Clinical Significance of Nonsustained Ventricular Tachycardia on Routine Monitoring of Pacemaker Patients

Background Permanent pacemakers (PPMs) are capable of recording tachyarrhythmic events including nonsustained ventricular tachycardia (NSVT), though the clinical significance of NSVT on routine PPM evaluation is unknown. Our goals: assess the prevalence of NSVT on routine PPM follow-up and survival of PPM patients with NSVT, without NSVT, and with ventricular high rate (VHR) episodes of undefined origin. Methods A single-center retrospective, cohort study was performed on patients implanted with PPMs capable of recording NSVT, defined as ≥5 consecutive ventricular beats at ≥170/minutes lasting <30 seconds. Patients were categorized: (1) no NSVT; (2) NSVT; or (3) VHR episodes of uncertain etiology. The primary endpoint was all-cause mortality within 6 months of last follow-up. Results Note that in 1,125 enrollees (51.8% male, age 74.2 ± 15.5 years, ejection fraction 57.0 ± 9.0%), 742 (66%) had no NSVT, 223 had NSVT (20%), and 160 (14%) had VHR. There were no differences in ejection fraction, diabetes, hypertension, coronary disease, prior myocardial infarction, baseline creatinine, QRS duration, prevalence of left bundle branch block, or β-blocker use among groups. "No NSVT" patients were older (P = 0.013), NSVT patients had more males (P = 0.012); atrial fibrillation and digoxin use were more prevalent in VHR patients (P < 0.01). During median follow-up of 2.8 years there were 93 deaths within 6 months of last follow-up with no differences in survival among groups (log rank P = 0.47). Age, ejection fraction at time of implant, and β-blocker use were independent predictors of survival. Conclusion NSVT detected on routine PPM follow-up in this patient population with a preserved ejection fraction is not associated with long-term mortality.