Post-mortem evaluation of 415 pacemakers: in situ measurements and bench tests

AIM: The hypothesis was that there is more undetected dysfunction of implanted pacemaker systems than that detected and corrected. This prompted a research project (sponsored by the German Research Foundation) to detect pacemaker abnormalities and evaluate their complications for patients, thus, proving or disproving the hypothesis. METHODS AND RESULTS: Four hundred and fifteen pacemakers of deceased patients were analyzed assessing their functionality by in situ measurements and bench tests including five measurements and one telemetric interrogation. Results were divided into four categories and statistically evaluated. Life-threatening abnormalities were found in 3.8%, potentially life-threatening in 3.7%, probably symptomatic, divided into atrial and ventricular problems, 13.3% and 2.8%, respectively, and premature exhaustion in 1.2%. Three of 179 bipolar ventricular leads and 2 of 131 bipolar atrial leads had insulation defects corresponding to 1.7% and 1.5%, respectively. The bipolar complication rate was 2.8 times higher than unipolar. CONCLUSION: The pacemaker patients investigated, living 4 years with their pacemaker on average, had a post-mortem evaluated complication rate of the category "life-threatening" of 3.8%. This result corresponds to an annual complication rate of 0.94% compared with a rate of only 0.39% in an earlier investigation.