Objectives The goal of this study was to determine how often atrioventr icular (AV) block is really caused by medications. Background Beta-blockers, verapamil , and diltiazem are considered a cause of AV block for whi...Objectives The goal of this study was to determine how often atrioventr icular (AV) block is really caused by medications. Background Beta-blockers, verapamil , and diltiazem are considered a cause of AV block for which pacemaker implantat ion is not indicated. However, it is not known if such patients can expect a ben ign course after discontinuation of the culprit medication. Methods Consecutive patients with II or III degree AV block not related to acute myocardial infarcti on, digitalis toxicity, or vasovagal syncope were studied. The level of AV block (AV-nodal or infranodal) was defined by electrocardiographic criteria. The caus e and effect relation between AV block and drugs was defined according to the re sponse to drug discontinuation. Results Of 169 patients with AV block, 92(54%) were receiving beta-blockers and/or verapamil or diltiazem. Patients receiving medications had similar clinical and electrocardiographic characteristics with p atients who had AV block in the absence of drugs. Drug discontinuation was follo wed by resolution of AV block in 41%of cases, whereas spontaneous improvement o f AV conduction occurred in 23%of patients who had AV block in the absence of d rugs. However, 56%of the patients for whom drug discontinuation led to resoluti on of AV block had recurrence of AV block in the absence of therapy. Atrioventri cular block that was “truly caused by drugs”was found in only 15%of patients who had II or III d egree AV block during therapy with beta-blockers, verapamil, or diltiazem. Conc lusions Atrioventricular block is commonly “related to drugs”but is rarely “c aused by drugs.”展开更多
文摘Objectives The goal of this study was to determine how often atrioventr icular (AV) block is really caused by medications. Background Beta-blockers, verapamil , and diltiazem are considered a cause of AV block for which pacemaker implantat ion is not indicated. However, it is not known if such patients can expect a ben ign course after discontinuation of the culprit medication. Methods Consecutive patients with II or III degree AV block not related to acute myocardial infarcti on, digitalis toxicity, or vasovagal syncope were studied. The level of AV block (AV-nodal or infranodal) was defined by electrocardiographic criteria. The caus e and effect relation between AV block and drugs was defined according to the re sponse to drug discontinuation. Results Of 169 patients with AV block, 92(54%) were receiving beta-blockers and/or verapamil or diltiazem. Patients receiving medications had similar clinical and electrocardiographic characteristics with p atients who had AV block in the absence of drugs. Drug discontinuation was follo wed by resolution of AV block in 41%of cases, whereas spontaneous improvement o f AV conduction occurred in 23%of patients who had AV block in the absence of d rugs. However, 56%of the patients for whom drug discontinuation led to resoluti on of AV block had recurrence of AV block in the absence of therapy. Atrioventri cular block that was “truly caused by drugs”was found in only 15%of patients who had II or III d egree AV block during therapy with beta-blockers, verapamil, or diltiazem. Conc lusions Atrioventricular block is commonly “related to drugs”but is rarely “c aused by drugs.”
