Departments of Cardiovascular Medicine and Internal Medicine (Clinician-Investigator Training Program), Mayo Clinic, Rochester, MN, United States of America.
Department of Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), Mayo Clinic, Rochester, MN, United States of America.
Int J Cardiol. 2019 Jan 1;274:175-178. doi: 10.1016/j.ijcard.2018.09.046. Epub 2018 Sep 11.
Mitral valve prolapse (MVP), including the recently described arrhythmogenic bileaflet MVP syndrome (ABiMVPS), is associated with repolarization abnormalities and may represent an underestimated cause of sudden cardiac death. The impact of concomitant MVP or ABiMVPS on long QT syndrome (LQTS) clinical severity is unknown.
Retrospective review of 754 LQTS patients [445 females (58%) and mean QTc 471 ± 41 ms] with available echocardiographic data was performed to identify LQTS patients with not only MVP, but also a pro-arrhythmic ABiMVPS phenotype defined as bileaflet MVP, inferolateral T-wave inversions, and frequent complex ventricular ectopy/arrhythmia. As expected, 18/754 (2%) LQTS patients had concomitant MVP. Of these, 5/18 (28%) LQTS patients with MVP satisfied ABiMVPS diagnostic criteria. No difference in symptomatology, degree of QT prolongation, or clinical management was observed between LQTS patients with and without MVP. In contrast, LQTS plus ABiMVPS resulted in a severe cardiac phenotype as illustrated by symptomatic status (LQTS-ABiMVPS; 5/5; 100%; vs LQTS: 279/736; 39%; p = .008), degree of baseline QTc prolongation (LQTS-ABiMVPS: 536 ± 58 ms; vs LQTS: 470 ± 40 ms; p = .009), and number of patients experiencing ≥1 on-therapy break-through cardiac event (LQTS-ABiMVPS: 4/5; 80%; vs LQTS: 48/736; 7%; p < .001]. Lastly, individuals with LQTS plus ABiMVPS were more likely to experience appropriate ICD therapies post-cardiac denervation (LQTS-ABiMVPS: 2/3; 67% vs LQTS: 4/49; 8%; p = .03].
The co-existence of LQTS and ABiMVPS may lead to a rare, but malignant, clinical entity characterized by potentially life-threatening arrhythmias despite maximal LQTS therapy.
二尖瓣脱垂（MVP），包括最近描述的心律失常性双瓣叶 MVP 综合征（ABiMVPS），与复极异常有关，可能是心脏性猝死的一个被低估的原因。同时存在 MVP 或 ABiMVPS 对长 QT 综合征（LQTS）临床严重程度的影响尚不清楚。
对 754 例 LQTS 患者（445 例女性[58%]，平均 QTc 471±41ms）进行回顾性分析，这些患者均有超声心动图数据，并确定不仅存在 MVP，而且还存在致心律失常的 ABiMVPS 表型的 LQTS 患者。ABiMVPS 表型定义为双瓣叶 MVP、下外侧 T 波倒置和频繁出现复杂室性异位搏动/心律失常。如预期的那样，754 例 LQTS 患者中有 18 例（2%）同时存在 MVP。其中，18 例 MVP 患者中有 5 例（28%）符合 ABiMVPS 诊断标准。伴有或不伴有 MVP 的 LQTS 患者的症状、QT 延长程度或临床管理无差异。相比之下，LQTS 合并 ABiMVPS 导致严重的心脏表型，症状状态如图所示（LQTS-ABiMVPS：5/5；100%；与 LQTS：279/736；39%；p=0.008）、基线 QTc 延长程度（LQTS-ABiMVPS：536±58ms；与 LQTS：470±40ms；p=0.009）以及接受治疗时发生≥1 次突破性心脏事件的患者人数（LQTS-ABiMVPS：4/5；80%；与 LQTS：48/736；7%；p<0.001）。最后，LQTS 合并 ABiMVPS 的患者在心脏去神经支配后更有可能经历适当的 ICD 治疗（LQTS-ABiMVPS：2/3；67%；与 LQTS：4/49；8%；p=0.03）。
尽管进行了最大程度的 LQTS 治疗，但 LQTS 合并 ABiMVPS 可能导致一种罕见但恶性的临床实体，其特征为潜在危及生命的心律失常。
