SUPPRESSION OF VENTRICULAR OUTPUT BY NOISE IN THE ATRIAL CHANNEL IN DUAL-CHAMBER PACEMAKER

In a pacemaker dependent, 60-year-old man with complete heart block, p rogramming high (5.0 V and 1.0 ms) atrial output and 5.0 volt and 0.5 ms ventricular output while in the DDD mode of a pulse generator, resu lted in loss of ventricular channel output with resulting asystole, wh ile the simultaneous, pulse generator produced ECG interpretation chan nel falsely indicated continuing ventricular channel output. Ventricul ar pacing was promptly restored by programming to the emergency VVI mo de. At later operation the atrial lead was determined to be defective, with a low impedance, while the ventricular lead was intact (lead imp edance telemetry was not available). The manufacturer has acknowledged a pulse generator design anomaly that may occur in the setting of a l ow atrial impedance and issued a Health Safety Alert.