Effects of amiodarone on cardiac electrophysiology in right ventricular rapid pacing-induced heart failure dogs

ＥｆｅｃｔｓｏｆａｍｉｏｄａｒｏｎｅｏｎｃａｒｄｉａｃｅｌｅｃｔｒｏｐｈｙｓｉｏｌｏｇｙｉｎｒｉｇｈｔｖｅｎｔｒｉｃｕｌａｒｒａｐｉｄｐａｃｉｎｇｉｎｄｕｃｅｄｈｅａｒｔｆａｉｌｕｒｅｄｏｇｓＺＨＯＵＳｈｕＸｉａｎ１，ＺＨＡＮＧＸｕＭｉｎｇ，Ｗ...

AIM: To study the effects of amiodarone (Ami) on cardiac electrophysiologic properties and ventricular fibrillation threshold (VFT) in right ventricular rapid pacing induced congestive heart failure (CHF) dogs. METHODS: Dogs ( n =25) were randomly allocated into 3 groups: A) control group; B) CHF group induced by right ventricular rapid pacing (4 pulses·s -1 ) for 4-5 wk; C) CHF models po Ami 300 mg·d -1 for 4-5 wk. The electrophysiologic parameters and VFT were evaluated by electric stimulation and monophasic action potential (MAP) recording. RESULTS: In CHF models, ventricular MAP duration (MAPD 90 ), ventricular late repolarization duration (VLRD), and intra ventricular conduction time (IVCT) were prolonged by 43 % , 318 % , and 19 % , respectively; the ratio of ventricular effective refractory period (VERP) to MAPD 90 (VERP/MAPD 90 ) and VFT were decreased by 13 % and 48 % respectively; the dispersion of ventricular recovery time (RT D) was increased by 185 %. In CHF models, Ami had no effects on ventricular MAPD 90 , but increased VERP/MAPD 90 , IVCT, and VFT by 15 %, 10 %, and 67 %, respectively, shortened VLRD by 87 % ; and decreased RT D by 87 %. Ami had no significant influences on the hemodynamic parameters of the CHF dogs. CONCLUSION: Ami normalizes the cardiac electrophysiologic properties in CHF dogs.