BACKGROUND Ventricular arrhythmias (VAs) have never been systematically investigated in patients with myocarditis at different stages. OBJECTIVES The purpose of this study was to compare baseline and follow-up characteristics of VAs in patients with active myocarditis (AM) versus previous myocarditis (PM). METHODS A total of 185 consecutive patients (69% males, age 44 ± 15 years, left ventricular ejection fraction 49 ± 14%) with myocarditis and VA at index hospitalization, including ventricular fibrillation, ventricular tachycardia (VT), nonsustained ventricular tachycardia (NSVT), and Lown's grade ≥2 premature ventricular complexes, were enrolled. AM and PM groups were defined based on endomyocardial biopsy and cardiac magnetic resonance findings. A subset of patients (n = 46, 25%) also underwent electroanatomic mapping and VA transcatheter ablation. RESULTS At presentation, AM patients (n = 123, 66%) more commonly had ventricular fibrillation (8 cases vs. 0 cases; p = 0.053), and both irregular (61% vs. 11%; p < 0.001) and polymorphic VA (NSVT and VT: 19% vs. 2%; p = 0.002; premature ventricular complexes: 63% vs. 16%; p < 0.001). Only in PM patients with NSVT or VT, the dominant morphology (right-bundle branch block with superior axis) was 100% predictive of abnormal LV inferoposterior substrate at both cardiac magnetic resonance and electroanatomic mapping. At 27 ± 7 months prospective follow-up, 55 patients (30%) experienced malignant VA (AM vs. PM, p = 0.385). Although a prevalence of polymorphic and irregular VA was confirmed in AM patients with persistent inflammation in follow-up (58%), a predominance of monomorphic and regular VA was found in AM patients after myocarditis healing (42%), as well as in PM patients (all p < 0.001). CONCLUSIONS In myocarditis patients, polymorphic and irregular VA are more common during the active inflammatory phase, whereas monomorphic and regular VA are associated with healed myocarditis.

中文翻译：

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心肌炎中的室性心律失常

背景 室性心律失常 (VA) 从未在不同阶段的心肌炎患者中进行过系统研究。目的 本研究的目的是比较活动性心肌炎 (AM) 与既往心肌炎 (PM) 患者 VA 的基线和随访特征。方法 共有 185 名连续住院患者（69% 男性，年龄 44 ± 15 岁，左心室射血分数 49 ± 14%）在住院时患有心肌炎和 VA，包括心室颤动、室性心动过速 (VT)、非持续性室性心动过速 (NSVT) ) 和 Lown 分级≥2 的室性早搏。AM 和 PM 组是根据心内膜心肌活检和心脏磁共振结果定义的。患者子集（n = 46，25%) 还接受了电解剖标测和 VA 经导管消融。结果 就诊时，AM 患者（n = 123, 66%）更常见心室颤动（8 例 vs. 0 例；p = 0.053），以及不规则（61% vs. 11%；p < 0.001）和多形性 VA （NSVT 和 VT：19% 与 2%；p = 0.002；室性早搏：63% 与 16%；p < 0.001）。只有在患有 NSVT 或 VT 的 PM 患者中，主要形态（具有上轴的右束支传导阻滞）在心脏磁共振和电解剖标测中都能 100% 预测异常 LV 后底物。在 27 ± 7 个月的前瞻性随访中，55 名患者 (30%) 经历了恶性 VA（AM 与 PM，p = 0.385）。尽管在随访中证实存在持续炎症的 AM 患者中存在多形性和不规则 VA 的患病率 (58%)，心肌炎愈合后的 AM 患者 (42%) 以及 PM 患者 (所有 p < 0.001) 中发现单形和规则 VA 占优势。结论 在心肌炎患者中，多形性和不规则性 VA 在活动性炎症期更常见，而单形性和规则性 VA 与治愈的心肌炎相关。