Abstract
The RS4 pacemaker system, employs a tripolar single lead, can be programmed to operate as an atrial sensing, ventricular pacing pulse generajor (RS mode, VDD), or as a normal demand unit (VVI). In the RS mode, the pacinq rate can vary from 63ppm to 120ppm, depending on atrial activity. We used the system with 3 patients (far-advanced AV block; 1, 3rd degree AV block; 2). P wave amplitude measured by the bipolar floating atrial electrodes were from 2.7mV to 3.0mV. The pacing rate varied in response to exercise and a drug. In the points of double product and cardiac output, RS mode was recongnized to be physiologic rather than VVI pacing.
