Analyzing and Managing Abnormal Heart Rhythms

Abstract

Cardiac arrhythmias (abnormal heart rhythms) can be life-threatening or simply annoying. Implantable pacemakers were introduced around 1960 to treat slow heart rates that might cause a patient to faint. Sudden cardiac death is usually due to ventricular fibrillation, a very fast chaotic heart rhythm that immobilizes the heart. External defibrillators were used in CCUs, but most patients who experience sudden death are not in hospitals. The introduction of automatic implantable cardiac defibrillators (ICDs) in the mid-1980s provided a safety net for patients at high risk for sudden death. These heart rhythm technologies were expensive, and concerns were raised about their costs and appropriate use. During the final quarter of the century, catheter-based diagnostic techniques were developed to evaluate patients with known or suspected arrhythmias. Cardiologists who focused on heart rhythm disorders were known as electrophysiologists. The emergence of clinical cardiac electrophysiology is an example of continuing subspecialization within cardiology.