Second degree AV block causes: Difference between revisions
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==Overview== | ==Overview== | ||
Atrioventricular (AV) block is defined as an interruption in the transmission of an impulse, either transient or permanent, from the atria to the ventricles due to an anatomic or functional impairment in the conduction system. In second degree AV block, some atrial impulses fail to reach the ventricles. Wenckebach described progressive delay between atrial and ventricular contraction and the eventual failure of an atrial beat to reach the ventricles. Mobitz subsequently divided second degree AV block into two subtypes, as determined by the findings on the [[electrocardiogram]]. In Mobitz type I AV block, progressive PR interval prolongation precedes a non-conducted P wave. While in Mobitz type II AV block, the PR interval remains unchanged prior to a P wave that suddenly fails to conduct to the ventricles. | Atrioventricular (AV) block is defined as an interruption in the transmission of an impulse, either transient or permanent, from the atria to the ventricles due to an anatomic or functional impairment in the conduction system. In second degree AV block, some atrial impulses fail to reach the ventricles. Wenckebach described progressive delay between atrial and ventricular contraction and the eventual failure of an atrial beat to reach the ventricles. Mobitz subsequently divided second degree AV block into two subtypes, as determined by the findings on the [[electrocardiogram]]. In Mobitz type I AV block, progressive PR interval prolongation precedes a non-conducted P wave. While in Mobitz type II AV block, the PR interval remains unchanged prior to a P wave that suddenly fails to conduct to the ventricles. | ||
==Causes== | ==Causes== | ||
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===Common Causes=== | ===Common Causes=== | ||
* [[Acute rheumatic fever]] | * [[Acute rheumatic fever]] | ||
* [[Bacterial endocarditis | * [[Bacterial endocarditis]] | ||
* [[aortic stenosis|Calcific aortic stenosis]] | * [[aortic stenosis|Calcific aortic stenosis]] | ||
* [[Degenerative disease]] | * [[Degenerative disease]] | ||
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* [[Hypertension]] | * [[Hypertension]] | ||
* [[Iatrogenic]] after surgical correction of [[VSD]], [[tetralogy of Fallot]], and [[endocardial cushion defect]] | * [[Iatrogenic]] after surgical correction of [[VSD]], [[tetralogy of Fallot]], and [[endocardial cushion defect]] | ||
* | * [[ST elevation MI|Inferior ST elevation MI]] | ||
* [[mitral valve sclerosis|Massive calcification of the mitral annulus]] | * [[mitral valve sclerosis|Massive calcification of the mitral annulus]] | ||
* [[ | * [[Myocarditis]] | ||
* [[PR interval|Normal variants]] | * [[PR interval|Normal variants]] | ||
* [[chest trauma|Penetrating and non-penetrating trauma of the chest]] | * [[chest trauma|Penetrating and non-penetrating trauma of the chest]] | ||
* [[Lev's disease|Sclerodegenerative disease of the electrical conduction system]] | * [[Lev's disease|Sclerodegenerative disease of the electrical conduction system]] | ||
* [[Verapamil]] | * [[Verapamil]] | ||
* [[Beta blocker|β blockers]] | |||
===Causes by Organ System=== | ===Causes by Organ System=== | ||
Revision as of 17:50, 6 September 2013
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Cafer Zorkun, M.D., Ph.D. [2] Mahmoud Sakr, M.D. [3]
Overview
Atrioventricular (AV) block is defined as an interruption in the transmission of an impulse, either transient or permanent, from the atria to the ventricles due to an anatomic or functional impairment in the conduction system. In second degree AV block, some atrial impulses fail to reach the ventricles. Wenckebach described progressive delay between atrial and ventricular contraction and the eventual failure of an atrial beat to reach the ventricles. Mobitz subsequently divided second degree AV block into two subtypes, as determined by the findings on the electrocardiogram. In Mobitz type I AV block, progressive PR interval prolongation precedes a non-conducted P wave. While in Mobitz type II AV block, the PR interval remains unchanged prior to a P wave that suddenly fails to conduct to the ventricles.
Causes
Life Threatening Causes
Life-threatening conditions can result in death or permanent disability within 24 hours if left untreated.
- Acute myocardial infarction
- Acute rheumatic fever
- Bacterial endocarditis
- Myocarditis
- Severe hypothermia
Common Causes
- Acute rheumatic fever
- Bacterial endocarditis
- Calcific aortic stenosis
- Degenerative disease
- Digoxin
- Dilated cardiomyopathy
- Diltiazem
- Enhanced vagal tone
- HCM
- Hypertension
- Iatrogenic after surgical correction of VSD, tetralogy of Fallot, and endocardial cushion defect
- Inferior ST elevation MI
- Massive calcification of the mitral annulus
- Myocarditis
- Normal variants
- Penetrating and non-penetrating trauma of the chest
- Sclerodegenerative disease of the electrical conduction system
- Verapamil
- β blockers