Active myocarditis stage was found to predict the recurrence of ventricular tachycardia (VT) in patients with myocarditis undergoing VT ablation, according to a study published in the Journal of the American College of Cardiology.
A total of 125 patients (mean age, 51 ± 14 years; 91% men; mean left ventricular ejection fraction, 52±9%) with myocarditis scheduled to undergo VT ablation were enrolled. The participants had a history of myocarditis, diagnosed with: endomyocardial biopsy (EMB; 59%), cardiac magnetic resonance (CMR; 90%), or both (50%). In this cohort, the first VT episode occurred at a median of 5 months (interquartile range [IQR], 0-11 months) following myocarditis diagnosis.
A total of 47 patients (38%) had active myocarditis, and 78 patients (62%) had previous myocarditis, as assessed with multimodal preprocedural staging. The study’s primary endpoint was assessment of VT recurrences at the 12-month follow-up.
VT recurrences were documented in 25 patients (20%) at 12 months, and in 43 participants (34%) at the last follow-up (median, 63 months; IQR, 39-87). Active myocarditis stage was found to be the only predictor of VT recurrences at 12 months (hazard ratio, 9.5; 95% CI, 2.6-35.3; P <.001), and the active myocarditis stage and wide border zone were found to be associated with arrhythmia recurrences at any time during the follow-up period in multivariable analyses. No VT episodes were observed after redo ablation was performed in 23 patients during the previous myocarditis stage.
Study limitations include its single-center and retrospective design, the fact that myocarditis diagnosis was not uniformly based on EMB, and that different techniques were used to determine disease stage.
“Consistently, our exploratory analysis of a large number of candidate predictors identified active inflammatory status as the only predictor of VT recurrences by 12-month follow-up,” the investigators commented. “Our findings suggest that accurate disease staging, either through EMB or second-level imaging, should be performed before scheduling VT ablation in patients with myocarditis. As possible, the procedure should be reserved to the previous myocarditis cases, and otherwise deferred until the resolution of active inflammation. Among procedure-related risk factors, we found a significant association between wide border zone and VT recurrences any time during follow-up.”
Peretto G, Sala S, Basso C, et al. Inflammation as a predictor of recurrent ventricular tachycardia after ablation in patients with myocarditis. J Am Coll Cardiol. 2020;76(14):1644-1656.