|[[Lown-Ganong-Levine syndrome]] | | style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Lown-Ganong-Levine syndrome]] | ||
|"James bundle" (atria to bundle of His) | |"[[James fibers|James bundle]]" ([[atria]] to [[bundle of His]]) | ||
| | |Normal/Unaffected | ||
| | |Short | ||
| | |No | ||
|- | |- | ||
|Mahaim-type | | style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Mahaim type preexcitation|Mahaim-type Pre-excitation]] | ||
|[[Mahaim fibers]] | |[[Mahaim fibers]] | ||
| | |Long | ||
| | |Normal | ||
|No | |||
|} | |} | ||
< | *Based on their [[conduction]] properties, following three types of [[accessory pathways]] are there:<ref name="pmid4561817">{{cite journal |vauthors=Kuramoto K, Matsushita S |title=[Classification and interpretation of WPW syndrome] |language=Japanese |journal=Nippon Rinsho |volume=30 |issue=8 |pages=1770–8 |date=August 1972 |pmid=4561817 |doi= |url=}}</ref> | ||
**'''[[Accessory pathway|Manifest Accessory Pathways]]:''' | |||
***[[Conduct|Conducts]] more rapidly as compared to [[AV nodal conduction]]. | |||
***[[Delta waves]] are commonly seen in [[ECG]]. | |||
**'''[[Concealed accessory pathway|Concealed Accessory Pathways]]:''' | |||
***[[Conduct]] in the [[retrograde direction]]. | |||
***As the name represents, the changes in [[ECG]] are [[concealed]] and no [[delta waves]] are seen. | |||
**'''Latent [[Accessory]] Pathways:''' | |||
***These are located in the [[lateral]] part of the [[heart]] as compared to [[AV node]]. | |||
***Hence, the [[impulses]] are delayed in traveling to the [[ventricles]] through the [[AV node]] which is at a much shorter [[distance]] as compared to the [[latent fibers]] located at the farther end. | |||
==Pathophysiology== | |||
===Normal electrical conduction pathway of heart=== | |||
*Normally, the [[electrical]] activity of the [[heart]] starts from [[SA node]]. | |||
*The [[impulse]] [[generation]] usually happens in the right [[atrium]] near the [[entrance]] of [[superior vena cava]] and it travels from [[SA node]] to the [[AV node]]. | |||
*The [[AV node ]] modulates the rate and number of impulses to be conducted to the [[ventricles]]. It also modulates the [[speed]] of [[transmission]] from [[atria]] to [[ventricles]] which represents the [[PR interval]] on ECG. | |||
*From the [[AV node]], an [[electrical]] [[impulse]] is transmitted to the [[bundle of His]], to left and right branches extending to the [[ventricular]] [[myocardium]]. | |||
===Pre-excitation pathway=== | |||
** | *[[WPW]] is another word for [[pre-excitation]] of the [[ventricle]] through the [[accessory]] [[pathway]] instead of going through the usual pathway of [[AV node]] which usually slows down the [[speed]] of [[conduction]] of [[impulses]] transmitted to the [[ventricles]]. | ||
** | *The [[accessory]] pathway creates a channel directly to [[conduct]] the [[impulses]] to [[ventricles]] resulting in a [[premature]] [[excitation]]. | ||
* | *In "Type A [[Pre-excitation]]", the [[accessory]] pathway lies between [[left atria]] and [[ventricles]] whereas in Type B [[Pre-excitation]], [[Fiber|fibers]] carry impulses between [[right atria]] and [[ventricles]]. | ||
** | *Basic [[concept]] of [[pathophysiology]] in pre-excitation syndrome lies in the [[concept]] of [[Bypass|bypassing]] the [[AV node]] [[conduction]] and letting the [[impulse conduct]] faster through [[atria]] to [[ventricles]] via [[accessory pathways]]. | ||
** | *These [[accessory pathways]] usually known as [[Bundle of Kent]] in [[WPW syndrome]], [[James fiber]] in [[LGL syndrome]], and [[Mahaim fibers]] in [[Mahaim type preexcitation|Mahaim type pre-excitation syndrome]]. | ||
** | *These [[conduct]] [[impulses]] in forward (not common), backward (around 15-20%), and in both directions (most common type) as well. | ||
* | *The [[accessory pathways]] mediate the occurrence of [[tachyarrhythmia]] by forming a [[re-entry]] circuit and commonly known as [[AVRT]].<ref name="pmid28328711">{{cite journal |vauthors=Moskowitz A, Chen KP, Cooper AZ, Chahin A, Ghassemi MM, Celi LA |title=Management of Atrial Fibrillation with Rapid Ventricular Response in the Intensive Care Unit: A Secondary Analysis of Electronic Health Record Data |journal=Shock |volume=48 |issue=4 |pages=436–440 |date=October 2017 |pmid=28328711 |pmc=5603354 |doi=10.1097/SHK.0000000000000869 |url=}}</ref> | ||
* | *The direct [[conduction]] of [[impulses]] from [[atria]] to [[ventricles]] can also [[result]] in the [[development]] of [[tachyarrhythmias]] when there is a [[development]] of [[atrial fibrillation]] with [[RVR]]. | ||
*[[WPW syndrome]] is a combination of [[WPW]] [[pattern]] on [[ECG]] plus [[paroxysmal arrhythmias]]. | |||
*The [[accessory pathways]] are usually named as [[Bundle of Kent]] or [[AV node|AV]] [[Bypass tract|bypass tracts]]. | |||
*[[Accessory pathways|The accessory pathways]] here are named as [[James fibers]], also known as [[atrionodal fibers]] connecting the [[atrium (heart)|atrium]] to the distal [[Atrioventricular node|AV node]]. | |||
*These usually [[conduct]] the [[impulses]] from [[atria]] to the initial portion of the [[AV node]]. | |||
*[[Accessory pathways|The accessory pathways]] named as [[Mahaim fibers]] connect the [[atrium (heart)|Atrium]], [[AV node]], or [[bundle of His]] to the [[Purkinje fibers]] or [[ventricular myocardium]]. | |||
==Differentiating Pre-excitation Syndrome from other Diseases== | |||
== Differentiating | |||
* [ | {| class="wikitable" | ||
|+ | |||
! style="background: #4479BA; width: 200px;" |{{fontcolor|#FFF|Arrhythmia}} | |||
! style="background: #4479BA; width: 200px;" |{{fontcolor|#FFF|Rhythm}} | |||
! style="background: #4479BA; width: 200px;" |{{fontcolor|#FFF|Rate}} | |||
! style="background: #4479BA; width: 200px;" |{{fontcolor|#FFF|P wave}} | |||
! style="background: #4479BA; width: 200px;" |{{fontcolor|#FFF|PR Interval}} | |||
! style="background: #4479BA; width: 200px;" |{{fontcolor|#FFF|QRS Complex}} | |||
! style="background: #4479BA; width: 200px;" |{{fontcolor|#FFF|Response to Maneuvers}} | |||
! style="background: #4479BA; width: 200px;" |{{fontcolor|#FFF|Epidemiology}} | |||
! style="background: #4479BA; width: 200px;" |{{fontcolor|#FFF|Co-existing Conditions}} | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Atrial fibrillation|Atrial Fibrillation]] ([[Atrial fibrillation|AFib]])<ref name="pmid22518390">{{cite journal |vauthors=Harris K, Edwards D, Mant J |title=How can we best detect atrial fibrillation? |journal=J R Coll Physicians Edinb |volume=42 Suppl 18 |issue= |pages=5–22 |date=2012 |pmid=22518390 |doi=10.4997/JRCPE.2012.S02 |url=}}</ref><ref name="pmid24837984">{{cite journal |vauthors=Lankveld TA, Zeemering S, Crijns HJ, Schotten U |title=The ECG as a tool to determine atrial fibrillation complexity |journal=Heart |volume=100 |issue=14 |pages=1077–84 |date=July 2014 |pmid=24837984 |doi=10.1136/heartjnl-2013-305149 |url=}}</ref> | |||
| | |||
*[[Irregularly irregular pulse|Irregularly irregular]] | |||
| | |||
*On a 10-[[second]] 12-[[lead]] [[The electrocardiogram|EKG]] strip, multiply the number of [[QRS complexes]] by 6 | |||
| | |||
*Absent | |||
*[[Fibrillation|Fibrillatory waves]] | |||
| | |||
*Absent | |||
| | |||
*Less than 0.12 [[Second|seconds]], consistent, and [[normal]] in [[morphology]] in the absence of [[aberrant]] [[conduction]] | |||
| | |||
*Does not break with [[adenosine]] or [[vagal maneuvers]] | |||
| | |||
*2.7–6.1 million people in the [[United States]] have [[Atrial fibrillation|AFib]] | |||
*2% of people younger than [[age]] 65 have [[Atrial fibrillation|AFib]], while about 9% of people [[Age|aged]] 65 years or older have [[Atrial fibrillation|AFib]] | |||
| | |||
*[[Elderly]] | |||
*Following [[Coronary artery bypass surgery|bypass surgery]] | |||
*[[Mitral valve disease]] | |||
*[[Hyperthyroidism]] | |||
*[[Diabetes mellitus|Diabetes]] | |||
*[[Heart failure]] | |||
*[[Ischemic heart disease]] | |||
*[[Chronic kidney disease]] | |||
*Heavy [[alcohol]] use | |||
*Left chamber enlargement | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |'''[[Atrial Flutter]]'''<ref name="pmid28835836">{{cite journal |vauthors=Cosío FG |title=Atrial Flutter, Typical and Atypical: A Review |journal=Arrhythm Electrophysiol Rev |volume=6 |issue=2 |pages=55–62 |date=June 2017 |pmid=28835836 |pmc=5522718 |doi=10.15420/aer.2017.5.2 |url=}}</ref> | |||
| | |||
*Regular or [[Irregular heart rhythms|Irregular]] | |||
| | |||
*75 (4:1 block), 100 (3:1 block) and 150 (2:1 block) [[Beats per minute|beats per minute (bpm)]], but 150 is more common | |||
| | |||
*Sawtooth [[pattern]] of [[P waves]] at 250 to 350 [[Beats per minute|bpm]] | |||
*[[Biphasic]] deflection in V1 | |||
| | |||
*Varies depending upon the [[Magnitude (mathematics)|magnitude]] of the block, but is short | |||
| | |||
*Less than 0.12 [[Second|seconds]], [[consistent|consistent,]] and [[normal]] in [[morphology]] | |||
| | |||
*[[Conduction]] may vary in response to [[drugs]] and maneuvers dropping the [[rate]] from 150 to 100 or to 75 [[Beats per minute|bpm]] | |||
| | |||
*[[Incidence]]: 88 per 100,000 individuals | |||
| | |||
*[[Elderly]] | |||
*[[Alcohol]] | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |'''[[Atrioventricular nodal reentry tachycardia]] ([[AV nodal reentrant tachycardia|AVNRT]])'''<ref name="pmid20458824">{{cite journal |vauthors=Letsas KP, Weber R, Siklody CH, Mihas CC, Stockinger J, Blum T, Kalusche D, Arentz T |title=Electrocardiographic differentiation of common type atrioventricular nodal reentrant tachycardia from atrioventricular reciprocating tachycardia via a concealed accessory pathway |journal=Acta Cardiol |volume=65 |issue=2 |pages=171–6 |date=April 2010 |pmid=20458824 |doi=10.2143/AC.65.2.2047050 |url=}}</ref><ref name="pmid27617092">{{cite journal |vauthors=Katritsis DG, Josephson ME |title=Classification, Electrophysiological Features and Therapy of Atrioventricular Nodal Reentrant Tachycardia |journal=Arrhythm Electrophysiol Rev |volume=5 |issue=2 |pages=130–5 |date=August 2016 |pmid=27617092 |pmc=5013176 |doi=10.15420/AER.2016.18.2 |url=}}</ref><ref name="pmid25196716">{{cite journal |vauthors=Schernthaner C, Danmayr F, Strohmer B |title=Coexistence of atrioventricular nodal reentrant tachycardia with other forms of arrhythmias |journal=Med Princ Pract |volume=23 |issue=6 |pages=543–50 |date=2014 |pmid=25196716 |pmc=5586929 |doi=10.1159/000365418 |url=}}</ref> | |||
| | |||
*Regular | |||
| | |||
*140-280 [[Beats per minute|bpm]] | |||
| | |||
*[[Slow]]-fast [[AVNRT]]: | |||
**Pseudo-[[S wave]] in [[Lead|leads]] II, III, and AVF | |||
**Pseudo-R' in [[lead]] V1 | |||
*Fast-[[Slow]] [[AVNRT]] | |||
**[[P waves]] between the [[QRS complex|QRS]] and [[T waves]] ([[QRS complex|QRS]]-[[P wave|P]]-[[T wave|T]] complexes) | |||
*[[Slow]]-[[Slow]] [[AVNRT]] | |||
**Late [[P waves]] after a [[QRS complex|QRS]] | |||
**Often appears as [[atrial tachycardia]]. | |||
*[[Invert|Inverted]], superimposed on or buried within the [[QRS complex]] (pseudo [[R wave|R]] prime in V1/pseudo [[S wave]] in inferior [[Lead|leads]]) | |||
| | |||
*Absent ([[P wave]] can appear after the [[QRS complex]] and before the [[T wave]], and in atypical [[AVNRT]], the [[P wave]] can appear just before the [[QRS complex]]) | |||
| | |||
*Less than 0.12 [[Second|seconds]], consistent, and [[normal]] in [[morphology]] in the absence of [[aberrant]] [[conduction]] | |||
*[[QRS complex alternans|QRS alternans]] may be present | |||
| | |||
*May break with [[adenosine]] or [[vagal maneuvers]] | |||
| | |||
*60%-70% of all [[supraventricular tachycardias]] | |||
| | |||
*[[Structural heart disease]] | |||
*[[Atrial tachyarrhythmias]] | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Multifocal atrial tachycardia|Multifocal Atrial Tachycardia]]<ref name="pmid11884328">{{cite journal |vauthors=Goodacre S, Irons R |title=ABC of clinical electrocardiography: Atrial arrhythmias |journal=BMJ |volume=324 |issue=7337 |pages=594–7 |date=March 2002 |pmid=11884328 |pmc=1122515 |doi=10.1136/bmj.324.7337.594 |url=}}</ref><ref name="pmid2570520">{{cite journal |vauthors=Scher DL, Arsura EL |title=Multifocal atrial tachycardia: mechanisms, clinical correlates, and treatment |journal=Am. Heart J. |volume=118 |issue=3 |pages=574–80 |date=September 1989 |pmid=2570520 |doi=10.1016/0002-8703(89)90275-5 |url=}}</ref> | |||
| | |||
*[[Irregular Heart Rhythms|Irregular]] | |||
| | |||
*[[Atrial]] [[rate]] is > 100 [[beats per minute]] | |||
| | |||
*Varying [[morphology]] from at least three different foci | |||
*Absence of one dominant [[atrial]] [[pacemaker]], can be mistaken for [[atrial fibrillation]] if the [[P waves]] are of low [[amplitude]] | |||
| | |||
*Variable [[PR interval|PR intervals]], [[RR intervals]], and [[PP interval|PP intervals]] | |||
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*Less than 0.12 [[Second|seconds]], consistent, and [[normal]] in [[morphology]] | |||
| | |||
*Does not terminate with [[adenosine]] or [[vagal maneuvers]] | |||
| | |||
*0.05% to 0.32% of [[electrocardiograms]] in general [[hospital]] [[Admission note|admissions]] | |||
| | |||
*[[Elderly]] | |||
*[[Chronic obstructive pulmonary disease]] ([[Chronic obstructive pulmonary disease|COPD]]) | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |'''[[Paroxysmal supraventricular tachycardia|Paroxysmal Supraventricular Tachycardia]]''' | |||
| | |||
*Regular | |||
| | |||
*150 and 240 [[Beats per minute|bpm]] | |||
| | |||
*Absent | |||
*Hidden in [[QRS complex|QRS]] | |||
| | |||
*Absent | |||
| | |||
*Narrow [[QRS complexes|complexes]] (< 0.12 [[Second|s]]) | |||
| | |||
*Breaks with [[vagal maneuvers]], [[adenosine]], [[diving reflex]], [[oculocardiac reflex]] | |||
| | |||
*[[Prevalence]]: 0.023 per 100,000 | |||
| | |||
*[[Alcohol]] | |||
*[[Caffeine]] | |||
*[[Nicotine]] | |||
*[[Psychological stress]] | |||
*[[Wolff-Parkinson-White syndrome]] | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |'''[[Premature atrial contraction|Premature Atrial Contractrions]] ([[Premature atrial contraction|PAC]])'''<ref name="pmid18063110">{{cite journal |vauthors=Strasburger JF, Cheulkar B, Wichman HJ |title=Perinatal arrhythmias: diagnosis and management |journal=Clin Perinatol |volume=34 |issue=4 |pages=627–52, vii–viii |date=December 2007 |pmid=18063110 |pmc=3310372 |doi=10.1016/j.clp.2007.10.002 |url=}}</ref><ref name="pmid26316525">{{cite journal |vauthors=Lin CY, Lin YJ, Chen YY, Chang SL, Lo LW, Chao TF, Chung FP, Hu YF, Chong E, Cheng HM, Tuan TC, Liao JN, Chiou CW, Huang JL, Chen SA |title=Prognostic Significance of Premature Atrial Complexes Burden in Prediction of Long-Term Outcome |journal=J Am Heart Assoc |volume=4 |issue=9 |pages=e002192 |date=August 2015 |pmid=26316525 |pmc=4599506 |doi=10.1161/JAHA.115.002192 |url=}}</ref> | |||
| | |||
*Regular except when disturbed by [[premature beat(s)]] | |||
| | |||
*80-120 [[Beats per minute|bpm]] | |||
| | |||
*Upright | |||
| | |||
*> 0.12 [[second]] | |||
*Maybe shorter than that in [[Normal sinus rhythm|normal sinus rhythm (NSR)]] if the [[origin]] of [[PAC]] is located closer to the [[AV node]] | |||
*[[Ashman phenomenon|Ashman’s Phenomenon]]: | |||
**[[Premature atrial contraction|PAC]] displaying a [[right bundle branch block]] [[pattern]] | |||
| | |||
*Usually narrow (< 0.12 [[Second|s]]) | |||
| | |||
*Breaks with [[vagal maneuvers]], [[adenosine]], [[diving reflex]], [[oculocardiac reflex]] | |||
| | |||
| | |||
*[[Infant|Infants]] | |||
*[[Cardiomyopathy]] | |||
*[[Myocarditis]] | |||
*[[Elderly]] | |||
*[[Coronary artery disease]] | |||
*[[Stroke]] | |||
*Increased [[atrial natriuretic peptide]] ([[Atrial natriuretic peptide|ANP]]) | |||
*[[Hypercholesterolemia]] | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Wolff-Parkinson-White syndrome|Wolff-Parkinson-White Syndrome]]<ref name="pmid10597097">{{cite journal |vauthors=Rosner MH, Brady WJ, Kefer MP, Martin ML |title=Electrocardiography in the patient with the Wolff-Parkinson-White syndrome: diagnostic and initial therapeutic issues |journal=Am J Emerg Med |volume=17 |issue=7 |pages=705–14 |date=November 1999 |pmid=10597097 |doi=10.1016/s0735-6757(99)90167-5 |url=}}</ref><ref name="pmid24982705">{{cite journal |vauthors=Rao AL, Salerno JC, Asif IM, Drezner JA |title=Evaluation and management of wolff-Parkinson-white in athletes |journal=Sports Health |volume=6 |issue=4 |pages=326–32 |date=July 2014 |pmid=24982705 |pmc=4065555 |doi=10.1177/1941738113509059 |url=}}</ref> | |||
| | |||
*Regular | |||
| | |||
*[[Atrial]] [[rate]] is nearly 300 [[Beats per minute|bpm]] and the [[ventricular]] [[rate]] is at 150 [[Beats per minute|bpm]] | |||
| | |||
*With [[orthodromic]] [[Conduction System|conduction]] due to a [[bypass tract]], the [[P wave]] generally follows the [[QRS complex]], whereas in [[AVNRT]], the [[P wave]] is generally buried in the [[QRS complex]]. | |||
| | |||
*Less than 0.12 [[Second|seconds]] | |||
| | |||
*A [[delta wave]] and [[evidence]] of [[ventricular]] [[Pre-excitation of the ventricles|pre-excitation]] if there is [[Conduction System|conduction]] to the [[ventricle]] via ante-grade [[conduction]] down an [[accessory pathway]] | |||
*A [[delta wave]] and [[Pre-excitation of the ventricles|pre-excitation]] may not be present because [[Bypass tract|bypass tracts]] do not [[conduct]] ante-grade. | |||
| | |||
*May break in response to [[procainamide]], [[adenosine]], [[vagal maneuvers]] | |||
| | |||
*Worldwide [[prevalence]] of [[Wolff-Parkinson-White syndrome|WPW syndrome]] is 100 - 300 per 100,000 | |||
| | |||
*[[Ebstein's anomaly]] | |||
*[[Mitral valve prolapse]]: This [[cardiac]] [[disorder]], if present, is associated with left-sided [[accessory pathways]]. | |||
*[[Hypertrophic cardiomyopathy]]: This [[disorder]] is associated with [[familial]]/[[inherited]] form of [[Wolff-Parkinson-White syndrome|WPW syndrome]]. | |||
*[[Hypokalemic periodic paralysis]] | |||
*[[Pompe disease]] | |||
*[[Tuberous sclerosis]] | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |'''[[Ventricular fibrillation|Ventricular Fibrillation]] ([[Ventricular fibrillation|VF]])'''<ref name="pmid20142817">{{cite journal |vauthors=Adabag AS, Luepker RV, Roger VL, Gersh BJ |title=Sudden cardiac death: epidemiology and risk factors |journal=Nat Rev Cardiol |volume=7 |issue=4 |pages=216–25 |date=April 2010 |pmid=20142817 |pmc=5014372 |doi=10.1038/nrcardio.2010.3 |url=}}</ref><ref name="pmid27899944">{{cite journal |vauthors=Glinge C, Sattler S, Jabbari R, Tfelt-Hansen J |title=Epidemiology and genetics of ventricular fibrillation during acute myocardial infarction |journal=J Geriatr Cardiol |volume=13 |issue=9 |pages=789–797 |date=September 2016 |pmid=27899944 |pmc=5122505 |doi=10.11909/j.issn.1671-5411.2016.09.006 |url=}}</ref><ref name="pmid11334828">{{cite journal |vauthors=Samie FH, Jalife J |title=Mechanisms underlying ventricular tachycardia and its transition to ventricular fibrillation in the structurally normal heart |journal=Cardiovasc. Res. |volume=50 |issue=2 |pages=242–50 |date=May 2001 |pmid=11334828 |doi=10.1016/s0008-6363(00)00289-3 |url=}}</ref> | |||
| | |||
*[[Irregular heart rhythms|Irregular]] | |||
| | |||
*150 to 500 [[Beats per minute|bpm]] | |||
| | |||
*Absent | |||
| | |||
*Absent | |||
| | |||
*Absent (R on T phenomenon in the setting of [[ischemia]]) | |||
| | |||
*Does not break in response to [[procainamide]], [[adenosine]], [[vagal maneuvers]] | |||
| | |||
*3-12% cases of [[acute myocardial infarction]] (AMI) | |||
*Out of 356,500 out of [[hospital]] [[Cardiac arrest|cardiac arrests]], 23% have [[Ventricular fibrillation|VF]] as initial [[rhythm]] | |||
| | |||
*[[Myocardial ischemia]] / [[Myocardial infarction|infarction]] | |||
*[[Cardiomyopathy]] | |||
*[[Channelopathies]] e.g. [[Long QT Syndrome|Long QT]] ([[acquired]]/ [[congenital]]) | |||
*[[Electrolyte abnormalities]] ([[hypokalemia]]/[[hyperkalemia]], [[hypomagnesemia]]) | |||
*[[Aortic stenosis]] | |||
*[[Aortic dissection]] | |||
*[[Myocarditis]] | |||
*[[Cardiac tamponade]] | |||
*[[Blunt trauma]] (Commotio Cordis) | |||
*[[Sepsis]] | |||
*[[Hypothermia]] | |||
*[[Pneumothorax]] | |||
*[[Seizures]] | |||
*[[Stroke]] | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |'''[[Ventricular tachycardia|Ventricular Tachycardia]]'''<ref name="pmid21505622">{{cite journal |vauthors=Levis JT |title=ECG Diagnosis: Monomorphic Ventricular Tachycardia |journal=Perm J |volume=15 |issue=1 |pages=65 |date=2011 |pmid=21505622 |pmc=3048638 |doi=10.7812/tpp/10-130 |url=}}</ref><ref name="pmid19252119">{{cite journal |vauthors=Koplan BA, Stevenson WG |title=Ventricular tachycardia and sudden cardiac death |journal=Mayo Clin. Proc. |volume=84 |issue=3 |pages=289–97 |date=March 2009 |pmid=19252119 |pmc=2664600 |doi=10.1016/S0025-6196(11)61149-X |url=}}</ref> | |||
| | |||
*Regular | |||
| | |||
*> 100 [[Beats per minute|bpm]] (150-200 [[Beats per minute|bpm]] common) | |||
| | |||
*Absent | |||
| | |||
*Absent | |||
*Initial [[R wave]] in [[V1-morph|V1]], initial r > 40 [[Millisecond|ms]] in [[V1-morph|V1]]/V2, notched [[S wave|S]] in [[V1-morph|V1]], initial [[R wave|R]] in aVR, [[lead]] II [[R wave]] peak time ≥50 [[Millisecond|ms]], no RS in [[V1-morph|V1]]-V6, and [[atrioventricular dissociation]] | |||
| | |||
*Wide complex, [[QRS complex|QRS]] duration > 120 [[Millisecond|milliseconds]] | |||
| | |||
*Does not break in response to [[procainamide]], [[adenosine]], [[vagal maneuvers]] | |||
| | |||
*5-10% of [[patients]] presenting with AMI | |||
| | |||
*[[Coronary artery disease]] | |||
*[[Aortic stenosis]] | |||
*[[Cardiomyopathy]] | |||
*[[Electrolyte imbalance|Electrolyte imbalances]] (e.g., [[hypokalemia]], [[hypomagnesemia]]) | |||
*[[Inherited]] [[channelopathies]] (e.g., [[long-QT syndrome]]) | |||
*[[Catecholaminergic polymorphic ventricular tachycardia]] | |||
*[[Arrhythmogenic right ventricular dysplasia]] | |||
*[[Myocardial infarction]] | |||
*[[Torsades de pointes]] is a form of [[polymorphic VT]] that is often associated with a prolonged [[QT interval]] | |||
|} | |||
== Epidemiology and Demographics | ==Epidemiology and Demographics== | ||
* | *[[WPW]] is commonly found with an [[incidence]] of around 0.1-3.0 per thousand [[population]].<ref name="pmid22579340">{{cite journal |vauthors=Cohen MI, Triedman JK, Cannon BC, Davis AM, Drago F, Janousek J, Klein GJ, Law IH, Morady FJ, Paul T, Perry JC, Sanatani S, Tanel RE |title=PACES/HRS expert consensus statement on the management of the asymptomatic young patient with a Wolff-Parkinson-White (WPW, ventricular preexcitation) electrocardiographic pattern: developed in partnership between the Pediatric and Congenital Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS). Endorsed by the governing bodies of PACES, HRS, the American College of Cardiology Foundation (ACCF), the American Heart Association (AHA), the American Academy of Pediatrics (AAP), and the Canadian Heart Rhythm Society (CHRS) |journal=Heart Rhythm |volume=9 |issue=6 |pages=1006–24 |date=June 2012 |pmid=22579340 |doi=10.1016/j.hrthm.2012.03.050 |url=}}</ref> | ||
* | *More common in the [[male]] [[population]] as compared to [[females]]. | ||
*[[Familial studies]] have found that it is 0.55% more commonly found amoung [[first degree]] relatives. | |||
*More common in [[young]] and [[healthy]] [[individuals|individuals,]] and as the [[age]] advances, the [[prevalence]] of [[disease]] [[decreases]] because of loss of [[pre-excitation]]. | |||
*[[WPW]] can be considered as a [[congenital]] [[anomaly]] in some cases where it is usually present since [[birth]] whereas in others, it is regarded as a [[developmental]] [[anomaly]]. Studies have shown a [[lower]] [[prevalence]] in [[children]] [[aged]] between 6-13 than those in the [[age]] group of 14-15 [[Year|years]] of [[age]]. | |||
== | ==Risk Factors== | ||
* | *High-risk [[population]] for [[development]] of [[atrial fibrillation]] or [[sudden cardiac death]] include:<ref name="pmid22532593">{{cite journal |vauthors=Obeyesekere MN, Leong-Sit P, Massel D, Manlucu J, Modi S, Krahn AD, Skanes AC, Yee R, Gula LJ, Klein GJ |title=Risk of arrhythmia and sudden death in patients with asymptomatic preexcitation: a meta-analysis |journal=Circulation |volume=125 |issue=19 |pages=2308–15 |date=May 2012 |pmid=22532593 |doi=10.1161/CIRCULATIONAHA.111.055350 |url=}}</ref> | ||
**[[Pilots]] | |||
**[[Male]] [[gender]] | |||
**[[Athletes]] | |||
**[[Policemen]] | |||
**[[Steelworkers]] | |||
**[[Firemen]] | |||
**Past history of [[syncope]] | |||
**[[Age]] (peak [[Age|ages]] for the [[development]] of [[atrial fibrillation]] include 30 [[Year|years]] and 50 [[Year|years]]) | |||
==Natural History, Complications, and Prognosis== | |||
===Natural History=== | |||
=== | *Numerous [[studies]] have been published to [[describe]] the [[natural history]] or [[disease]] course of pre-excitation syndrome. [[Data]] from a recent study- "[[Long term]] [[natural]] [[history]] of [[patients]] with [[WPW]] treated with or without [[catheter ablation]]" showed promising [[results]] in explaining the reduced [[long-term]] [[mortality]] rates in [[WPW]] [[patients]] who are matched for [[age]] and [[gender]]. It also explained that there is a lower [[mortality]] rate among [[catheter]] ablated [[patients]] as compared to the non-ablated ones. Although the [[patients]] can die with [[sudden cardiac death]], death is uncommon.<ref name="pmid22532593">{{cite journal |vauthors=Obeyesekere MN, Leong-Sit P, Massel D, Manlucu J, Modi S, Krahn AD, Skanes AC, Yee R, Gula LJ, Klein GJ |title=Risk of arrhythmia and sudden death in patients with asymptomatic preexcitation: a meta-analysis |journal=Circulation |volume=125 |issue=19 |pages=2308–15 |date=May 2012 |pmid=22532593 |doi=10.1161/CIRCULATIONAHA.111.055350 |url=}}</ref> | ||
===Complications=== | |||
* [ | *Most common [[complications]] studied in [[patients]] having [[accessory pathway]] [[Conduction basics|conduction]] are [[arrhythmias]] and [[sudden cardiac death]]. | ||
* | **'''[[Tachyarrhythmias]]:''' | ||
***If there is a [[development]] of [[atrial fibrillation]] or [[flutter]], then there is [[fast conduction]] across the [[tracts]] which leads to an increased risk of dangerous [[ventricular arrhythmias]]. | |||
***[[AV nodal blocks|AV nodal blocking agents]] may also be the factor responsible for the [[increased]] [[Conduction System|conduction]] through [[accessory pathways]] causing life-threatening [[ventricular arrhythmias]] or [[hemodynamic]] instability resulting in a worse [[prognosis]]. | |||
**'''[[Sudden cardiac death]]:''' | |||
***[[Sudden cardiac death]] is a more common [[complication]] in [[patients]] with the following characteristics: | |||
****A young [[male]] with [[age]] less than 35 | |||
****Past history of [[arrhythmias]] | |||
****[[Anatomical|Anatomical location]] of [[accessory pathway]]- that is the [[septal]] [[Location parameter|location]] of the [[accessory pathway]] | |||
****Having multiple [[accessory pathways]] | |||
***The studies proved the risk of [[sudden cardiac death]] related to the pre-excitation syndrome is around 1.5% in [[childhood]] with the highest [[risk]] in the first two decades of [[life]]. | |||
=== | ===Prognosis=== | ||
* | *[[Prognosis]] is usually very good if the [[patient]] is being [[Managed care|managed]] and [[Treatment|treated]] appropriately. | ||
*[[Catheter ablation]] showed promising [[Result|results]] in the [[curative]] [[treatment]] of [[patients]] suffering from this [[disorder]]. | |||
*[[Sudden cardiac death]] is rarely seen in [[patients]] with this [[syndrome]] but when it happens, it is most commonly related to [[arrhythmias]]. | |||
*The most common [[misconception]] about the [[prognosis]] of [[WPW syndrome]] is related to the severity of [[symptoms]] in a [[patient]] but the most important determinant of [[prognosis]] is dependent on the [[electrophysiologic]] properties of the [[accessory pathways]]. | |||
*The [[conduction]] through [[accessory pathways]] usually decreases with [[age]]. This is due to [[fibrotic changes]] that happen with time.<br /> | |||
==Diagnosis== | |||
===WPW Syndrome=== | |||
*[[WPW syndrome]] is a combination of [[WPW]] [[pattern]] on [[ECG]] and paroxysmal [[arrhythmias]]. The [[accessory pathways]] are usually named as [[Bundle of Kent]] or [[AV]] [[bypass tracts]]. | |||
*[[ECG]] [[Features (pattern recognition)|features]] of [[WPW]] syndrome are: | |||
**[[Short PR interval]] <120 ms (<0.12 [[Second|seconds]]) with [[normal]] [[P wave]] [[morphology]] | |||
**[[Wide QRS complexes|Widened QRS complex]] (>0.12 [[Second|seconds]]) | |||
**[[Delta wave]] - slurring upstroke of the initial [[QRS complex]] due to the early and [[rapid depolarization]] of [[ventricles]] (the most important [[criteria]] for the [[diagnosis]] of [[WPW syndrome]]). | |||
**Deflection of [[T waves]] [[opposite]] to the [[direction]] of [[QRS complexes]]/[[secondary]] changes in [[ST-segment]] and [[T wave]] | |||
**Types of [[AVRT]] varies depending on the [[direction]] of the [[impulse conduction]] in the [[re-entry circuit]] ([[orthodromic]] or [[antidromic]]): | |||
***[[Orthodromic AVRT|'''Orthodromic AVRT''']] means the [[antegrade conduction]] is through the [[AV node]] and [[retrograde]] through the [[accessory pathway]]. It presents with [[narrow QRS]] complexes on [[ECG]]. | |||
***[[Antidromic AVRT|'''Antidromic AVRT''']] means the [[antegrade]] [[conduction]] is through the AP and [[retrograde]] conduction through [[AV node]]. It presents with [[Wide QRS complex tachycardias|wide QRS complexes]] on [[ECG]]. | |||
**So in short, the [[Orthodromic AVRT]] [[preexcitation]] [[syndrome]] presents with [[narrow complex tachycardia]] and [[Antodromic AVRT|Antidromic AVRT]] [[pre-excitation]] [[syndrome]] presents with [[wide complex]] [[Tachycardias|tachycardia]]. | |||
**[[AF]] with [[RVR]] can be [[diagnosed]] in [[patients]] with [[WPW]] by comparing it with the baseline [[ECG]]. Look for comparison between [[pre-excited]] [[QRS]] complexes on the baseline [[ECG]] vs those seen during [[irregular tachycardia]]. | |||
**Mainly categorized into 2 subtypes | |||
***Type A - Positive [[delta wave]] | |||
***Type B - Negative [[delta wave]] | |||
[[File:WPW Syndrome - ECG changes with delta wave.png|thumb|300px|none|WPW ECG changes with significant 1) Delta wave 2) PR interval shortening 3) Wide QRS complexes. [https://openi.nlm.nih.gov/detailedresult?img=PMC4944806_wjem-17-469-g002&query=WPW%20syndrome&it=xg&req=4&npos=35]]] | |||
== | ===Lown-Ganong-Levine (LGL) Syndrome=== | ||
* The | *The [[accessory pathways]] [[LGL syndrome]] are named as [[James fibers]], also known as [[atrionodal fibers]] connecting the [[Atrium (heart)|atrium]] to the distal [[Atrioventricular node|AV node]]. These usually [[conduct]] the [[impulses]] from [[atria]] to the initial portion of the [[AV node]]. | ||
*[[ECG]] features: | |||
**[[PR interval]] is less than 120 ms or 0.12 [[Second|seconds]] with [[normal]] [[P wave]] [[morphology]] | |||
**[[Normal]] [[QRS complex]] | |||
* | **Absence of [[Delta wave|delta waves]] | ||
**Episodic [[Paroxysmal supraventricular tachycardia|paroxysmal SVT]] | |||
== | ===Mahaim-Type Pre-excitation=== | ||
=== | *The [[accessory pathways]] named as [[Mahaim fibers]] connect the [[atrium (heart)|atrium]], [[AV node]], or [[bundle of His]] to the [[Purkinje fibers]] or [[ventricular myocardium]].<ref name="pmid15489095">{{cite journal |vauthors=Sternick EB, Timmermans C, Sosa E, Cruz FE, Rodriguez LM, Fagundes MA, Gerken LM, Wellens HJ |title=The electrocardiogram during sinus rhythm and tachycardia in patients with Mahaim fibers: the importance of an "rS" pattern in lead III |journal=J. Am. Coll. Cardiol. |volume=44 |issue=8 |pages=1626–35 |date=October 2004 |pmid=15489095 |doi=10.1016/j.jacc.2004.07.035 |url=}}</ref> | ||
*[[ECG]] findings are usually [[normal]]. | |||
===History and Symptoms=== | |||
:* [ | *[[Patients]] with pre-excitation syndromes maybe [[Asymptomatic|asymptomatic,]] however, they can commonly experience the following [[symptoms]]: | ||
**[[Palpitation|Palpitations]] | |||
**[[Dizziness]] or [[lightheadedness]] | |||
**[[Dyspnea|Shortness of breath]] | |||
**[[Chest pain]] | |||
**[[Fatigue]] | |||
**[[Anxiety]] | |||
**[[Fainting]] | |||
**[[Difficulty breathing]] | |||
=== | ==Treatment== | ||
===Medical Treatment=== | |||
* [ | *'''[[Hemodynamically unstable|HEMODYNAMICALLY UNSTABLE]] [[Patient|PATIENT]]''' -- [[Direct-current cardioversion|DIRECT SYNCHRONIZED CARDIOVERSION]], [[Biphasic|BIPHASIC]] (INITIAL 100 [[Joule|J]], LATER ON- 200[[Joule|J]] OR 360[[Joule|J]]). | ||
* | *'''[[Hemodynamically|HEMODYNAMICALLY]] [[Stability|STABLE]] [[Patient|PATIENT]]''' -- THE FOLLOWING [[Protocols|PROTOCOL]] SHOULD BE FOLLOWED: | ||
====GENERAL PROTOCOL==== | |||
General [[Protocols|protocol]] includes the following:<ref name="pmid30056397">{{cite journal |vauthors=Stasiak A, Niewiadomska-Jarosik K, Kędziora P |title=Clinical course and treatment of children and adolescents with the preexcitation syndrome - own studies |journal=Dev Period Med |volume=22 |issue=2 |pages=113–122 |date=2018 |pmid=30056397 |doi= |url=}}</ref> | |||
: | |||
*[[Antiarrhythmic drug|'''Antiarrhythmic drug''']] | |||
**Helps in slowing the [[accessory pathway]] [[conduction]] and thus plays a major role in the [[Acute|acute events.]] | |||
*'''[[Atrioventricular block|AV Nodal blocking]] agents should NOT be used''' | |||
**As they aggravate [[WPW]] by increasing the [[conduction]] through the [[accessory pathway]]. | |||
*'''Address the underlying [[Causes|cause]] [[Trigger|triggering]] [[dysrhythmias]] which may include:''' | |||
**[[Coronary artery disease]] | |||
**[[Cardiomyopathy]] | |||
**[[Electrolyte abnormalities|Electrolyte derangement]] | |||
**[[Anemia]] | |||
**[[Thyroid disease]] | |||
====IN CASE OF [[ACUTE]] [[AVRT]]/[[AVNRT]]==== | |||
*[[Treatment|Treated]] by [[Blocking (statistics)|blocking]] the [[AV nodal]] [[conduction]] | |||
**Help in [[Blocking (statistics)|blocking]] the [[Pathways Health and Research Centre|pathways]] responsible for causing [[dysrhythmias]] through the involvement of the [[AV node]] ([[AV reentrant tachycardia|AVRT]]/[[AV nodal reentrant tachycardia|AVNRT]]). | |||
**[[Vagal maneuvers|Vagal Maneuvers]] - [[Valsalva maneuver]], immersing the face in [[cold water]] or [[ice water]], [[carotid sinus massage]] | |||
**[[IV]] [[Adenosine]]- very short [[half-life]] and commonly used in [[dose]] around 6-12 mg | |||
**[[IV]] [[Verapamil]]- this is a [[calcium]] [[channel blocker]] and commonly used as 5-10 mg. | |||
=== | ====[[ATRIAL FLUTTER]]/[[FIBRILLATION]]==== | ||
* | *If [[wide complex]] [[tachycardia]] is present:<ref name="pmid23545139">{{cite journal |vauthors=Wann LS, Curtis AB, Ellenbogen KA, Estes NA, Ezekowitz MD, Jackman WM, January CT, Lowe JE, Page RL, Slotwiner DJ, Stevenson WG, Tracy CM, Fuster V, Rydén LE, Cannom DS, Crijns HJ, Curtis AB, Ellenbogen KA, Halperin JL, Le Heuzey J, Kay GN, Lowe JE, Olsson SB, Prystowsky EN, Tamargo JL, Wann LS |title=Management of patients with atrial fibrillation (compilation of 2006 ACCF/AHA/ESC and 2011 ACCF/AHA/HRS recommendations): a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines |journal=Circulation |volume=127 |issue=18 |pages=1916–26 |date=May 2013 |pmid=23545139 |doi=10.1161/CIR.0b013e318290826d |url=}}</ref> | ||
**Use IV [[Amiodarone]] or [[Procainamide|Procainamaide]] | |||
====[[Radiofrequency ablation|RADIOFREQUENCY ABLATION]]==== | |||
=== | *This [[modality]] has replaced [[drug therapy]] and other [[Surgery operation|surgical treatment]] options by showing promising [[Result|results]]. The best [[Result|results]] have been found when it is used in [[Conjunction introduction|conjunction]] with [[cryoblation]] (commonly used for [[accessory pathway|septal accessory pathways]] and for [[accessory pathways]] near small [[coronary arteries]]).<ref name="pmid22579340">{{cite journal |vauthors=Cohen MI, Triedman JK, Cannon BC, Davis AM, Drago F, Janousek J, Klein GJ, Law IH, Morady FJ, Paul T, Perry JC, Sanatani S, Tanel RE |title=PACES/HRS expert consensus statement on the management of the asymptomatic young patient with a Wolff-Parkinson-White (WPW, ventricular preexcitation) electrocardiographic pattern: developed in partnership between the Pediatric and Congenital Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS). Endorsed by the governing bodies of PACES, HRS, the American College of Cardiology Foundation (ACCF), the American Heart Association (AHA), the American Academy of Pediatrics (AAP), and the Canadian Heart Rhythm Society (CHRS) |journal=Heart Rhythm |volume=9 |issue=6 |pages=1006–24 |date=June 2012 |pmid=22579340 |doi=10.1016/j.hrthm.2012.03.050 |url=}}</ref> | ||
*This technique is used widely with best [[Result|results]] in: | |||
**[[Patients]] with [[AVRT]] showing [[symptoms]] of [[dysrhythmias]] | |||
**[[Patients]] with impaired functional [[Activities of daily living|daily activities]] having no [[symptoms]] with ventricular pre-excitation | |||
**[[Patients]] with [[Wolff-Parkinson-White syndrome|WPW]] and [[family history]] of [[sudden cardiac death]] in first or [[second]]-degree relatives. | |||
**[[Patients]] with [[AVRT]] OR [[Atrial fibrillation|A.FIB]] with RVR | |||
**[[Patients]] with H/O pre-excited [[Atrial fibrillation|A.FIB]] | |||
*[[Patients]] who are not willing to undergo [[radiofrequency]] [[ablation]] can be managed on [[medical]] management with the use of [[anti-arrhythmic]]. Though its role in the [[prevention]] of future episodes of [[arrhythmias]] is limited, still this is the most commonly used [[modality]] of choice. | |||
*Class 3 [[Antiarrhythmics]] and class IC [[drugs]] are used with [[Atrioventricular block|AV nodal blocking]] agents in [[patients]] with a history of [[atrial flutter]] or [[Atrial fibrillation|A.Fib]]. | |||
*[[Sotalol]] and [[Flecainide]] are safe options to use in [[pregnancy]]. | |||
===Surgical management=== | |||
* [ | *[[Surgery|Surgical]] management includes the following options: | ||
* | **'''[[Endocardial|ENDOCARDIAL]] [[Surgery|SURGICAL]] [[APPROACH]]''' | ||
* [ | **'''[[Epicardial|EPICARDIAL]] [[Surgery|SURGICAL]] [[APPROACH]]''' | ||
**Due to the [[continuing]] advancement in [[medical]] [[science]], [[radiofrequency catheter ablation]] is widely used as a preferred [[treatment]] option. | |||
**Role of the [[Surgery|surgical]] approach is limited to: | |||
***[[Patients]] who are undergoing [[cardiac surgery]] due to other [[causes]]. | |||
***[[Patients]] in whom [[catheter ablation]] is tried but failed in the past. | |||
***[[Patients]] with multiple [[Area|areas]] or [[foci]] [[Generation|generating]] the [[impulses]] usually requires a [[surgical]] approach for best [[Outcome|outcomes]]. | |||
==Prevention== | |||
*The most common [[preventive]] measures used against [[WPW]] are [[radiofrequency catheter ablation]]. | |||
* [[ | **This [[helps]] in [[preventing]] future [[Attack rate|attacks]] by [[Ablation|ablating]] the [[accessory pathways]] with a success [[rate]] of >95%. | ||
*Although the success [[rate]] for the [[surgical]] approach is 100%, still the [[catheter ablation]] is preferred as it is less [[invasive]] and [[Association (statistics)|associated]] with lower [[complication]] [[rates]]. | |||
*General [[Measure (mathematics)|measures]] that help in [[preventing]] the [[episodes]] such as [[valsalva maneuvers]] should be taught to the [[patient]] so that [[tachycardia]] can be relieved during an [[acute episode]]. | |||
*Although [[medicines]]/[[antiarrhythmic]] can help [[Prevention|prevent]] [[recurrent]] [[episodes]], this is only preferred in [[Patient|patients]] who are not the candidates for [[catheter]] [[ablation]] or [[surgical]] approach. | |||
==References== | |||
{{Reflist|2}} | |||
{{ | |||
[[Category:Cardiology]] | [[Category:Cardiology]] | ||
[[Category:Up TO Date]] | |||
Latest revision as of 13:04, 15 April 2021
Pre-excitation syndrome Microchapters |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2] Associate Editor(s)-in-Chief: Shivam Singla, M.D.[3]
Synonyms and keywords: Pre Excitation Syndromes; Lown-Ganong-Levine Syndrome; Pre-Excitation, Mahaim-Type Pre-excitation; Wolff-Parkinson-White Syndrome
Overview
Pre-excitation syndrome is a condition in which the ventricles of heart depolarize earlier than expected via some accessory pathway conduction, leading to a premature contraction. Normally, atria and ventricles are interconnected with each other via the AV node (atrioventricular node). However, in all the pre-excitation syndromes, an accessory pathway is present that conducts impulses to ventricles besides the AV node. The accessory pathway passes the electrical impulses to the ventricles before the normal impulse of depolarization passes through the AV node. The phenomenon of depolarizing ventricles through the accessory pathway earlier than the usual depolarization is supposed to happen through the AV node is referred to as "Pre- Excitation". WPW syndrome was described in 1930 and named after John Parkinson, Paul Dudley White, and Louis Wolff. The accessory pathways are named depending upon the regions of atria and ventricles they are connecting such as Bundle of His, Mahaim fibers, and James fibers. The typical ECG findings associated with WPW syndrome are shortened PR interval, widened QRS complex and Delta wave which is a slurring in the upstroke of QRS complex due to preexcitation of ventricles via the accessory pathway. ECG findings along with symptomatic tachyarrhythmias are referred to as Wolff-Parkinson-White syndrome. Although it is more common in adults, males have an incidence rate of 0.1-0.3 %, WPW can be considered as a congenital anomaly in some cases where it is usually present since the birth and in others, it is considered as a developmental anomaly. Studies have proven its lower prevalence in children aged between 6-13 than those in the age group of 14-15 years of age. Hemodynamically unstable patients should be managed with a direct cardioversion. For the stable patients, medical management should be used first before using acceptable options of catheter ablation or surgical intervention. Although catheter ablation has widely replaced the surgical option, as it is a less invasive technique with better outcomes, in cases where catheter ablation cannot be done or doesn't prove to be effective, the surgical option is worth considering with a curative rate of nearly 100%.
Historical Perspective
- In 1915, Frank Norman Wilson became the first to describe the condition which was later referred to as Wolff–Parkinson–White syndrome.
- In 1930, WPW syndrome was first described and named after John Parkinson, Paul Dudley White, and Louis Wolff. They successfully interpreted a series of 11 healthy young patients who had repeated attacks of tachycardia in the presence of short PR interval and bundle branch block pattern on the ECG findings. They also found the association of WPW with increasing the risk of sudden cardiac death.[1]
- British physiologist "Albert Frank Stanley Kent" (1863 - 1958), first described the lateral branches of AV grove of the monkey heart, which were later named as the accessory bundle of Kent.
![](/images/e/e6/Wolf-parkinson-white.jpg)
Classification
- Based on the conduction pathway or fiber subtype, pre-excitation syndrome may be classified into the following sub-types:[2][3]
Type | Conduction pathway | QRS interval | PR interval | Delta wave |
---|---|---|---|---|
Wolff-Parkinson-White syndrome | Bundle of Kent | Wide/long | Usually short | Yes |
Lown-Ganong-Levine syndrome | "James bundle" (atria to bundle of His) | Normal/Unaffected | Short | No |
Mahaim-type Pre-excitation | Mahaim fibers | Long | Normal | No |
- Based on their conduction properties, following three types of accessory pathways are there:[4]
- Manifest Accessory Pathways:
- Conducts more rapidly as compared to AV nodal conduction.
- Delta waves are commonly seen in ECG.
- Concealed Accessory Pathways:
- Conduct in the retrograde direction.
- As the name represents, the changes in ECG are concealed and no delta waves are seen.
- Latent Accessory Pathways:
- These are located in the lateral part of the heart as compared to AV node.
- Hence, the impulses are delayed in traveling to the ventricles through the AV node which is at a much shorter distance as compared to the latent fibers located at the farther end.
- Manifest Accessory Pathways:
Pathophysiology
Normal electrical conduction pathway of heart
- Normally, the electrical activity of the heart starts from SA node.
- The impulse generation usually happens in the right atrium near the entrance of superior vena cava and it travels from SA node to the AV node.
- The AV node modulates the rate and number of impulses to be conducted to the ventricles. It also modulates the speed of transmission from atria to ventricles which represents the PR interval on ECG.
- From the AV node, an electrical impulse is transmitted to the bundle of His, to left and right branches extending to the ventricular myocardium.
Pre-excitation pathway
- WPW is another word for pre-excitation of the ventricle through the accessory pathway instead of going through the usual pathway of AV node which usually slows down the speed of conduction of impulses transmitted to the ventricles.
- The accessory pathway creates a channel directly to conduct the impulses to ventricles resulting in a premature excitation.
- In "Type A Pre-excitation", the accessory pathway lies between left atria and ventricles whereas in Type B Pre-excitation, fibers carry impulses between right atria and ventricles.
- Basic concept of pathophysiology in pre-excitation syndrome lies in the concept of bypassing the AV node conduction and letting the impulse conduct faster through atria to ventricles via accessory pathways.
- These accessory pathways usually known as Bundle of Kent in WPW syndrome, James fiber in LGL syndrome, and Mahaim fibers in Mahaim type pre-excitation syndrome.
- These conduct impulses in forward (not common), backward (around 15-20%), and in both directions (most common type) as well.
- The accessory pathways mediate the occurrence of tachyarrhythmia by forming a re-entry circuit and commonly known as AVRT.[5]
- The direct conduction of impulses from atria to ventricles can also result in the development of tachyarrhythmias when there is a development of atrial fibrillation with RVR.
- WPW syndrome is a combination of WPW pattern on ECG plus paroxysmal arrhythmias.
- The accessory pathways are usually named as Bundle of Kent or AV bypass tracts.
- The accessory pathways here are named as James fibers, also known as atrionodal fibers connecting the atrium to the distal AV node.
- These usually conduct the impulses from atria to the initial portion of the AV node.
- The accessory pathways named as Mahaim fibers connect the Atrium, AV node, or bundle of His to the Purkinje fibers or ventricular myocardium.
Differentiating Pre-excitation Syndrome from other Diseases
Epidemiology and Demographics
- WPW is commonly found with an incidence of around 0.1-3.0 per thousand population.[23]
- More common in the male population as compared to females.
- Familial studies have found that it is 0.55% more commonly found amoung first degree relatives.
- More common in young and healthy individuals, and as the age advances, the prevalence of disease decreases because of loss of pre-excitation.
- WPW can be considered as a congenital anomaly in some cases where it is usually present since birth whereas in others, it is regarded as a developmental anomaly. Studies have shown a lower prevalence in children aged between 6-13 than those in the age group of 14-15 years of age.
Risk Factors
- High-risk population for development of atrial fibrillation or sudden cardiac death include:[24]
- Pilots
- Male gender
- Athletes
- Policemen
- Steelworkers
- Firemen
- Past history of syncope
- Age (peak ages for the development of atrial fibrillation include 30 years and 50 years)
Natural History, Complications, and Prognosis
Natural History
- Numerous studies have been published to describe the natural history or disease course of pre-excitation syndrome. Data from a recent study- "Long term natural history of patients with WPW treated with or without catheter ablation" showed promising results in explaining the reduced long-term mortality rates in WPW patients who are matched for age and gender. It also explained that there is a lower mortality rate among catheter ablated patients as compared to the non-ablated ones. Although the patients can die with sudden cardiac death, death is uncommon.[24]
Complications
- Most common complications studied in patients having accessory pathway conduction are arrhythmias and sudden cardiac death.
- Tachyarrhythmias:
- If there is a development of atrial fibrillation or flutter, then there is fast conduction across the tracts which leads to an increased risk of dangerous ventricular arrhythmias.
- AV nodal blocking agents may also be the factor responsible for the increased conduction through accessory pathways causing life-threatening ventricular arrhythmias or hemodynamic instability resulting in a worse prognosis.
- Sudden cardiac death:
- Sudden cardiac death is a more common complication in patients with the following characteristics:
- A young male with age less than 35
- Past history of arrhythmias
- Anatomical location of accessory pathway- that is the septal location of the accessory pathway
- Having multiple accessory pathways
- The studies proved the risk of sudden cardiac death related to the pre-excitation syndrome is around 1.5% in childhood with the highest risk in the first two decades of life.
- Sudden cardiac death is a more common complication in patients with the following characteristics:
- Tachyarrhythmias:
Prognosis
- Prognosis is usually very good if the patient is being managed and treated appropriately.
- Catheter ablation showed promising results in the curative treatment of patients suffering from this disorder.
- Sudden cardiac death is rarely seen in patients with this syndrome but when it happens, it is most commonly related to arrhythmias.
- The most common misconception about the prognosis of WPW syndrome is related to the severity of symptoms in a patient but the most important determinant of prognosis is dependent on the electrophysiologic properties of the accessory pathways.
- The conduction through accessory pathways usually decreases with age. This is due to fibrotic changes that happen with time.
Diagnosis
WPW Syndrome
- WPW syndrome is a combination of WPW pattern on ECG and paroxysmal arrhythmias. The accessory pathways are usually named as Bundle of Kent or AV bypass tracts.
- ECG features of WPW syndrome are:
- Short PR interval <120 ms (<0.12 seconds) with normal P wave morphology
- Widened QRS complex (>0.12 seconds)
- Delta wave - slurring upstroke of the initial QRS complex due to the early and rapid depolarization of ventricles (the most important criteria for the diagnosis of WPW syndrome).
- Deflection of T waves opposite to the direction of QRS complexes/secondary changes in ST-segment and T wave
- Types of AVRT varies depending on the direction of the impulse conduction in the re-entry circuit (orthodromic or antidromic):
- Orthodromic AVRT means the antegrade conduction is through the AV node and retrograde through the accessory pathway. It presents with narrow QRS complexes on ECG.
- Antidromic AVRT means the antegrade conduction is through the AP and retrograde conduction through AV node. It presents with wide QRS complexes on ECG.
- So in short, the Orthodromic AVRT preexcitation syndrome presents with narrow complex tachycardia and Antidromic AVRT pre-excitation syndrome presents with wide complex tachycardia.
- AF with RVR can be diagnosed in patients with WPW by comparing it with the baseline ECG. Look for comparison between pre-excited QRS complexes on the baseline ECG vs those seen during irregular tachycardia.
- Mainly categorized into 2 subtypes
- Type A - Positive delta wave
- Type B - Negative delta wave
![](/images/6/60/WPW_Syndrome_-_ECG_changes_with_delta_wave.png)
Lown-Ganong-Levine (LGL) Syndrome
- The accessory pathways LGL syndrome are named as James fibers, also known as atrionodal fibers connecting the atrium to the distal AV node. These usually conduct the impulses from atria to the initial portion of the AV node.
- ECG features:
- PR interval is less than 120 ms or 0.12 seconds with normal P wave morphology
- Normal QRS complex
- Absence of delta waves
- Episodic paroxysmal SVT
Mahaim-Type Pre-excitation
- The accessory pathways named as Mahaim fibers connect the atrium, AV node, or bundle of His to the Purkinje fibers or ventricular myocardium.[25]
- ECG findings are usually normal.
History and Symptoms
- Patients with pre-excitation syndromes maybe asymptomatic, however, they can commonly experience the following symptoms:
Treatment
Medical Treatment
- HEMODYNAMICALLY UNSTABLE PATIENT -- DIRECT SYNCHRONIZED CARDIOVERSION, BIPHASIC (INITIAL 100 J, LATER ON- 200J OR 360J).
- HEMODYNAMICALLY STABLE PATIENT -- THE FOLLOWING PROTOCOL SHOULD BE FOLLOWED:
GENERAL PROTOCOL
General protocol includes the following:[26]
- Antiarrhythmic drug
- Helps in slowing the accessory pathway conduction and thus plays a major role in the acute events.
- AV Nodal blocking agents should NOT be used
- As they aggravate WPW by increasing the conduction through the accessory pathway.
- Address the underlying cause triggering dysrhythmias which may include:
IN CASE OF ACUTE AVRT/AVNRT
- Treated by blocking the AV nodal conduction
- Help in blocking the pathways responsible for causing dysrhythmias through the involvement of the AV node (AVRT/AVNRT).
- Vagal Maneuvers - Valsalva maneuver, immersing the face in cold water or ice water, carotid sinus massage
- IV Adenosine- very short half-life and commonly used in dose around 6-12 mg
- IV Verapamil- this is a calcium channel blocker and commonly used as 5-10 mg.
ATRIAL FLUTTER/FIBRILLATION
- If wide complex tachycardia is present:[27]
- Use IV Amiodarone or Procainamaide
RADIOFREQUENCY ABLATION
- This modality has replaced drug therapy and other surgical treatment options by showing promising results. The best results have been found when it is used in conjunction with cryoblation (commonly used for septal accessory pathways and for accessory pathways near small coronary arteries).[23]
- This technique is used widely with best results in:
- Patients with AVRT showing symptoms of dysrhythmias
- Patients with impaired functional daily activities having no symptoms with ventricular pre-excitation
- Patients with WPW and family history of sudden cardiac death in first or second-degree relatives.
- Patients with AVRT OR A.FIB with RVR
- Patients with H/O pre-excited A.FIB
- Patients who are not willing to undergo radiofrequency ablation can be managed on medical management with the use of anti-arrhythmic. Though its role in the prevention of future episodes of arrhythmias is limited, still this is the most commonly used modality of choice.
- Class 3 Antiarrhythmics and class IC drugs are used with AV nodal blocking agents in patients with a history of atrial flutter or A.Fib.
- Sotalol and Flecainide are safe options to use in pregnancy.
Surgical management
- Surgical management includes the following options:
- ENDOCARDIAL SURGICAL APPROACH
- EPICARDIAL SURGICAL APPROACH
- Due to the continuing advancement in medical science, radiofrequency catheter ablation is widely used as a preferred treatment option.
- Role of the surgical approach is limited to:
- Patients who are undergoing cardiac surgery due to other causes.
- Patients in whom catheter ablation is tried but failed in the past.
- Patients with multiple areas or foci generating the impulses usually requires a surgical approach for best outcomes.
Prevention
- The most common preventive measures used against WPW are radiofrequency catheter ablation.
- This helps in preventing future attacks by ablating the accessory pathways with a success rate of >95%.
- Although the success rate for the surgical approach is 100%, still the catheter ablation is preferred as it is less invasive and associated with lower complication rates.
- General measures that help in preventing the episodes such as valsalva maneuvers should be taught to the patient so that tachycardia can be relieved during an acute episode.
- Although medicines/antiarrhythmic can help prevent recurrent episodes, this is only preferred in patients who are not the candidates for catheter ablation or surgical approach.
References
- ↑ https://doi.org/10.1016/j.eupc.2004.09.005
- ↑ Lowe KG, Emslie-Smith D, Ward C, Watson H (January 1975). "Classification of ventricular pre-excitation. Vectorcardiographic study". Br Heart J. 37 (1): 9–19. doi:10.1136/hrt.37.1.9. PMC 484149. PMID 1111564.
- ↑ Blomström-Lundqvist C, Scheinman MM, Aliot EM, Alpert JS, Calkins H, Camm AJ; et al. (2003). "ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias--executive summary. a report of the American college of cardiology/American heart association task force on practice guidelines and the European society of cardiology committee for practice guidelines (writing committee to develop guidelines for the management of patients with supraventricular arrhythmias) developed in collaboration with NASPE-Heart Rhythm Society". J Am Coll Cardiol. 42 (8): 1493–531. PMID 14563598.
- ↑ Kuramoto K, Matsushita S (August 1972). "[Classification and interpretation of WPW syndrome]". Nippon Rinsho (in Japanese). 30 (8): 1770–8. PMID 4561817.
- ↑ Moskowitz A, Chen KP, Cooper AZ, Chahin A, Ghassemi MM, Celi LA (October 2017). "Management of Atrial Fibrillation with Rapid Ventricular Response in the Intensive Care Unit: A Secondary Analysis of Electronic Health Record Data". Shock. 48 (4): 436–440. doi:10.1097/SHK.0000000000000869. PMC 5603354. PMID 28328711.
- ↑ Harris K, Edwards D, Mant J (2012). "How can we best detect atrial fibrillation?". J R Coll Physicians Edinb. 42 Suppl 18: 5–22. doi:10.4997/JRCPE.2012.S02. PMID 22518390.
- ↑ Lankveld TA, Zeemering S, Crijns HJ, Schotten U (July 2014). "The ECG as a tool to determine atrial fibrillation complexity". Heart. 100 (14): 1077–84. doi:10.1136/heartjnl-2013-305149. PMID 24837984.
- ↑ Cosío FG (June 2017). "Atrial Flutter, Typical and Atypical: A Review". Arrhythm Electrophysiol Rev. 6 (2): 55–62. doi:10.15420/aer.2017.5.2. PMC 5522718. PMID 28835836.
- ↑ Letsas KP, Weber R, Siklody CH, Mihas CC, Stockinger J, Blum T, Kalusche D, Arentz T (April 2010). "Electrocardiographic differentiation of common type atrioventricular nodal reentrant tachycardia from atrioventricular reciprocating tachycardia via a concealed accessory pathway". Acta Cardiol. 65 (2): 171–6. doi:10.2143/AC.65.2.2047050. PMID 20458824.
- ↑ Katritsis DG, Josephson ME (August 2016). "Classification, Electrophysiological Features and Therapy of Atrioventricular Nodal Reentrant Tachycardia". Arrhythm Electrophysiol Rev. 5 (2): 130–5. doi:10.15420/AER.2016.18.2. PMC 5013176. PMID 27617092.
- ↑ Schernthaner C, Danmayr F, Strohmer B (2014). "Coexistence of atrioventricular nodal reentrant tachycardia with other forms of arrhythmias". Med Princ Pract. 23 (6): 543–50. doi:10.1159/000365418. PMC 5586929. PMID 25196716.
- ↑ Goodacre S, Irons R (March 2002). "ABC of clinical electrocardiography: Atrial arrhythmias". BMJ. 324 (7337): 594–7. doi:10.1136/bmj.324.7337.594. PMC 1122515. PMID 11884328.
- ↑ Scher DL, Arsura EL (September 1989). "Multifocal atrial tachycardia: mechanisms, clinical correlates, and treatment". Am. Heart J. 118 (3): 574–80. doi:10.1016/0002-8703(89)90275-5. PMID 2570520.
- ↑ Strasburger JF, Cheulkar B, Wichman HJ (December 2007). "Perinatal arrhythmias: diagnosis and management". Clin Perinatol. 34 (4): 627–52, vii–viii. doi:10.1016/j.clp.2007.10.002. PMC 3310372. PMID 18063110.
- ↑ Lin CY, Lin YJ, Chen YY, Chang SL, Lo LW, Chao TF, Chung FP, Hu YF, Chong E, Cheng HM, Tuan TC, Liao JN, Chiou CW, Huang JL, Chen SA (August 2015). "Prognostic Significance of Premature Atrial Complexes Burden in Prediction of Long-Term Outcome". J Am Heart Assoc. 4 (9): e002192. doi:10.1161/JAHA.115.002192. PMC 4599506. PMID 26316525.
- ↑ Rosner MH, Brady WJ, Kefer MP, Martin ML (November 1999). "Electrocardiography in the patient with the Wolff-Parkinson-White syndrome: diagnostic and initial therapeutic issues". Am J Emerg Med. 17 (7): 705–14. doi:10.1016/s0735-6757(99)90167-5. PMID 10597097.
- ↑ Rao AL, Salerno JC, Asif IM, Drezner JA (July 2014). "Evaluation and management of wolff-Parkinson-white in athletes". Sports Health. 6 (4): 326–32. doi:10.1177/1941738113509059. PMC 4065555. PMID 24982705.
- ↑ Adabag AS, Luepker RV, Roger VL, Gersh BJ (April 2010). "Sudden cardiac death: epidemiology and risk factors". Nat Rev Cardiol. 7 (4): 216–25. doi:10.1038/nrcardio.2010.3. PMC 5014372. PMID 20142817.
- ↑ Glinge C, Sattler S, Jabbari R, Tfelt-Hansen J (September 2016). "Epidemiology and genetics of ventricular fibrillation during acute myocardial infarction". J Geriatr Cardiol. 13 (9): 789–797. doi:10.11909/j.issn.1671-5411.2016.09.006. PMC 5122505. PMID 27899944.
- ↑ Samie FH, Jalife J (May 2001). "Mechanisms underlying ventricular tachycardia and its transition to ventricular fibrillation in the structurally normal heart". Cardiovasc. Res. 50 (2): 242–50. doi:10.1016/s0008-6363(00)00289-3. PMID 11334828.
- ↑ Levis JT (2011). "ECG Diagnosis: Monomorphic Ventricular Tachycardia". Perm J. 15 (1): 65. doi:10.7812/tpp/10-130. PMC 3048638. PMID 21505622.
- ↑ Koplan BA, Stevenson WG (March 2009). "Ventricular tachycardia and sudden cardiac death". Mayo Clin. Proc. 84 (3): 289–97. doi:10.1016/S0025-6196(11)61149-X. PMC 2664600. PMID 19252119.
- ↑ 23.0 23.1 Cohen MI, Triedman JK, Cannon BC, Davis AM, Drago F, Janousek J, Klein GJ, Law IH, Morady FJ, Paul T, Perry JC, Sanatani S, Tanel RE (June 2012). "PACES/HRS expert consensus statement on the management of the asymptomatic young patient with a Wolff-Parkinson-White (WPW, ventricular preexcitation) electrocardiographic pattern: developed in partnership between the Pediatric and Congenital Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS). Endorsed by the governing bodies of PACES, HRS, the American College of Cardiology Foundation (ACCF), the American Heart Association (AHA), the American Academy of Pediatrics (AAP), and the Canadian Heart Rhythm Society (CHRS)". Heart Rhythm. 9 (6): 1006–24. doi:10.1016/j.hrthm.2012.03.050. PMID 22579340.
- ↑ 24.0 24.1 Obeyesekere MN, Leong-Sit P, Massel D, Manlucu J, Modi S, Krahn AD, Skanes AC, Yee R, Gula LJ, Klein GJ (May 2012). "Risk of arrhythmia and sudden death in patients with asymptomatic preexcitation: a meta-analysis". Circulation. 125 (19): 2308–15. doi:10.1161/CIRCULATIONAHA.111.055350. PMID 22532593.
- ↑ Sternick EB, Timmermans C, Sosa E, Cruz FE, Rodriguez LM, Fagundes MA, Gerken LM, Wellens HJ (October 2004). "The electrocardiogram during sinus rhythm and tachycardia in patients with Mahaim fibers: the importance of an "rS" pattern in lead III". J. Am. Coll. Cardiol. 44 (8): 1626–35. doi:10.1016/j.jacc.2004.07.035. PMID 15489095.
- ↑ Stasiak A, Niewiadomska-Jarosik K, Kędziora P (2018). "Clinical course and treatment of children and adolescents with the preexcitation syndrome - own studies". Dev Period Med. 22 (2): 113–122. PMID 30056397.
- ↑ Wann LS, Curtis AB, Ellenbogen KA, Estes NA, Ezekowitz MD, Jackman WM, January CT, Lowe JE, Page RL, Slotwiner DJ, Stevenson WG, Tracy CM, Fuster V, Rydén LE, Cannom DS, Crijns HJ, Curtis AB, Ellenbogen KA, Halperin JL, Le Heuzey J, Kay GN, Lowe JE, Olsson SB, Prystowsky EN, Tamargo JL, Wann LS (May 2013). "Management of patients with atrial fibrillation (compilation of 2006 ACCF/AHA/ESC and 2011 ACCF/AHA/HRS recommendations): a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines". Circulation. 127 (18): 1916–26. doi:10.1161/CIR.0b013e318290826d. PMID 23545139.