Long-Term Outcome of Non-Sustained Ventricular Tachycardia in Structurally Normal Hearts

Abstract

Background: The impact of non-sustained ventricular tachycardia (NSVT) on the risk of thromboembolic event and clinical outcomes in patients without structural heart disease remains undetermined. This study aimed to evaluate the association between NSVT and clinical outcomes.

Methods: The study population of 5903 patients was culled from the "Registry of 24-hour ECG monitoring at Taipei Veterans General Hospital" (REMOTE database) between January 1, 2002 and December 31, 2004. Of that total, we enrolled 3767 patients without sustained ventricular tachycardia, structural heart disease, and permanent pacemaker. For purposes of this study, NSVT was defined as 3 or more consecutive beats arising below the atrioventricular node with an RR interval of <600 ms (>100 beats/min) and lasting < 30 seconds.

Result: There were 776 deaths, 2042 hospitalizations for any reason, 638 cardiovascular (CV)-related hospitalizations, 350 ischemic strokes, 409 transient ischemic accident (TIA), 368 new-onset heart failure (HF), and 260 new-onset atrial fibrillation (AF) with a mean follow-up duration of 10 ± 1 years. In multivariate analysis, the presence of NSVT was independently associated with death (hazard ratio [HR]: 1.362, 95% confidence interval [CI]: 1.071-1.731), CV hospitalization (HR: 1.527, 95% CI: 1.171-1.992), ischemic stroke (HR: 1.436, 95% CI: 1.014-2.032), TIA (HR 1.483, 95% CI: 1.069-2.057), and new-onset HF (HR: 1.716, 95% CI: 1.243-2.368). There was no significant association between the presence of NSVT and all-cause hospitalization or new-onset AF.

Conclusion: In patients without structural heart disease, presence of NSVT on 24-hour monitoring was independently associated with death, CV hospitalization, ischemic stroke, TIA, and new onset heart failure.

Fig 1. Kaplan-Meier curve of survival by presence of NSVT.

Panel A shows Kaplan-Meier survival curve in patients with or without NSVT. Panel B shows Kaplan-Meier curve of CV hospitalization-free survival in patients with or without NSVT. Panel C shows Kaplan-Meier curve of stroke-free survival in patients with or without NSVT. Panel D shows Kaplan-Meier curve of occurrence of new-onset HF free survival in patients with or without NSVT. CV indicates cardiovascular; CVA, cerebral vascular accident; HF, heart failure; NSVT, non-sustained ventricular tachycardia.

Fig 2. Forest plot for subgroup analysis for all-cause mortality.

The hazard ratios of NSVT in comparison with no NSVT in different subgroups of patients with individual risk factors. CI indicates confident interval; CKD, chronic kidney disease; DM, diabetes mellitus; HTN, hypertension; NSVT, non-sustained ventricular tachycardia. *P value for the NSVT by each stratification variables interaction.