How is third-degree atrioventricular (AV) block treated?

Updated: Jul 05, 2018
  • Author: Akanksha Agrawal, MBBS; Chief Editor: Jeffrey N Rottman, MD  more...
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New-onset third-degree atrioventricular (AV) block (complete heart block) is a medical emergency. Treatment of third-degree AV block is based on the level of the block. A common misconception of an inexperienced clinician is to gauge a patient’s stability according to the heart rate and blood pressure rather than according to the symptoms and level of the block.

An asymptomatic patient with inferior wall myocardial infarction (MI) causing complete heart block at the AV node (AVN) level and a heart rate of 35 beats/min is at very little immediate risk. A patient in the acute phase of an anterior wall MI with intermittent distal high-grade block is at immediate danger of impending asystole and requires immediate preparation for pacing of some kind, even though the heart rate between asystolic episodes may be 90 beats/min.

The first, and sometimes most important, medical treatment for heart block is the withdrawal of any potentially aggravating or causative medications. Many antihypertensive, antianginal, antiarrhythmic, and heart failure medications cause AV block that resolves after withdrawal of the offending agent.

Review patient medication lists upon presentation to help rule out medication-induced or medication-aggravated heart block. Common drugs that induce AV block include beta-blockers, calcium channel blockers, antiarrhythmics, and digoxin. Withdrawal of the offending drugs is the first treatment for heart block.

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