Reliability of evoked endocardial T-wave sensing in 1,500 pacemaker patients.

Intracardiac measurements of the evoked endocardial T-wave were performed on 1,500 pacemaker patients. The sensed evoked T-wave amplitude was found to be above 0.75 mV in 94.1 percent of all cases. No correlation was found between the amplitude of the spontaneous R-wave and that of the evoked T-wave. Some electrode characteristics proved to be more favorable than others for evoked endocardial wave sensing, i.e., a surface area of less than 12 mm2, porous surface structure (preferably carbon), and atraumatic fixation.