|
|
| Line 19: |
Line 19: |
|
| |
|
| ==[[Pulseless ventricular tachycardia classification|Classification]]== | | ==[[Pulseless ventricular tachycardia classification|Classification]]== |
| [[Pulseless ventricular tachycardia]] as a [[ventricular tachycardia]], may be classified based on the [[morphology]] of the [[QRS complexes]] into two subtypes/groups: [[monomorphic ventricular tachycardia]], and [[polymorphic ventricular tachycardia]].
| | <br /> |
|
| |
|
| ==[[Pulseless ventricular tachycardia pathophysiology|Pathophysiology]]== | | ==[[Pulseless ventricular tachycardia pathophysiology|Pathophysiology]]== |
|
| |
|
| Rapid abnormal [[automaticity]] and [[triggered activity]] are thought to be the main [[electrophysiological]] mechanisms of [[pulseless ventricular tachycardia]]. In abnormal automatically, the ventricular myocytes produce strong, voluntary, and recurrent depolarization and subsequent contractions at a rate that is higher than normal. This is due to a due to a decrease (ranging between -70mV and -30mV) in normal [[resting membrane potential]]. The higher the reduction in [[membrane potential]], the faster and more rapid the already abnormal [[automaticity]].<ref name="pmid4237287">{{cite journal |vauthors=Armendares S, Pérez Treviño C |title=[Congenital heart diseases in chromosome abnormalities. I. In Down's syndrome (mongolism)] |language=Spanish; Castilian |journal=Arch Inst Cardiol Mex |volume=38 |issue=6 |pages=779–91 |date=1968 |pmid=4237287 |doi= |url=}}</ref> Triggered activity is used to depict the indication of impulse in cardiac myocytes that is dependent on [[afterdepolarizations]] (an oscillation in membrane potential that occurs after repolarization). Two types of afterdepolarizations have been identified: [[Early afterdepolarizations]](EAD) and [[Delayed afterdepolarizations]] (DAD). When either of these afterdepolarizations become high enough to reach the [[membrane threshold]], they result in a spontaneous "triggered" action potential. Hence for a triggered activity to occur, at least one action potential must precede it.<ref name="pmid1855225">{{cite journal |vauthors=Buchmann A, Ruggeri B, Klein-Szanto AJ, Balmain A |title=Progression of squamous carcinoma cells to spindle carcinomas of mouse skin is associated with an imbalance of H-ras alleles on chromosome 7 |journal=Cancer Res. |volume=51 |issue=15 |pages=4097–101 |date=August 1991 |pmid=1855225 |doi= |url=}}</ref>
| | <br /> |
| | |
| In pulseless ventricular tachycardia, the combination of increased automatically and/or triggered activity leads to a rate of contraction that is too rapid to result in adequate ventricular filling during diastole. This results in deficient cardiac output, inadequate perfusion of organs, and hemodynamic collapse.<ref name="pmid32119354">{{cite journal |vauthors=Foglesong A, Mathew D |title= |journal= |volume= |issue= |pages= |date= |pmid=32119354 |doi= |url=}}</ref>
| |
|
| |
|
| ==[[Pulseless ventricular tachycardia causess|Causes/Risk Factors]]== | | ==[[Pulseless ventricular tachycardia causess|Causes/Risk Factors]]== |
| [[Structural heart disease]] is the most common cause of [[pulseless ventricular tachycardia]]. Other causes include but are not limited to, drugs/medications, [[congenital heart diseases]], not to mention congenital and inherited [[channelopathies]]. It is important to note that [[QT interval]] lengthening medications, as well as [[electrolyte]] disturbances, can also result in pulseless ventricular tachycardia.<ref name="pmid27484660">{{cite journal |vauthors=Baldzizhar A, Manuylova E, Marchenko R, Kryvalap Y, Carey MG |title=Ventricular Tachycardias: Characteristics and Management |journal=Crit Care Nurs Clin North Am |volume=28 |issue=3 |pages=317–29 |date=September 2016 |pmid=27484660 |doi=10.1016/j.cnc.2016.04.004 |url=}}</ref>
| |
|
| |
| ===Life-threatening Causes===
| |
| *Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated. They are mainly due to acute conditions that promote rapid dysfunction of automaticity and include. but are not limited to;<ref name="AjijolaTung2014">{{cite journal|last1=Ajijola|first1=Olujimi A.|last2=Tung|first2=Roderick|last3=Shivkumar|first3=Kalyanam|title=Ventricular tachycardia in ischemic heart disease substrates|journal=Indian Heart Journal|volume=66|year=2014|pages=S24–S34|issn=00194832|doi=10.1016/j.ihj.2013.12.039}}</ref><ref name="Meja LopezMalhotra2019">{{cite journal|last1=Meja Lopez|first1=Eliany|last2=Malhotra|first2=Rohit|title=Ventricular Tachycardia in Structural Heart Disease|journal=Journal of Innovations in Cardiac Rhythm Management|volume=10|issue=8|year=2019|pages=3762–3773|issn=21563977|doi=10.19102/icrm.2019.100801}}</ref><ref name="CoughtrieBehr2017">{{cite journal|last1=Coughtrie|first1=Abigail L|last2=Behr|first2=Elijah R|last3=Layton|first3=Deborah|last4=Marshall|first4=Vanessa|last5=Camm|first5=A John|last6=Shakir|first6=Saad A W|title=Drugs and life-threatening ventricular arrhythmia risk: results from the DARE study cohort|journal=BMJ Open|volume=7|issue=10|year=2017|pages=e016627|issn=2044-6055|doi=10.1136/bmjopen-2017-016627}}</ref><ref name="El-Sherif2001">{{cite journal|last1=El-Sherif|first1=Nabil|title=Mechanism of Ventricular Arrhythmias in the Long QT Syndrome: On Hermeneutics|journal=Journal of Cardiovascular Electrophysiology|volume=12|issue=8|year=2001|pages=973–976|issn=1045-3873|doi=10.1046/j.1540-8167.2001.00973.x}}</ref><ref name="urlVentricular tachycardia causes - wikidoc">{{cite web |url=https://www.wikidoc.org/index.php/Ventricular_tachycardia_causes |title=Ventricular tachycardia causes - wikidoc |format= |work= |accessdate=}}</ref>
| |
|
| |
| *[[Acute coronary syndrome]]
| |
| *[[Congestive heart failure]]
| |
| *[[NSTEMI]]
| |
| *[[STEMI]]
| |
| *[[Unstable angina]]
| |
|
| |
| ===Common Causes===
| |
| *[[Acid-base disturbances]]
| |
| *[[Antiarrhythmics]]
| |
| *[[Azithromycin]]
| |
| *[[Cardioversion]]
| |
| *[[Clarithromycin]]
| |
| *[[Claritin]]
| |
| *[[Cocaine]]
| |
| *[[Congestive heart failure]]
| |
| *[[Dilated cardiomyopathy]]
| |
| *[[Erythromycin]]
| |
| *[[Hypokalemia]]
| |
| *[[Hypomagnesemia]]
| |
| *[[Myocarditis]]
| |
| *[[Obstructive sleep apnea]]
| |
| *[[Pulmonary artery catheter]]
| |
| *[[STEMI]]
| |
| *[[Tricyclic antidepressants]]
| |
|
| |
| ==[[Pulseless ventricular tachycardia differential diagnosis|Differentiating Pulseless ventricular tachycardia from other Diseases]]== | | ==[[Pulseless ventricular tachycardia differential diagnosis|Differentiating Pulseless ventricular tachycardia from other Diseases]]== |
| Pulseless ventricular tachycardia must be differentiated from other diseases that cause wide complex tachycardia, such as [[supraventricular tachycardia with aberrant conduction]], SVT with pre-excitation and antidromic atrioventricular reentrant tachycardia.<ref name="pmid30267690">{{cite journal |vauthors= |title=Correction |journal=Heart Rhythm |volume=15 |issue=11 |pages=e282 |date=November 2018 |pmid=30267690 |doi=10.1016/j.hrthm.2018.09.024 |url=}}</ref>
| | <br /> |
|
| |
|
| ==[[Pulseless ventricular tachycardia epidemiology and demographics|Epidemiology and Demographics]]== | | ==[[Pulseless ventricular tachycardia epidemiology and demographics|Epidemiology and Demographics]]== |
|
| |
| *Ventricular tachycardia and ventricular fibrillation<ref name="pmid29173411">{{cite journal |vauthors=Tang PT, Shenasa M, Boyle NG |title=Ventricular Arrhythmias and Sudden Cardiac Death |journal=Card Electrophysiol Clin |volume=9 |issue=4 |pages=693–708 |date=December 2017 |pmid=29173411 |doi=10.1016/j.ccep.2017.08.004 |url=}}</ref> are the causes of most sudden cardiac deaths and account for about 300,000 deaths per year in the united states alone. This figure is most likely underestimated as it doesn't account for deaths due to unwitnessed dysrhythmias.<ref name="pmid21796098">{{cite journal |vauthors=McNally B, Robb R, Mehta M, Vellano K, Valderrama AL, Yoon PW, Sasson C, Crouch A, Perez AB, Merritt R, Kellermann A |title=Out-of-hospital cardiac arrest surveillance --- Cardiac Arrest Registry to Enhance Survival (CARES), United States, October 1, 2005--December 31, 2010 |journal=MMWR Surveill Summ |volume=60 |issue=8 |pages=1–19 |date=July 2011 |pmid=21796098 |doi= |url=}}</ref>
| |
| *The majority of deaths due to ventricular arrhythmias occur In adults over 35 years of age.<ref name="pmid32119354">{{cite journal |vauthors=Foglesong A, Mathew D |title= |journal= |volume= |issue= |pages= |date= |pmid=32119354 |doi= |url=}}</ref>
| |
|
| |
|
|
| |
|
| ==[[Pulseless ventricular tachycardia screening|Screening]]== | | ==[[Pulseless ventricular tachycardia screening|Screening]]== |
|
| |
|
| According to the 2017 American Heart Association guidelines screening of first-degree relatives is recommended when a patient presents with any of the symptoms such as [[Long QT syndrome|QT syndrome]], [[Hypertrophic cardiomyopathy|hypertrophic]] or [[dilated cardiomyopathy]] and right ventricular dysplasia.<ref name="pmid5731530">{{cite journal |vauthors=Shoubkhova TS |title=[Determination of the particle size of suspensions of dried bacteria by the method of turbidimetric analysis] |language=Russian |journal=Zh. Mikrobiol. Epidemiol. Immunobiol. |volume=45 |issue=7 |pages=108–10 |date=July 1968 |pmid=5731530 |doi= |url=}}</ref><ref name="pmid30554599">{{cite journal |vauthors=Flannery MD, La Gerche A |title=Sudden Death and Ventricular Arrhythmias in Athletes: Screening, De-Training and the Role of Catheter Ablation |journal=Heart Lung Circ |volume=28 |issue=1 |pages=155–163 |date=January 2019 |pmid=30554599 |doi=10.1016/j.hlc.2018.10.004 |url=}}</ref>
| | <br /> |
|
| |
|
| ==[[Pulseless ventricular tachycardia natural history, complications and prognosis|Natural History, Complications, and Prognosis]]== | | ==[[Pulseless ventricular tachycardia natural history, complications and prognosis|Natural History, Complications, and Prognosis]]== |
|
| |
|
| ==Diagnosis== | | ==Diagnosis== |
| ===Symptoms===
| |
| *On initial presentation, patients with impending [[pulseless ventricular tachycardia]] may present with signs of inadequate [[cardiac perfusion]] such as [[chest pain]], [[shortness of breath]], [[diaphoresis]], [[palpitations]], and [[syncope]].
| |
| *Physical examination may be positive for [[hypotension]], [[tachycardia]], [[tachypnea]], [[increased JVD]], and an [[S1]].
| |
| *Eventually, Pulseless ventricular tachycardia ensues and patients become unconscious and unresponsive with no detectable pulse.<ref name="pmid32119354">{{cite journal |vauthors=Foglesong A, Mathew D |title= |journal= |volume= |issue= |pages= |date= |pmid=32119354 |doi= |url=}}</ref>
| |
|
| |
| ===Electrocardiogram<ref name="pmid32119354">{{cite journal |vauthors=Foglesong A, Mathew D |title= |journal= |volume= |issue= |pages= |date= |pmid=32119354 |doi= |url=}}</ref>===
| |
| The diagnosis of Pulseless ventricular tachycardia almost completely depends on findings seen on ECG. These findings include;
| |
| *Regular R-R intervals
| |
| *Absence of p-waves largely due to rapid ventricular rates.
| |
| *A wide QRS complex and AV dissociation.
| |
|
| |
| ==Treatment == | | ==Treatment == |
|
| |
|
| Line 108: |
Line 62: |
| {{WH}} | | {{WH}} |
| {{WS}} | | {{WS}} |
| | <references /> |
