The T Deflection of Isolated Mammalian Heart Muscle Electrogram
Both bipolar and unipolar electrograms recorded from well-oxygenated isolated papillary muscle preparations consist of R and T deflections in the same direction. The T is inverted by anoxia, rapid late, and injury. When cut linear strips of ventricular muscle are observed for many hours, during which time they presumably recover from the initial injury, the T deflection becomes upright in most cases, and then can be depressed and inverted by anoxia or rapid rates of stimulation. Since, in the absence of modifying factors, the T is in the same direction as the R deflection in a simple linear strip, it probably cannot be adequately explained on the basis of membrane repolarization. Since the nerve after-potentials are believed to represent processes involving oxidative metabolism, the T deflection may also be produced by metabolic processes, although the possibility cannot be excluded that it represents a combination of membrane repolarization and other processes.
- Received October 18, 1952.
- © 1953 American Heart Association, Inc.