Transmembrane Voltage Changes Produced by Real and Virtual Electrodes During Monophasic Defibrillation Shock Delivered by an Implantable Electrode

Langendorff-perfused rabbit hearts (n = 12) stained with di-4-ANEPPS

Monophasic anodal and cathodal pulses (leading-edge voltage 50 to 150 V, pulse duration 10 msec) delivered by an internal transvenous implantable cardioverter defibrillator (ICD) lead during the plateau phase of an action potential or during ventricular fibrillation

Normal action potential (AP)

Transmembrane voltage changes (difference between the AP affected by the shock and the normal AP) optically recorded from 256 sites on the anterior right ventricular epicardiumsurrogate