R-wave triggering of external instrumentation during cardiac pacing

Monitoring and diagnostic instruments often utilize electrocardiographic R-wave detection for measuring heart rate or for timing of measurement processes. During cardiac pacing stimulus artifacts commonly interfere with the operation of such instruments because they are misinterpreted as R-waves. This phenomenon creates problems in assessing the hemodynamics during gated blood-pool scans, coronary care monitoring, and intra-aortic balloon pumping. A straightforward solution is found in the nature of the electrical signals involved in which the stimulus artifacts are detected independently and are removed from the signal fed to the R-wave detector.