Barts Heart Center, St Bartholomew's Hospital, Barts Health NHS Trust, London, United Kingdom (J.W.M., R.K.H., T.H., M.L., J.C.M., L.R.L., C.O.M., N.S., P.M.E., S.E.P., M.B.D., S.A.M.).
William Harvey Research Institute, NIHR Barts Biomedical Research Centre, Queen Mary University of London, United Kingdom (J.W.M., K.K., A.E.L., S.E.P., S.A.M.).
Circ Arrhythm Electrophysiol. 2024 Jul;17(7):e012570. doi: 10.1161/CIRCEP.123.012570. Epub 2024 Jun 19.
Patients with refractory, symptomatic left ventricular (LV) mid-cavity obstructive (LVMCO) hypertrophic cardiomyopathy have few therapeutic options. Right ventricular pacing is associated with modest hemodynamic and symptomatic improvement, and LV pacing pilot data suggest therapeutic potential. We hypothesized that site-specific pacing would reduce LVMCO gradients and improve symptoms.
Patients with symptomatic-drug-refractory LVMCO were recruited for a randomized, blinded trial of personalized prescription of pacing (PPoP). Multiple LV and apical right ventricular pacing sites were assessed during an invasive hemodynamic study of multisite pacing. Patient-specific pacing-site and atrioventricular delays, defining PPoP, were selected on the basis of LVMCO gradient reduction and acceptable pacing parameters. Patients were randomized to 6 months of active PPoP or backup pacing in a crossover design. The primary outcome examined invasive gradient change with best-site pacing. Secondary outcomes assessed quality of life and exercise following randomization to PPoP.
A total of 17 patients were recruited; 16 of whom met primary end points. Baseline New York Heart Association was 3±0.6, despite optimal medical therapy. Hemodynamic effects were assessed during pacing at the right ventricular apex and at a mean of 8 LV sites. The gradients in all 16 patients fell with pacing, with maximum gradient reduction achieved via LV pacing in 14 (88%) patients and right ventricular apex in 2. The mean baseline gradient of 80±29 mm Hg fell to 31±21 mm Hg with best-site pacing, a 60% reduction (<0.0001). One cardiac vein perforation occurred in 1 case, and 15 subjects entered crossover; 2 withdrawals occurred during crossover. Of the 13 completing crossover, 9 (69%) chose active pacing in PPoP configuration as preferred setting. PPoP was associated with improved 6-minute walking test performance (328.5±99.9 versus 285.8±105.5 m; =0.018); other outcome measures also indicated benefit with PPoP.
In a randomized placebo-controlled trial, PPoP reduces obstruction and improves exercise performance in severely symptomatic patients with LVMCO.
URL: https://clinicaltrials.gov/study; Unique Identifier: NCT03450252.
患有难治性、有症状的左心室（LV）中段梗阻（LVMCO）肥厚型心肌病的患者治疗选择有限。右心室起搏与适度的血液动力学和症状改善相关，而 LV 起搏的初步数据表明具有治疗潜力。我们假设特定部位起搏将降低 LVMCO 梯度并改善症状。
招募了患有症状性药物难治性 LVMCO 的患者，进行一项个性化起搏处方（PPoP）的随机、双盲试验。在多部位起搏的侵入性血液动力学研究中评估了多个 LV 和心尖右心室起搏部位。根据 LVMCO 梯度降低和可接受的起搏参数选择患者特定的起搏部位和房室延迟，定义 PPoP。患者按交叉设计随机分为 6 个月的主动 PPoP 或后备起搏。主要终点是评估最佳部位起搏时的侵入性梯度变化。次要终点是随机分组后评估生活质量和运动情况。
共招募了 17 名患者，其中 16 名符合主要终点。尽管接受了最佳药物治疗，但基线纽约心脏协会（NYHA）评分为 3±0.6。在右心室心尖部和平均 8 个 LV 部位起搏时评估血液动力学效应。16 名患者的所有梯度均随起搏而降低，14 名（88%）患者通过 LV 起搏和 2 名通过右心室心尖部起搏达到最大梯度降低。最佳部位起搏时，平均基线梯度 80±29mmHg 降至 31±21mmHg，降低 60%（<0.0001）。1 例发生心静脉穿孔，15 例进入交叉期；交叉期有 2 例退出。13 例完成交叉的患者中，有 9 例（69%）选择主动起搏作为 PPoP 配置的首选设置。PPoP 与 6 分钟步行试验表现的改善相关（328.5±99.9 与 285.8±105.5 m；=0.018）；其他终点指标也表明 PPoP 有益。
在一项随机安慰剂对照试验中，PPoP 可减轻严重 LVMCO 症状患者的梗阻并改善运动能力。
