Arrhythmia Unit and Electrophysiology Laboratories, IRCCS San Raffaele Scientific Institute, Milano, Italy.
Applied Diagnostic Echocardiography Unit, IRCCS Humanitas Clinical and Research Center, Milan, Italy.
J Cardiovasc Electrophysiol. 2021 Dec;32(12):3179-3186. doi: 10.1111/jce.15270. Epub 2021 Oct 28.
Myxomatous mitral valve prolapse (MVP) and mitral-annular disjunction (Barlow disease) are at-risk for ventricular arrhythmias (VA). Fibrosis involving the papillary muscles and/or the infero-basal left ventricular (LV) wall was reported at autopsy in sudden cardiac death (SCD) patients with MVP.
We investigated the electrophysiological substrate subtending VA in MVP patients with Barlow disease phenotype.
Twenty-three patients with VA were enrolled, including five with syncope and four with a history of SCD. Unipolar (Uni < 8.3 mV) and bipolar (Bi < 1.5 mV) low-voltage areas were analyzed with electro-anatomical mapping (EAM), and VA inducibility was evaluated with programmed ventricular stimulation (PES). Electrophysiological parameters were correlated with VA patterns, electrocardiogram (ECG) inferior negative T wave (nTW), and late gadolinium enhancement (LGE) assessed by cardiac magnetic resonance.
Premature ventricular complex (PVC) burden was 12 061.9 ± 12 994.6/24 h with a papillary-muscle type (PM-PVC) in 18 patients (68%). Twelve-lead ECG showed nTW in 12 patients (43.5%). A large Uni less than 8.3 mV area (62.4 ± 45.5 cm ) was detected in the basal infero-lateral LV region in 12 (73%) patients, and in the papillary muscles (2.2 ± 2.9 cm ) in 5 (30%) of 15 patients undergoing EAM. A concomitant Bi less than 1.5 mV area (5.0 ± 1.0 cm ) was identified in two patients. A history of SCD, and the presence of nTW, and LGE were associated with a greater Uni less than 8.3 mV extension: (32.8 ± 3.1 cm vs. 9.2 ± 8.7 cm ), nTW (20.1 ± 11.0 vs. 4.1 ± 3.8 cm ), and LGE (19.2 ± 11.7 cm vs. 1.0 ± 2.0 cm , p = .013), respectively. All patients with PM-PVC had a Uni less than 8.3 mV area. Sustained VA (ventricular tachycardia 2 and VF 2) were induced by PES only in four patients (one with resuscitated SCD).
Low unipolar low voltage areas can be identified with EAM in the basal inferolateral LV region and in the papillary muscles as a potential electrophysiological substrate for VA and SCD in patients with MVP and Barlow disease phenotype.
黏液样二尖瓣脱垂（MVP）和二尖瓣-瓣环分离（Barlow 病）易发生室性心律失常（VA）。尸检报道，MVP 合并心脏性猝死（SCD）患者的乳头肌和/或下基底部左心室（LV）壁存在纤维化。
我们研究了 MVP 伴 Barlow 病表型患者 VA 的电生理基质。
共纳入 23 例 VA 患者，其中 5 例有晕厥，4 例有 SCD 病史。采用电解剖标测（EAM）分析单极（Uni < 8.3 mV）和双极（Bi < 1.5 mV）低电压区，并采用程控心室刺激（PES）评估 VA 诱发性。电生理参数与 VA 模式、心电图（ECG）下壁负性 T 波（nTW）和心脏磁共振评估的晚期钆增强（LGE）相关。
24 小时内 PVC 负荷为 12 061.9 ± 12 994.6/24 小时，18 例（68%）患者为乳头肌型（PM-PVC）。12 导联心电图显示 12 例（43.5%）患者有 nTW。12 例（73%）患者下基底部外侧 LV 区域检测到较大的 Uni < 8.3 mV 面积（62.4 ± 45.5 cm ），而 5 例（30%）患者在乳头肌中检测到 2.2 ± 2.9 cm 的 Uni < 8.3 mV 面积。在 2 例患者中发现了同时的 Bi < 1.5 mV 面积（5.0 ± 1.0 cm ）。SCD 病史、nTW 和 LGE 的存在与更大的 Uni < 8.3 mV 延伸相关：（32.8 ± 3.1 cm 与 9.2 ± 8.7 cm ）、nTW（20.1 ± 11.0 与 4.1 ± 3.8 cm ）和 LGE（19.2 ± 11.7 cm 与 1.0 ± 2.0 cm ，p = 0.013）。所有 PM-PVC 患者均有 Uni < 8.3 mV 面积。PES 仅诱导 4 例患者（1 例为 SCD 复苏）持续性 VA（室性心动过速 2 例和 VF 2 例）。
EAM 可在下基底部外侧 LV 区域和乳头肌中识别到低单极低电压区，可能是 MVP 伴 Barlow 病表型患者 VA 和 SCD 的潜在电生理基质。
