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.