Paroxysmal atrioventricular block: clinical experience with 20 patients

Background: Paroxysmal atrioventricular (AV) block is an ill-defined entity, previously described in sporadic cases in association with vasovagal reaction, coronary angiography and distal conduction disease. Methods: We describe 20 patients (10 women) aged 26 to 80 years with symptomatic paroxysmal AV block. Results: Eight patients had ischemic heart disease—three with dilated cardiomyopathy, and two with co-existing carotid sinus hypersensitivity. Eight were taking chronic AV blockers. In five patients, the paroxysmal AV block occurred during a vagal reaction, in one during migranotic headaches, in one following aortic valve replacement and in one while recovering from acute myocardial infarction. The events lasted between 2.2 and 36 s. In 10 patients, the QRS configuration on the electrocardiogram was wide. Immediate treatment consisted of intravenous atropine and fluid supplements in two patients, discontinuation of the AV blocking agents in four, and the insertion of a temporary pacemaker in eight. Seventeen patients required a permanent pacemaker. Conclusions: Paroxysmal AV block is an underestimated clinical entity related to vagal reaction, AV blocking drugs and distal conduction disease. Most of our patients eventually required implantation of a permanent pacemaker.