Cardiac Arrhythmias

Abstract

Modern experimental electrophysiology began earlier this century with the explanation of the basis of the action potential by Hodgkin and Huxley in the squid giant axon, and clinical cardiac electrophysiology with the development of the electrocardiogram by Einthoven. The fields continued to diverge in two rather independent directions. The development of intracellular electrodes, the voltage clamp, and the single-channel patch clamp revealed the subcellular events that underlie cardiac excitability and automaticity. Meanwhile, arrhythmia mapping, devices, and clinical trials have defined the mechanisms of the more common human arrhythmias and assessed the efficacy of therapeutic interventions. The advent of molecular biology has been invaluable to the understanding of channel biophysics during the last decade; the relation of single-channel properties to clinically relevant electrophysiology has lagged behind. The promise of molecular electrophysiology as a unifying element in the field is only now becoming apparent.