Effects of antiarrhythmic drugs on inappropriate shocks in patients with implantable cardioverter defibrillators.
BACKGROUND
Patients with atrial fibrillation (AF) or congestive heart failure (CHF) are more vulnerable to inappropriate shocks from implantable cardioverter-defibrillators (ICDs), but the effect of antiarrhythmic drugs in these patients remains unknown.


RESULTS
A total of 55 patients with AF and/or CHF (New York Heart Association functional class > or =III) who had ICDs were divided into 3 groups [amiodarone (n=24), sotalol (n=12), beta-blocker (n=19)] and the cumulative rates of inappropriate shocks were compared. The baseline characteristics of the 3 groups were not significantly different. The 4-year event rate of inappropriate shocks was 27.3% in the amiodarone group, 54.3% in the sotalol group, and 70.6% in the beta-blocker group (amiodarone vs beta-blocker: log-rank p=0.003; sotalol vs beta-blocker: log-rank p=0.16; amiodarone vs sotalol: log-rank p=0.29). Amiodarone reduced the risk of inappropriate shocks significantly as compared with beta-blockers (hazard ratio (HR) 0.17; 95% confidence interval (CI) 0.05-0.64; p=0.008), whereas sotalol did not (HR 0.57; 95%CI 0.19-1.68; p=0.3). Amiodarone was discontinued in 4 patients (16.7%) because of pulmonary toxicity and the dose was reduced in 4 patients (16.7%) because of a thyroid function abnormality.


CONCLUSIONS
Amiodarone is more effective than sotalol or beta-blockers in preventing inappropriate ICD shocks in patients with AF or CHF, but it has a significant risk of drug-related adverse effects.
Lee
Chang Hoon
CH
Department of Internal Medicine, University of Ulsan College of Medicine, Seoul, Republic of Korea.
Nam
Gi-Byoung
GB
Park
Hyun-Gu
HG
Kim
Hyung Yong
HY
Park
Kyoung-Min
KM
Kim
Jun
J
Choi
Kee-Joon
KJ
Kim
You-Ho
YH
D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000494:pharmacology / Q000633:toxicity; D000368:Aged; D000638:Amiodarone / Q000008:administration & dosage / Q000494:pharmacology / Q000633:toxicity; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage* / Q000494:pharmacology / Q000633:toxicity; D001281:Atrial Fibrillation / Q000628:therapy; D017147:Defibrillators, Implantable / Q000009:adverse effects*; D004556:Electric Injuries / Q000188:drug therapy / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D006333:Heart Failure / Q000628:therapy; D006801:Humans; D008171:Lung Diseases / Q000139:chemically induced; D008297:Male; D008875:Middle Aged; D012769:Shock / Q000517:prevention & control; D013015:Sotalol / Q000008:administration & dosage / Q000494:pharmacology / Q000633:toxicity
D000319:Adrenergic beta-Antagonists; D000889:Anti-Arrhythmia Agents; D013015:Sotalol; D000638:Amiodarone