Murín Pavol, Mitro Peter, Valočik Gabriel, Spurný Peter, Stančák Branislav
Vnitr Lek. 2014 May-Jun;60(5-6):431-6.
Cardiac resynchronization therapy (CRT) improves symptoms and survival in patients with chronic heart failure. The presence of electrocardiographic (ECG) signs of electrical dyssynchrony during ventricular contractions are an essential criterion for the implantation of CRT. Nevertheless, 1/3 proportion of patients who undergo CRT do not seem to respond favorably. Aim of study was to investigate the relevant ECG parameters prior to CRT (as well as their postimplantation changes) and to determine their relation to predicting favorable response to CRT.
52 symptomatic patients (age 62.2 ± 10.5 years, 39 men) with severe left ventricular (LV) systolic dysfunction (ejection fraction 26.3% ± 6.9%) with QRS 120 ms underwent CRT implantation. In early pre- and postimplantation CRT period the following ECG parameters were recorded: QRS complex width and morphology (complete and atypical left bundle branch block, nonspecific intraventricular conduction delay), the size of R and S wave. After 6 months of CRT, responders were definied by improvement of LV ejection fraction > 5 % and/or reduction of end-systolic LV volume > 15 %.
The incidence of left bundle branch block (complete or atypical) prior to CRT implantation was higher in responders compared to non-responders group (64% vs 35%, p = 0.036). After implantation of CRT, responders showed significant narrowing of the QRS complex, while non-responder`s QRS complex width remained unchanged (QRS -18 ± 22 ms vs 1 ± 27 ms, p = 0.018). Furthermore QRS complex reduction led to increase in LV ejection fraction (r = 0.47, p = 0.001) and to reduction of LV end-systolic volume (r = 0.42, p = 0.004). R and S changes between responders and non-responders did not differ (p = 0.598 respectively, P = 0.685).
The presence of complete left bundle branch block before CRT implantation is associated with a better response to CRT compared to other myocardial intraventricular conduction disturbances. Post-implantation narrowing of QRS complex appears to be an early predictor of favorable response to CRT.
心脏再同步治疗（CRT）可改善慢性心力衰竭患者的症状并提高生存率。心室收缩期间存在心电图（ECG）电不同步征象是植入CRT的重要标准。然而，接受CRT治疗的患者中有三分之一似乎反应不佳。本研究的目的是调查CRT治疗前的相关ECG参数（以及植入后的变化），并确定它们与预测CRT良好反应的关系。
52例有症状的患者（年龄62.2±10.5岁，男性39例），患有严重左心室（LV）收缩功能障碍（射血分数26.3%±6.9%），QRS时限≥120 ms，接受了CRT植入。在CRT植入前和植入后的早期，记录以下ECG参数：QRS波群宽度和形态（完全性和非典型性左束支传导阻滞、非特异性室内传导延迟）、R波和S波大小。CRT治疗6个月后，根据左心室射血分数提高>5%和/或左心室收缩末期容积减少>15%来定义反应者。
与无反应者组相比，反应者组CRT植入前完全性或非典型性左束支传导阻滞的发生率更高（64%对35%，p = 0.036）。植入CRT后，反应者的QRS波群明显变窄，而无反应者的QRS波群宽度保持不变（QRS -18±22 ms对1±27 ms，p = 0.018）。此外，QRS波群变窄导致左心室射血分数增加（r = 0.47，p = 0.001）和左心室收缩末期容积减少（r = 0.42，p = 0.004）。反应者和无反应者之间的R波和S波变化无差异（分别为p = 0.598，P = 0.685）。
与其他心肌室内传导障碍相比，CRT植入前存在完全性左束支传导阻滞与对CRT的更好反应相关。植入后QRS波群变窄似乎是对CRT良好反应的早期预测指标。
