Prognosis of patients with wild-type transthyretin cardiac amyloidosis and non-sustained ventricular tachycardia.

Introduction: Little is known regarding the prevalence and prognostic implications of non-sustained ventricular tachycardia (NSVT) in patients with wild-type transthyretin cardiac amyloidosis (ATTRwt-CA). We aimed to investigate the prevalence of NSVT in patients with ATTRwr-CA, and the association of NSVT with sustained ventricular arrhythmias (VA) and all-cause mortality.

Methods: In a cohort of ATTRwt-CA patients from 2011 to 2022 without prior sustained VA, we ascertained the presence and characteristics of NSVT during clinically indicated ambulatory Holter monitoring. Patients were stratified based on the presence of NSVT at baseline. The primary and secondary endpoints of sustained VA and all-cause mortality, respectively, were assessed during follow-up.

Results: The cohort included 217 patients with ATTRwt-CA (95% males, median age 75 years; median NYHA class 2). Baseline Holter monitoring demonstrated NSVT in 116 (53%) patients. During a median follow-up of 27 months (IQR 16-45) after the index Holter monitor, 11 (5.1%) patients reached the primary endpoint of sustained VA (incidence 1.8 per 100 person-years, all monomorphic VT), and 46 (21%) patients died. In univariable Cox proportional hazard model, NYHA class 3 or 4 heart failure (p = .048), the presence of NSVT (p = .04), the duration of longest NSVT run (p = .029), and the percentage of ventricular ectopy (p < .001) were associated with the primary outcome. When adjusting for age and NYHA class 3 or 4 heart failure, the presence of NSVT remained associated with the primary outcome (p = .03). All-cause mortality was not significantly different between patients with and without NSVT. A cutoff for ventricular ectopy burden of 0.5%, the median for all patients in this study, was associated with increased risk in sustained VA (log-rank p = .004) and mortality (log-rank p = .02).

Conclusion: NSVT is highly prevalent among ATTRwt-CA patients undergoing clinically indicated Holter monitoring and may confer an increased risk of incident sustained VA.