Cardiology Division, Massachusetts General Hospital, Boston, Massachusetts.
Electrophysiology Section, Cardiovascular Division, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania.
JACC Clin Electrophysiol. 2018 Feb;4(2):168-177. doi: 10.1016/j.jacep.2017.10.002. Epub 2017 Nov 15.
This study sought to determine the extent, time course, and predictors of improvement following cardiac resynchronization therapy (CRT) upgrade among pacing-induced cardiomyopathy (PICM) patients.
PICM is an important cause of heart failure in patients exposed to frequent right ventricular (RV) pacing. CRT may reverse PICM.
We retrospectively studied 1,279 consecutive patients undergoing CRT procedures between 2003 and 2016. Patients undergoing CRT upgrade from a dual-chamber or single-chamber ventricular pacemaker for PICM were included. PICM was defined as decrease of ≥10% in left ventricular ejection fraction (LVEF), resulting in LVEF <50% among patients experiencing ≥20% RV pacing without an alternative cause of cardiomyopathy. Severe PICM was defined as pre-upgrade LVEF ≤35%. Clinical, electrocardiographic, and echocardiographic characteristics associated with both the extent of LVEF recovery and with post-upgrade LVEF of >35% among those with severe PICM were identified.
Of 69 PICM patients, LVEF improved from 29.3% to 45.3% over a median 7.0 months. Of 54 patients with severe PICM, 39 (72.2%) improved to LVEF >35% over a median 7.0 months. Most improvement occurred within the first 3 months, although improvement continued over the remainder of the first year. In linear regression, narrower native QRS was associated with greater LVEF improvement following CRT upgrade (+2.00% per 10-ms decrease; p = 0.05).
CRT is highly efficacious in reversing PICM, with 72% of severe PICM patients achieving LVEF >35% and most of the improvement occurring within 1 year. These data support initial upgrade to a CRT pacemaker with consideration of further upgrade to CRT defibrillator after 1 year if LVEF remains ≤35%.
本研究旨在确定起搏诱导性心肌病（PICM）患者接受心脏再同步治疗（CRT）升级后改善的程度、时间进程和预测因素。
PICM 是频繁接受右心室（RV）起搏的患者发生心力衰竭的一个重要原因。CRT 可能逆转 PICM。
我们回顾性研究了 2003 年至 2016 年间接受 CRT 治疗的 1279 例连续患者。纳入因 PICM 而从双腔或单腔心室起搏器升级为 CRT 的患者。PICM 的定义为在没有其他心肌病原因的情况下，RV 起搏≥20%的患者中，左心室射血分数（LVEF）降低≥10%，导致 LVEF<50%。严重 PICM 的定义为升级前 LVEF≤35%。确定与严重 PICM 患者 LVEF 恢复程度以及升级后 LVEF>35%相关的临床、心电图和超声心动图特征。
在 69 例 PICM 患者中，LVEF 从中值 7.0 个月时的 29.3%改善至 45.3%。在 54 例严重 PICM 患者中，有 39 例（72.2%）在中值 7.0 个月时 LVEF>35%。大多数改善发生在最初的 3 个月内，但在第一年的剩余时间内仍在继续。在线性回归中，较窄的固有 QRS 与 CRT 升级后 LVEF 的改善程度相关（每降低 10ms，增加 2.00%；p=0.05）。
CRT 对逆转 PICM 非常有效，72%的严重 PICM 患者 LVEF>35%，且大多数改善发生在 1 年内。这些数据支持初始升级为 CRT 起搏器，如果 LVEF 仍≤35%，可考虑在 1 年后进一步升级为 CRT 除颤器。
