WHEN PACEMAKERS FAIL - AN ANALYSIS OF CLINICAL PRESENTATION AND RISK IN 120 PATIENTS WITH FAILED DEVICES

Although pacemaker recalls are common, the optimal mechanism for risk assessment and triage of patients at risk for sudden loss of device sy stem function is unknown. A retrospective chart review of 120 patients with factory proven failed devices was performed. Logistic regression analysis was used to determine clinical correlates of emergency room versus outpatient clinic presentation at time of device failure. Twent y-two patients (18%) presented to emergency and 98 (82%) to clinic. Si xty-three devices had no device output at the time of presentation. Mu ltivariate logistic regression analysis revealed that antiarrhythmic d rug use (odds ratio: 7.4, 95% CI: 2.0-28.0), atrioventricular nodal di sease as an indication for pacing (odds ratio: 2.8, 95% CI: 1.2-3.0), and female gender (odds ratio: 2.2, 95% CI: 1.0-4.5) were the only sig nificant correlates of emergency room presentations. Pacemaker depende ncy (escape heart rate < 40 beats/min) did not correlate with location of presentation even though no device output at the time of presentat ion was associated with emergency room presentation (odds ratio: 2.5, 95% CI: 1.1-5.8). Neither the presence of structural heart disease nor symptoms at the time of device implantation (syncope or presyncope) w ere correlated with location of presentation upon unexpected device fa ilure. Although there were no deaths in the 120 failed devices studied , there were 26 deaths in the total group of 227 patients with recalle d devices that could not be studied. Antiarrhythmic drug use, electroc ardiographic pacing indication, and female gender may be more sensitiv e predictors of emergency room presentation and significant symptoms i n the event of unanticipated pacemaker failure. The inability of any r etrospective analysis to accurately assess mortality in the setting of pacemaker system failure underscores the need for prospective databas es in recall situations.