Comparative effects of amiodarone, bepridil and perhexiline on coronary venous flow and several cardiovascular parameters.

The effects of amiodarone (10 mg/kg i.v.), bepridil (2.5 mg/kg i.v.) and perhexiline (2.5 mg/kg i.v.) were compared in the anesthetized dog at doses inducing a decrease in heart rate of same intensity. This bradycardial effect existed for amiodarone and bepridil whether the heart was denervated or not. Perhexiline did not modify the rate of the denervated heart. Amiodarone decreased dp/dt max whether the heart was denervated, innervated or paced at constant rate. PO2 in coronary venous blood was transiently increased with no significant variations in coronary flow. Bepridil reduced dp/dt max only after cardiac denervation; coronary PVO2 was increased in a durable way although the rise in coronary flow did not exceed a few minutes. Perhexiline decreased dp/dt max in a durable way only when cardiac innervation was respected. It had no effect on coronary flow. The increase in coronary PVO2 was transient and depended upon bradycardia.