Isorhythmic A-V dissociation: Difference between revisions
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{{SI}} | |||
{{CMG}}; {{AE}} {{VR}} | |||
{{SK}} Isorhythmic AV dissociation | |||
==Overview== | |||
An [[atrioventricular dissociation]] characterized by independent and equally beating atrial and ventricular pacemakers, in the absence of a retrograde conduction from the ventricular depolarization to the atria is called as isorhythmic AV dissociation. Isorhythmic dissociation is not common in the general population and it is the most innocent type of AV dissociation. | |||
==Pathophysiology== | |||
Isorhythmic AV dissociation is a [[AV dissociation]] initiated by slowing of [[SA node]] due to sinus arrhythmia, [[sinus bradycardia]], [[sinus arrest]], or [[sinoatrial block]]. This allows an independent ventricular pacemaker response like either [[junctional rhythm]] (giving a normal or near normal QRS appearance and duration) or [[idioventricular rhythm]] (with a more bizarre, wide QRS) to take over the ventricles. In the presence of some degree of antegrade and retrograde [[atrioventricular block]], there is a synchronization of independently beating sinus or atrial pacemaker with the junctional or ventricular pacemaker such that each discharges in the absolute refractory period of the other. | |||
*Both the independent atrial and ventricular rates are [[Bradycardia|bradycardic]] and nearly identical, in contrast to other types of AV dissociation. When they both are bradycardic and synchronized, captures will not occur and a complete AV dissociation will ensue. | |||
*Both [[fusion beats]] and [[capture beats]] may be present when either the atrial or ventricular rate becomes faster than the other with antegrade or retrograde conduction. | |||
*Both [[P waves]] and the QRS complexes look related with the P wave moving closer to and then farther away from the QRS, maintaining an illusion of a normal atrioventricular conduction sequence. Occasionally, the P wave might move into and get buried within the QRS complex, only to move back out again in front of the QRS in the subsequent beats. The two pacemakers will remain independent as long as the SA node rate is bradycardic. | |||
:*When this rhythm occurs intermittently with normal sinus rhythm, it is called accrochage. | |||
:*When the isorhythmic dissociation is persistent, it is called as synchronization. Synchronization has two distinct patterns like, the pattern which is characterized by a rhythmic fluctuation of the interval between the P and QRS waves, most often the P wave oscillating gradually back and forth across the QRS; that is, with periodically varying of [[PR interval|P-R]] and R-P intervals. In the second pattern, the P-R or R-P interval do not undergo rhythmic fluctuations, but the P and [[R waves]] are in a relatively fixed position with respect to each other.<ref name="pmid11993309">{{cite journal | author = Levy MN, Edflstein J | title = The mechanism of synchronization in isorhythmic A-V dissociation. II. Clinical studies | journal = [[Circulation]] | volume = 42 | issue = 4 | pages = 689–99 | year = 1970 | month = October | pmid = 11993309 | doi = | url = http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=11993309 | issn = }}</ref> | |||
==Causes== | |||
===Life Threatening Causes=== | |||
Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated. | |||
*[[Diabetic ketoacidosis]] | |||
*[[Digitalis toxicity]] | |||
*[[Myocardial infarction]] | |||
*[[Myocardial rupture]] | |||
*[[Organophosphate poisoning]] | |||
===Common Causes=== | |||
*[[Acetylcholine]] | |||
*[[Acute coronary syndrome]] | |||
*[[Acute rheumatic fever]] | |||
*[[Amiodarone]] | |||
*[[Antiarrhythmic agents]] | |||
*[[Beta-blockers]] | |||
*[[Calcium channel blockers]] | |||
*[[Cardiomyopathy]] | |||
*[[Congestive heart failure]] | |||
*[[Digitalis toxicity]] | |||
*[[Hypertensive heart disease]] | |||
*[[Ischemic heart disease]] | |||
*[[Myocarditis]] | |||
*[[Sick sinus syndrome]] | |||
*[[Sinus arrest]] | |||
*[[Sinus bradycardia]] | |||
===Causes by Organ System=== | |||
{|style="width:80%; height:100px" border="1" | |||
|style="height:100px"; style="width:25%" border="1" bgcolor="LightSteelBlue" | '''Cardiovascular''' | |||
|style="height:100px"; style="width:75%" border="1" bgcolor="Beige" | [[Acute coronary syndrome]], [[acute rheumatic fever]], [[amyloidosis]], [[Andersen cardiodysrhythmic periodic paralysis]], [[Brugada syndrome]], [[cardiac tumor#heart in lymphomas|cardiac lymphoma]], [[cardiac transplantation]], [[Carotid sinus hypersensitivity|cardioinhibitory syncope]], [[complete heart block]], [[congenital heart disease]], [[congestive heart failure]], [[reperfusion injury|coronary reperfusion therapy]], [[dilated cardiomyopathy]], [[hypertensive heart disease]], [[hypertrophic cardiomyopathy]], [[ischemic heart disease]], [[Jervell and Lange-Nielsen syndrome]], [[Lev's disease]], [[long QT syndrome]], [[myocardial bridging]], [[myocardial contusion]], [[myocardial infarction]], [[myocardial rupture]], [[myocarditis]], [[NSTEMI]], [[pericarditis]], [[Romano-Ward syndrome]], [[sick sinus syndrome]], [[sinoatrial block]], [[sinus arrest]], [[sinus bradycardia]], [[sinus node disease|sinus node fibrosis]], [[STEMI]], [[tachycardia-bradycardia syndrome]], [[Timothy syndrome]], [[valvular heart disease]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Chemical/Poisoning''' | |||
|bgcolor="Beige"| [[Berberine]], [[carbamate|carbamate poisoning]], [[grayanotoxin]], [[organophosphate|organophosphate poisoning]], [[parathion poisoning]], [[spider bite#spider venom|poisonous spider bites]], [[pyrethroid|pyrethroid poisoning]], [[Arizona bark scorpion|scorpion toxin]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Dental''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Dermatologic''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Drug Side Effect''' | |||
|bgcolor="Beige"| [[Acetylcholine]], [[all-trans retinoic acid]], [[amiodarone]], [[anthracyclines]], [[antiarrhythmic drugs]], [[barbiturate]], [[beta-blockers]], [[bupivacaine]], [[calcium channel blockers]], [[carbamazepine]], [[cholinesterase inhibitors]], [[cimetidine]], [[citalopram]], [[clonidine]], [[daunorubicin]], [[digoxin]], [[diltiazem]], [[diphenhydramine]], [[donepezil]], [[doxorubicin]], [[edrophonium]], [[epirubicin]], [[granisetron]], [[guanethidine]], [[halothane]], [[idarubicin]], [[isoprenaline]], [[lithium]], [[mepivacaine]], [[mesalamine]], [[methyldopa]], [[methylprednisolone]], [[nelfinavir]], [[neostigmine]], [[nicorandil]], [[phenothiazine]], [[phenytoin]], [[procainamide]], [[propafenone]], [[propanolol]], [[propofol]], [[pyridostigmine]], [[quinidine]], [[remifentanil]], [[reserpine]], [[ropivacaine]], [[tacrine]], [[thiamylal]], [[timolol]], [[tramadol]], [[tricyclic antidepressants]], [[urapidil]], [[verapamil]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Ear Nose Throat''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Endocrine''' | |||
|bgcolor="Beige"| [[Diabetic ketoacidosis]], [[Hashimoto's thyroiditis]], [[hyperthyroidism]], [[hypothyroidism]], [[pheochromocytoma]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Environmental''' | |||
|bgcolor="Beige"| [[Hypothermia]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Gastroenterologic''' | |||
|bgcolor="Beige"| [[Amyloidosis]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Genetic''' | |||
|bgcolor="Beige"| [[Brugada syndrome]], [[Emery-Dreifuss muscular dystrophy]], [[Jervell and Lange-Nielsen syndrome]], [[Kearns-Sayre syndrome]], [[Limb-girdle muscular dystrophy|limb-girdle muscular dystrophy type 1B (LGMD1B)]], [[long QT syndrome]], [[muscular dystrophy]], [[myotonic dystrophy]], [[Romano-Ward syndrome]], [[Timothy syndrome]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Hematologic''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Iatrogenic''' | |||
|bgcolor="Beige"| [[Cardiac catheterization]], [[cardiac resynchronization therapy]], [[cardiac transplantation]], [[coronary artery bypass grafting]], [[Fontan procedure]], [[heart surgery]], [[lung transplantation|post lung transplantation]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Infectious Disease''' | |||
|bgcolor="Beige"| [[Acute rheumatic fever]], [[Chagas disease]], [[diptheria]], [[Lyme disease]], [[septic shock]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Musculoskeletal/Orthopedic''' | |||
|bgcolor="Beige"| [[Muscular dystrophy]], [[myotonic dystrophy]], [[Timothy syndrome]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Neurologic''' | |||
|bgcolor="Beige"| [[brain damage|Severe brain injury]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Nutritional/Metabolic''' | |||
|bgcolor="Beige"| [[Diabetic ketoacidosis]], [[hyperkalemia]], [[hypermagnesemia]], [[hypocalcemia]], [[metabolic acidosis]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Obstetric/Gynecologic''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Oncologic''' | |||
|bgcolor="Beige"| [[cardiac tumor#heart in lymphomas|Cardiac lymphoma]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Ophthalmologic''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Overdose/Toxicity''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Psychiatric''' | |||
|bgcolor="Beige"| [[anorexia nervosa|Severe anorexia nervosa]], [[Takotsubo cardiomyopathy]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Pulmonary''' | |||
|bgcolor="Beige"| [[Hypoxia]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Renal/Electrolyte''' | |||
|bgcolor="Beige"| [[Acute renal failure]], [[amyloidosis]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Rheumatology/Immunology/Allergy''' | |||
|bgcolor="Beige"| [[Neonatal lupus erythematosus]], [[scleroderma]], [[Sjogren's syndrome]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Sexual''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Trauma''' | |||
|bgcolor="Beige"| [[Myocardial contusion]] | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Urologic''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Miscellaneous''' | |||
|bgcolor="Beige"| [[Idiopathic]] | |||
|- | |||
|} | |||
===Causes in Alphabetical Order=== | |||
{{col-begin|width=80%}} | |||
{{col-break|width=33%}} | |||
*[[Acetylcholine]] | |||
*[[Acute coronary syndrome]] | |||
*[[Acute renal failure]] | |||
*[[Acute rheumatic fever]] | |||
*[[All-trans retinoic acid]] | |||
*[[Amiodarone]] | |||
*[[Amyloidosis]] | |||
*[[Andersen cardiodysrhythmic periodic paralysis]] | |||
*[[Anthracyclines]] | |||
*[[Antiarrhythmic drugs]] | |||
*[[Barbiturate]] | |||
*[[Berberine]] | |||
*[[Beta-blockers]] | |||
*[[Brugada syndrome]] | |||
*[[Bupivacaine]] | |||
*[[Calcium channel blockers]] | |||
*[[carbamate|Carbamate poisoning]] | |||
*[[Carbamazepine]] | |||
*[[Cardiac catheterization]] | |||
*[[cardiac tumor#heart in lymphomas|Cardiac lymphoma]] | |||
*[[Cardiac resynchronization therapy]] | |||
*[[Cardiac transplantation]] | |||
*[[Carotid sinus hypersensitivity|Cardioinhibitory syncope]] | |||
*[[Chagas disease]] | |||
*[[Cholinesterase inhibitors]] | |||
*[[Cimetidine]] | |||
*[[Citalopram]] | |||
*[[Clonidine]] | |||
*[[Complete heart block]] | |||
*[[Congenital heart disease]] | |||
*[[Congestive heart failure]] | |||
*[[Coronary artery bypass grafting]] | |||
*[[reperfusion injury|Coronary reperfusion therapy]] | |||
*[[Daunorubicin]] | |||
*[[Diabetic ketoacidosis]] | |||
*[[Digoxin]] | |||
*[[Dilated cardiomyopathy]] | |||
*[[Diltiazem]] | |||
*[[Diphenhydramine]] | |||
*[[Diptheria]] | |||
*[[Donepezil]] | |||
*[[Doxorubicin]] | |||
*[[Edrophonium]] | |||
*[[Emery-Dreifuss muscular dystrophy]] | |||
{{col-break|width=33%}} | |||
*[[Epirubicin]] | |||
*[[Fontan procedure]] | |||
*[[Granisetron]] | |||
*[[Grayanotoxin]] | |||
*[[Guanethidine]] | |||
*[[Halothane]] | |||
*[[Hashimoto's thyroiditis]] | |||
*[[Heart surgery]] | |||
*[[Hyperkalemia]] | |||
*[[Hypermagnesemia]] | |||
*[[Hypertensive heart disease]] | |||
*[[Hyperthyroidism]] | |||
*[[Hypertrophic cardiomyopathy]] | |||
*[[Hypocalcemia]] | |||
*[[Hypothermia]] | |||
*[[Hypoxia]] | |||
*[[Idarubicin]] | |||
*[[Idiopathic]] | |||
*[[Ischemic heart disease]] | |||
*[[Isoprenaline]] | |||
*[[Jervell and Lange-Nielsen syndrome]] | |||
*[[Kearns-Sayre syndrome]] | |||
*[[Lev's disease]] | |||
*[[Limb-girdle muscular dystrophy|Limb-girdle muscular dystrophy type 1B (LGMD1B)]] | |||
*[[Lithium]] | |||
*[[Long QT syndrome]] | |||
*[[Lyme disease]] | |||
*[[Mepivacaine]] | |||
*[[Mesalamine]] | |||
*[[Metabolic acidosis]] | |||
*[[Methyldopa]] | |||
*[[Methylprednisolone]] | |||
*[[Muscular dystrophy]] | |||
*[[Myocardial bridging]] | |||
*[[Myocardial contusion]] | |||
*[[Myocardial infarction]] | |||
*[[Myocardial rupture]] | |||
*[[Myocarditis]] | |||
*[[Myotonic dystrophy]] | |||
*[[Nelfinavir]] | |||
*[[Neonatal lupus erythematosus]] | |||
*[[Neostigmine]] | |||
*[[Nicorandil]] | |||
*[[NSTEMI]] | |||
{{col-break|width=33%}} | |||
*[[organophosphate|Organophosphate poisoning]] | |||
*[[Parathion poisoning]] | |||
*[[Pericarditis]] | |||
*[[Phenothiazine]] | |||
*[[Phenytoin]] | |||
*[[Pheochromocytoma]] | |||
*[[spider bite#spider venom|Poisonous spider bites]] | |||
*[[lung transplantation|Post lung transplantation]] | |||
*[[Procainamide]] | |||
*[[Hypothyroidism]] | |||
*[[Propafenone]] | |||
*[[Propanolol]] | |||
*[[Propofol]] | |||
*[[pyrethroid|Pyrethroid poisoning]] | |||
*[[Pyridostigmine]] | |||
*[[Quinidine]] | |||
*[[Remifentanil]] | |||
*[[Reserpine]] | |||
*[[Romano-Ward syndrome]] | |||
*[[Ropivacaine]] | |||
*[[Scleroderma]] | |||
*[[Arizona bark scorpion|Scorpion toxin]] | |||
*[[Septic shock]] | |||
*[[anorexia nervosa|Severe anorexia nervosa]] | |||
*[[brain damage|Severe brain injury]] | |||
*[[Sick sinus syndrome]] | |||
*[[Sinoatrial block]] | |||
*[[Sinus arrest]] | |||
*[[Sinus bradycardia]] | |||
*[[sinus node disease|Sinus node fibrosis]] | |||
*[[Sjogren's syndrome]] | |||
*[[STEMI]] | |||
*[[Tachycardia-bradycardia syndrome]] | |||
*[[Tacrine]] | |||
*[[Takotsubo cardiomyopathy]] | |||
*[[Thiamylal]] | |||
*[[Timolol]] | |||
*[[Timothy syndrome]] | |||
*[[Tramadol]] | |||
*[[Tricyclic antidepressants]] | |||
*[[Urapidil]] | |||
*[[Valvular heart disease]] | |||
*[[Verapamil]] | |||
{{col-end}} | |||
== References == | |||
{{Reflist|2}} | |||
[[Category:Cardiology]] | [[Category:Cardiology]] | ||
[[Category:Up-To-Date]] | |||
[[Category:Up-To-Date cardiology]] | |||
[[Category:Arrhythmia]] | |||
[[Category:Electrophysiology]] | [[Category:Electrophysiology]] | ||
[[Category: | [[Category:Disease]] | ||
{{WH}} | |||
{{WS}} |
Latest revision as of 18:48, 4 September 2013
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vendhan Ramanujam M.B.B.S [2]
Synonyms and keywords: Isorhythmic AV dissociation
Overview
An atrioventricular dissociation characterized by independent and equally beating atrial and ventricular pacemakers, in the absence of a retrograde conduction from the ventricular depolarization to the atria is called as isorhythmic AV dissociation. Isorhythmic dissociation is not common in the general population and it is the most innocent type of AV dissociation.
Pathophysiology
Isorhythmic AV dissociation is a AV dissociation initiated by slowing of SA node due to sinus arrhythmia, sinus bradycardia, sinus arrest, or sinoatrial block. This allows an independent ventricular pacemaker response like either junctional rhythm (giving a normal or near normal QRS appearance and duration) or idioventricular rhythm (with a more bizarre, wide QRS) to take over the ventricles. In the presence of some degree of antegrade and retrograde atrioventricular block, there is a synchronization of independently beating sinus or atrial pacemaker with the junctional or ventricular pacemaker such that each discharges in the absolute refractory period of the other.
- Both the independent atrial and ventricular rates are bradycardic and nearly identical, in contrast to other types of AV dissociation. When they both are bradycardic and synchronized, captures will not occur and a complete AV dissociation will ensue.
- Both fusion beats and capture beats may be present when either the atrial or ventricular rate becomes faster than the other with antegrade or retrograde conduction.
- Both P waves and the QRS complexes look related with the P wave moving closer to and then farther away from the QRS, maintaining an illusion of a normal atrioventricular conduction sequence. Occasionally, the P wave might move into and get buried within the QRS complex, only to move back out again in front of the QRS in the subsequent beats. The two pacemakers will remain independent as long as the SA node rate is bradycardic.
- When this rhythm occurs intermittently with normal sinus rhythm, it is called accrochage.
- When the isorhythmic dissociation is persistent, it is called as synchronization. Synchronization has two distinct patterns like, the pattern which is characterized by a rhythmic fluctuation of the interval between the P and QRS waves, most often the P wave oscillating gradually back and forth across the QRS; that is, with periodically varying of P-R and R-P intervals. In the second pattern, the P-R or R-P interval do not undergo rhythmic fluctuations, but the P and R waves are in a relatively fixed position with respect to each other.[1]
Causes
Life Threatening Causes
Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.
- Diabetic ketoacidosis
- Digitalis toxicity
- Myocardial infarction
- Myocardial rupture
- Organophosphate poisoning
Common Causes
- Acetylcholine
- Acute coronary syndrome
- Acute rheumatic fever
- Amiodarone
- Antiarrhythmic agents
- Beta-blockers
- Calcium channel blockers
- Cardiomyopathy
- Congestive heart failure
- Digitalis toxicity
- Hypertensive heart disease
- Ischemic heart disease
- Myocarditis
- Sick sinus syndrome
- Sinus arrest
- Sinus bradycardia
Causes by Organ System
Causes in Alphabetical Order
References
- ↑ Levy MN, Edflstein J (1970). "The mechanism of synchronization in isorhythmic A-V dissociation. II. Clinical studies". Circulation. 42 (4): 689–99. PMID 11993309. Unknown parameter
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ignored (help)