A Method for Simultaneous Epicardial Monophasic Action Potential Recordings from the Dog Heart in Situ

Abstract

To record epicardial monophasic action potentials (MAP) simultaneously from different regions of intact beating hearts, a tripodal suction electrode device (total weight 1.5 g, distance between the flexible silicone legs 25 mm) was developed and tested in pentobarbital anesthetized open chest dogs. The device was easy to apply and gave stable and reproducible recordings. Repolarization times for epicardial left ventricular and endocardial right ventricular MAP correlated well (r = 0.97, P < 0.001). There was no correlation between MAP amplitude and repolarization times. The .beta.1-adrenergic agonist prenalterol decreased MAP duration, while the new class III antiarrhythmic drug melperone increased MAP duration. Mild ischemia effected MAP prolongation and severe ischemia MAP shortening, compared to simultaneous recordings from non-ischemic ventricular regions. Evidently the new tripodal suction electrode is a simple device for simultaneous recording of multiple MAP. The method should be suitable for studies of electrophysiological effects of drugs and other interventions in intact beating hearts.