Normally, the left and right ventricles — the lower chambers of the heart — contract at the same time. Heart failure can disturb the heart's normal electrical pathway, causing uncoordinated, "asynchronous" pumping of the ventricles, further decreasing the heart's ability to properly pump blood. This defect of the heart's electrical system is called left bundle branch block and is common in patients with congestive heart failure.
The biventricular pacemaker has three leads, one for the right atrium, one for the right ventricle and one that is placed in a vein on the surface of the left ventricle. The biventricular pacemaker stimulates the ventricles to contract together. This treatment is called cardiac resynchronization therapy (CRT). When coupled with a defibrillator, this therapy is called cardiac resynchronization therapy with a defibrillator or CRT-D.
At UChicago Medicine, electrophysiologists work side-by-side with the heart failure care team to identify patients who may benefit from cardiac resynchronization therapy. Over 70 percent of patients who are candidates for CRT can expect to see benefits including an improvement in symptoms, less heart failure hospitalizations, better quality of life and longer survival rate.