Description of Event or Problem · 1
A MAN HAD UNDERGONE ROUTINE CAROTID ENDARTERECTOMY AND WAS BEING MONITORED POSTOPERATIVELY IN AN ICU SETTING. SIX MONTHS BEFORE HE HAD RECEIVED A ST. JUDE INTEGRITY ADX DR 5360 DUAL-CHAMBER PACEMAKER AT ANOTHER HOSP. HE HAD A HISTORY OF PREVIOUS CORONARY BYPASS SURGERY, HYPERTENSION AND ABDOMINAL AORTIC ANEURYSM RESECTION. WHILE ON MONITOR HE SUDDENLY BECAME UNRESPONSIVE AND VENTRICULAR FIBRILLATION WAS SEEN. CPR MEASURES INCLUDING CHEST COMPRESSIONS COMMENCED AND WERE CONTINUED FOR APPROX 90 SECONDS AS A DEFIBRILLATOR WAS BEING BROUGHT INTO PLACE. VENTRICULAR FIBRILLATION CEASED SPONTANEOUSLY, DUAL CHAMBER PACING RESUMED AND HE MADE A FULL RECOVERY. ANALYSIS OF STORED MONITOR STRIP (SEE FIGURE) REVEALED DUAL CHAMBER PACING WITH AN EARLY UNSENSED VENTRICULAR COMPLEX. ATRIAL PACING WAS DELIVERED INTO THIS COMPLEX FOLLOWED BY VENTRICULAR PACING AT PROGRAMMED AV INTERVAL. THIS PACING SPIKE FELL INTO THE ST SEGMENT OF THE PVC AND DID NOT CAPTURE. THIS WAS FOLLOWED BY AN "AUTOCAPTURE" VENTRICULAR PACING SPIKE AT A 90 MSEC DELAY WHICH PACED ON THE PEAK OF THE T WAVE OF THE PVC, LEADING TO SUSTAINED VENTRICULAR FIBRILLATION. INTERROGATION OF THE PACER SHOWED APPROPRIATE FUNCTION: SENSED INTRINSIC R WAVES OF 9 MV WERE SEEN WITH PACER SENSITIVITY HAVING BEEN PROGRAMMED TO 2 MV. CAPTURE THRESHOLDS IN BOTH CHAMBERS WERE LESS THAN 1.0V WITH NORMAL IMPEDANCES. THE PACER WAS REPROGRAMMED, INCREASING VENTRICULAR SENSITIVITY TO 1 MV, AND AUTOCAPTURE WAS TURNED OFF. THE PT HAS MADE AN UNEVENTFUL RECOVERY. DISCUSSION: NORMALLY FUNCTIONING AUTOCAPTURE FEATURE OF ST. JUDE PACEMAKERS MAY LEAD TO SUDDEN DEATH. THIS FEATURE SHOULD BE PROGRAMMED OFF IN ALL SUCH DEVICES. OTHER MFRS SHOULD REVIEW CAREFULLY THE POTENTIAL RISKS OF SIMILAR AUTO CAPTURE FEATURES DESIGNED TO INCREASE PACER BATTERY LIFE. [SEE SCANNED PAGE.]