Narrow QRS is not the Right Substrate for Cardiac Resynchronization Therapy
The physiologic underpinning for cardiac resynchronization therapy (CRT) began with Carl Wiggers in 1925. He showed that when contraction of the heart was induced by direct cardiac electrical stimulation, the early phase of contraction of the heart was slowed and myocardial tension developed more gradually.1 Wiggers explained these findings by differences in the order of excitation of the ventricle. Subsequent studies by a number of investigators highlighted the fact that a left bundle branch block conduction pattern was associated with dyssynchronous contraction that exacerbated left ventricular systolic dysfunction. Few people appreciate the fact that Dr. Morton Mower who was involved in the development of the implantable cardioverter defibrillator 2, 3 also developed the patent for cardiac resynchronization therapy in 19904 that was assigned to CPI/Guidant and subsequently licensed to Medtronic.
- Received January 27, 2013.
- Accepted January 28, 2013.
- Copyright © 2013, Circulation