Measurement of minute ventilation with different DDDR pacemaker electrode configurations. Investigators of a Multicenter Study Evaluating the Chorus RM and Opus RM Pacemakers.

A rate responsive minute ventilation (VE) pacemaker was implanted in 49 patients (70.8 +/- 40.0 years). A Chorus RM 7034 pacemaker was implanted in 43 patients and an Opus RM 4534 in six patients. Four sensor configurations were compared: atrial configuration (bipolar atrial lead) in 34 patients; ventricular configuration (bipolar ventricular lead) in 6 patients; unipolar configuration (double unipolar leads) in 6 patients; and floating configuration (VDD single-pass lead) in 3 patients. The patients carried out 57 exercise tests in all with cardiopulmonary recording (CPX). Real VE and oxygen consumption (VO2) were recorded by the CPX, the VE measured by the sensor (VEsensor) was recorded in the pacemaker memory. The mean correlation between VE and VEsensor was 0.90 +/- 0.08 (P < 0.001) and between VO2 and VEsensor was 0.86 +/- 0.10 (P < 0.001). The mean correlation between VE and VEsensor by configuration type were as follows: atrial configuration = 0.89 +/- 0.08; ventricular configuration = 0.95 +/- 0.05; unipolar configuration = 0.87 +/- 0.14; and floating configuration = 0.88 +/- 0.05. In conclusion, VE may be reliably measured using different electrode configurations. A study conducted in a larger population should allow one to conclude that unipolar electrodes can be used in VDDR, AAIR, VVIR, or DDDR modes to measure VE.