First degree AV block natural history, complications and prognosis: Difference between revisions
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==Complications== | ==Complications== | ||
Complications of first degree heart block include the following: | |||
* Progression to higher grade [[heart block]] | * Progression to higher grade [[heart block]] | ||
* Reduced cardiac output in [[left ventricular dysfunction]] causing [[syncope]] and [[exercise intolerance]] | * Reduced cardiac output in [[left ventricular dysfunction]] causing [[syncope]] and [[exercise intolerance]] | ||
Revision as of 13:25, 27 November 2019
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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]
Natural History
Isolated first degree heart block has few if any clinical consequences. There are no symptoms or signs associated with it, and there is little danger of progression to complete heart block.
Complications
Complications of first degree heart block include the following:
- Progression to higher grade heart block
- Reduced cardiac output in left ventricular dysfunction causing syncope and exercise intolerance
- Pacemaker syndrome
Individuals who have first degree block as part of a triad of first degree heart block, right bundle branch block, and either left anterior fascicular block or left posterior fascicular block (known as trifascicular block) may be at an increased risk of progression to complete heart block.
Prognosis
Isolated first-degree heart block has no direct clinical consequences. There are no symptoms or signs associated with it. It was originally thought of as having a benign prognosis. In the Framingham Heart Study, however, the presence of a prolonged PR interval or first degree AV block doubled the risk of developing atrial fibrillation (irregular heart beat), tripled the risk of requiring an artificial pacemaker, and was associated with a small increase in mortality. This risk was proportional to the degree of PR prolongation.[1]
A subset of individuals with the triad of first-degree heart block, right bundle branch block, and either left anterior fascicular block or left posterior fascicular block (known as trifascicular block) may be at an increased risk of progression to complete heart block. First degree block in the setting of acute myocardial infarction can increase the risk of acquiring higher degree blocks. Similarly markedly prolonged PR interval in the setting of left ventricular dysfunction can lead to reduced cardiac output.
In a prospective study of over 938 patients it was found that patients with first degree AV block had an increased risk of hospitalization for heart failure, cardiovascular mortality and all cause mortality.
Presence of first degree AV block in healthy people and in patients with coronary heart disease is shown to be associated with higher risk of morbidity and mortality.
References
- ↑ Cheng S, Keyes MJ, Larson MG, McCabe EL, Newton-Cheh C, Levy D, Benjamin EJ, Vasan RS, Wang TJ (2009). "Long-term outcomes in individuals with prolonged PR interval or first-degree atrioventricular block". JAMA. 301 (24): 25712577. doi:10.1001/jama.2009.888.