Abstract 10164: Dronedarone but Not Amiodarone Ameliorates Atrial Tachyarrhythmia-Induced Decrease of Ventricular Microperfusion
Introduction: Atrial fibrillation (AF) is associated with an increased risk for acute coronary syndromes. AF-induced myocardial ischemia seems to be related to disturbance of ventricular microcirculation. This study was conducted to evaluate the effects of dronedarone (DRO) and amiodarone (AMIO) infusion on ventricular macro- and microperfusion during rapid atrial pacing (RAP).
Methods: Coronary flow reserve (CFR, microvascular perfusion marker) and fractional flow reserve (FFR, epicardial coronary artery flow marker) were determined in the left anterior descending artery in a total of 30 pigs using a sensortipped thermodilution and pressure guidewire. Measurements were conducted at baseline, and after 6h of RAP with 600 bpm and/or DRO/AMIO infusion. RAP alone was performed in 6 pigs. Another 6 animals underwent RAP in the presence of DRO i.v. (10mg/kg) and 5 with AMIO i.v. (5mg/kg). In addition, 6 pigs were instrumented without intervention (Sham); 7 animals received DRO alone.
Results: FFR measurement (baseline=100%) revealed a decreased flow reserve only in RAP and AMIO animals after 6h compared to all other groups (RAP:93±6%; RAP+AMIO:82±20%; p<0.05). FFR, however, did not drop below <0.8 in any animal. DRO infusion increased FFR compared to RAP after 6h (DRO:105±5% vs RAP:93±6%; p<0.05). RAP and AMIO significantly decreased CFR (baseline=100%) when compared with any other group (RAP:57±11% and RAP+AMIO:54±18% vs Sham:103±14% vs RAP+DRO:96±13% vs DRO:110±17%; p<0.05). DRO infusion abolished RAP induced decrease in CFR with a tendency towards an increased CFR compared to baseline (+10%). DRO infusion did not alter QTc compared to Sham, but QTc increased in the DRO group during infusion (baseline Qtc 372±10ms vs 6h DRO 408±36ms). There were no significant differences in cardiac/systemic hemodynamic parameters between all groups.
Conclusions: RAP impaires left ventricular microcirculation. DRO but not AMIO exerted vasodilatory effects in coronary arteries and microcirculation, thus abolishing RAP-induced microvascular flow disturbances. These findings could help to explain the observed decrease in cardiovascular mortality seen with DRO administration in patients with AF.
- © 2011 by American Heart Association, Inc.