Paroxysmal AV block overview: Difference between revisions
Jump to navigation
Jump to search
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
*Atrioventricular block may be classified anatomically by the site of block, usually divided into atrioventricular nodal, intra-Hisian (within the His bundle itself), and infra-Hisian (below the His bundle). | *[[Atrioventricular block]] may be classified [[anatomically]] by the site of block, usually divided into [[atrioventricular nodal]], [[intra-Hisian]] (within the His bundle itself), and [[infra-Hisian]] (below the His bundle). | ||
*Paroxysmal AV block is defined as a delayed escape rhythm which repetitively blocks conduction from the atria to the ventricles, thereby causing [[syncope]], conduction defects such as [[asystole]] and [[sudden cardiac death]]. | *[[Paroxysmal AV block]] is defined as a delayed [[escape rhythm]] which repetitively blocks [[conduction]] from the [[atria]] to the [[ventricles]], thereby causing [[syncope]], [[conduction]] defects such as [[asystole]] and [[sudden cardiac death]]. | ||
*It may or may not be associated with [[Phase 3]] or [[Phase 4]] [[conduction]] defects. | *It may or may not be associated with [[Phase 3]] or [[Phase 4]] [[conduction]] defects. | ||
*It may be due to an increased [[vagal]] tone, innately low [[adenosine]] levels or an intrinsic conduction defect, all of which lead to different [[ECG]] presentations. | *It may be due to an increased [[vagal]] tone, innately low [[adenosine]] levels or an intrinsic conduction defect, all of which lead to different [[ECG]] presentations. | ||
| Line 7: | Line 7: | ||
*The site of [[block]] may be [[clinically]] important and can be determined by invasive [[EPS]] when not apparent from the [[ECG]] and [[clinical]] circumstances. | *The site of [[block]] may be [[clinically]] important and can be determined by invasive [[EPS]] when not apparent from the [[ECG]] and [[clinical]] circumstances. | ||
*In general, [[atrioventricular block]] at the [[atrioventricular nodal]] level is associated with slower progression, a faster and more reliable atrioventricular [[junctional escape mechanism]], and greater responsiveness to [[autonomic]] manipulation such as [[atropine]], [[isoproterenol]], and [[epinephrine]] administration. | *In general, [[atrioventricular block]] at the [[atrioventricular nodal]] level is associated with slower progression, a faster and more reliable atrioventricular [[junctional escape mechanism]], and greater responsiveness to [[autonomic]] manipulation such as [[atropine]], [[isoproterenol]], and [[epinephrine]] administration. | ||
**In contrast, [[atrioventricular block]] within or below the [[His bundle]] may progress rapidly and unexpectedly, is associated with a slower and more unpredictable [[ventricular escape mechanism]], will not respond to [[atropine]] but will sometimes improve with [[catecholamines]]. | **In contrast, [[atrioventricular block]] within or below the [[His bundle]] may progress rapidly and unexpectedly, is associated with a slower and more unpredictable [[ventricular escape mechanism]], will not respond to [[atropine]] but will sometimes improve with [[catecholamines]]. | ||
<references /> | <references /> | ||
Revision as of 08:24, 26 June 2020
- Atrioventricular block may be classified anatomically by the site of block, usually divided into atrioventricular nodal, intra-Hisian (within the His bundle itself), and infra-Hisian (below the His bundle).
- Paroxysmal AV block is defined as a delayed escape rhythm which repetitively blocks conduction from the atria to the ventricles, thereby causing syncope, conduction defects such as asystole and sudden cardiac death.
- It may or may not be associated with Phase 3 or Phase 4 conduction defects.
- It may be due to an increased vagal tone, innately low adenosine levels or an intrinsic conduction defect, all of which lead to different ECG presentations.
- Insufficient data is available regarding the exact etiology, diagnostic study of choice and treatment of paroxysmal AV blocks.
- It can be thought of more as a disease of exclusion. However,efforts must be made to have a standardized approach to such patients.
- The site of block may be clinically important and can be determined by invasive EPS when not apparent from the ECG and clinical circumstances.
- In general, atrioventricular block at the atrioventricular nodal level is associated with slower progression, a faster and more reliable atrioventricular junctional escape mechanism, and greater responsiveness to autonomic manipulation such as atropine, isoproterenol, and epinephrine administration.
- In contrast, atrioventricular block within or below the His bundle may progress rapidly and unexpectedly, is associated with a slower and more unpredictable ventricular escape mechanism, will not respond to atropine but will sometimes improve with catecholamines.