While most serious issues related to heart rhythm disturbances occur in the heart’s upper chambers, or atria, sometimes they do occur in the lower chambers, the ventricles, which are the main pumping chambers. This can cause a very rapid heartbeat called ventricular tachycardia. It’s usually caused by scarring from a heart attack or other issues such as inflammation. Generally some muscle fibers survive the scarring caused by a heart attack. When the fibers generate electrical impulses as all muscles do, they create havoc in the heart’s electrical system.

In this white board session, Patrick J. Tchou, MD, Associate Section Head of the Section of Electrophysiology and Cardiac Pacing in the Department of Cardiovascular Medicine, explains how excessively fast rates in the lower chambers can affect the heart’s ability to pump blood — which can cause major issues.