[Acute and chronic threshholds in epicardial stimulation of the diaphragmatic surface of the right ventricle].

Between March 1974, and November 1979, a total of 244 epicardial electrodes, 29 in the anterior surface and 215 in the right ventricular diaphragmatic surface (RVDS) were implanted using the 212 a left subcostal approach. In 174 consecutive patients (mean age 64 years) a preoperative epicardial electrophysiological study was made (mapping), with measurement of voltage, current, lead impedance and R wave sensing in different zones of right ventricle. A comparative study between two types of sutureless electrodes was realized. In 21 cases, thresholds chronic measurement was made 32 months after implantation. There were one surgical death (0.4%) with a morbidity of 7.4%. The follow-up is 20 months mean. The mapped group has significantly lower thresholds and better sensing than the unmapped group (p 0.001). Chronic thresholds were obtained at pacemaker replacement in 21 cases (average 32 months postimplant) and were much lower in the mapped group. These are in line with the acute studies.