Institute for Cardiovascular Diseases Dedinje, Belgrade, Serbia.
Pacemaker Center, Clinical Center of Serbia, Belgrade, Serbia.
Arch Med Sci. 2014 Aug 29;10(4):684-91. doi: 10.5114/aoms.2014.40790.
In this study, we sought to determine whether myocardial contractile reserve (CR) assessed by dobutamine stress echocardiography (DSE) can identify patients who experience nearly complete normalization of left ventricular (LV) function after the implantation of a cardiac resynchronization therapy (CRT) pacemaker.
The study group consisted of 55 consecutive patients with non-ischemic dilated cardiomyopathy, LV ejection fraction (LVEF) < 35%, and prolonged QRS complex duration, who were scheduled for CRT pacemaker implantation. The DSE (20 µg/kg/min) was performed in all patients. The CR assessment was based on a change in the wall motion score index (ΔWMSI) and ΔLVEF during DSE. Super-response was defined as an increase in LVEF to > 50% and reduction in left ventricular end-systolic dimension to < 40 mm 12 months following the CRT implantation.
A total of 7 patients (12.7%) were identified as super-responders to CRT. When compared to non-super-responders, these patients had significantly higher values of the dobutamine-induced change in ΔWMSI (1.031 ±0.120 vs. 0.49 ±0.371, p < 0.01), and ΔEF (17.9 ±2.2 vs. 8.8 ±6.2, p < 0.01). Receiver operating characteristic analysis showed that dobutamine-induced changes in ΔWMSI ≥ 0.7 and ≥ 14% for ΔEF are the best discriminators for a super-response. Patients with ΔWMSI ≥ 0.7 and ΔEF ≥ 14% are significantly less often hospitalized (p < 0.01) for worsening of heart failure during 28.5 ±3.0 months of the follow-up.
Contractile reserve assessed by DSE can identify patients with dilated cardiomyopathy who are likely to experience near normalization of LV function following CRT.
本研究旨在探讨多巴酚丁胺负荷超声心动图（DSE）评估的心肌收缩储备（CR）是否能识别出接受心脏再同步治疗（CRT）起搏器植入后左心室（LV）功能几乎完全正常化的患者。
研究组纳入了 55 例非缺血性扩张型心肌病、LV 射血分数（LVEF）<35%且 QRS 波群持续时间延长的连续患者，这些患者均计划植入 CRT 起搏器。所有患者均进行 DSE（20μg/kg/min）检查。CR 的评估基于 DSE 期间的室壁运动评分指数（WMSI）变化和ΔLVEF。超反应定义为 LVEF 增加>50%，左心室收缩末期内径减小<40mm，在 CRT 植入后 12 个月。
共有 7 例（12.7%）患者被确定为 CRT 的超反应者。与非超反应者相比，这些患者的多巴酚丁胺诱导的ΔWMSI变化值显著更高（1.031±0.120 比 0.49±0.371，p<0.01）和ΔEF（17.9±2.2 比 8.8±6.2，p<0.01）。受试者工作特征曲线分析显示，多巴酚丁胺诱导的ΔWMSI变化≥0.7 和 ΔEF 变化≥14%是超反应的最佳预测因子。ΔWMSI≥0.7 和 ΔEF≥14%的患者在 28.5±3.0 个月的随访期间因心力衰竭恶化而住院的情况显著减少（p<0.01）。
DSE 评估的收缩储备可识别出接受 CRT 后 LV 功能可能接近正常化的扩张型心肌病患者。
