Sex differences in the prognosis of nonsustained ventricular tachycardia detected on Holter recording

Background: Nonsustained ventricular tachycardia (NSVT) is a common finding during cardiac evaluation and has been linked to increased mortality. While some studies report a sex difference, most data stem from research cohorts. Objective: This study aimed to assess the prognostic significance of NSVT in a real-life outpatient clinic, focusing on sex differences in mortality. Methods: Analysis was performed on a cohort of consecutive patients referred to 48-hour Holter monitoring between 2009 and 2011 at Copenhagen University Hospital - Bispebjerg. Indications for Holter monitoring included palpitations, dizziness, syncope, or arrhythmia testing. Baseline characteristics, blood tests, echocardiography results, and mortality data were obtained from electronic patient records. Results: A total of 762 females (mean age 59 ± 18 years) and 693 males (mean age 59 ± 17 years) were enrolled. At least 1 episode of NSVT was detected in 9.7% of females and 20.6% of males. The median follow-up was 8.3 years. A total of 20% of females and 24% of males died during follow-up. In multivariable models, NSVT was linked to mortality in males (hazard ratio [HR] 1.6, 95% confidence interval [CI] 1.1-2.3) but not in females (HR 1.2, 95% CI 0.7-2.1). In case-control pairs matched on the propensity of being male conditional on relevant risk factors, NSVT was again linked to mortality in males (HR 3.1, 95% CI 2.0-4.8) but not in females (HR 1.4, 95% CI 0.8-2.4). Conclusion: In consecutive patients referred to symptom driven Holter monitoring, NSVT was associated with elevated all-cause mortality in males but not in females. These results can contribute to the risk assessment of patients presenting with NSVT.