Aalborg University, Department of Health Science and Technology, CardioTech, Denmark.
Aalborg University Hospital, Department of Cardiology, Denmark.
Physiol Meas. 2022 Oct 26;43(10). doi: 10.1088/1361-6579/ac94b2.
Conduction-induced heart failure in patients with left bundle branch block (LBBB) can benefit from cardiac resynchronization therapy (CRT). However, some patients are non-responders to the therapy with one contributing factor being poor optimization of the atrioventricular (AV) pacing delay. In this study, we have investigated the pacing-induced changes in the seismocardiogram (SCG).14 patients with heart failure, LBBB, and CRT were included. SCG was recorded with pacing turned on and off. Based on a mean SCG heartbeat from each patient, fiducial points were annotated, and cardiac timing intervals (CTI) and amplitudes were derived. These were compared between the CRT group and a group of healthy normal subjects (= 14). Echocardiography was also used to derive CTI. Intervals derived from the SCG and echocardiogram were correlated.The isovolumetric contraction time (IVCT) derived from SCG was significantly shorter in the CRT group when the pacemaker was turned on (63.2-52.6 ms,= 0.027). The first peak-to-peak amplitude in the systolic complex was significantly larger with the pacemaker turned on (= 0.002), as well as the ∣max-min∣ amplitude in the systolic complex (= 0.003). Isovolumetric relaxation time and left ventricular ejection time (LVET) were not significantly different between pacemaker settings. Compared to normal subjects, IVCT was significantly prolonged with the pacemaker turned off. All amplitudes were significantly larger in the healthy subject group. IVCT and LVET derived from SCG were significantly correlated to the echocardiogram.IVCT shortened and SCG amplitudes increased in response to CRT, indicating a more efficient ventricular contraction. This demonstrates the possibility to detect cardio-mechanic changes in response to treatment with the SCG. However, for the patients the systolic part of the SCG was abnormal and difficult to characterize, raising concerns about the correct interpretation of the SCG.
左束支传导阻滞（LBBB）患者的传导性心力衰竭可受益于心脏再同步治疗（CRT）。然而，一些患者对治疗没有反应，一个原因是房室（AV）起搏延迟优化不佳。在这项研究中，我们研究了起搏引起的地震心动图（SCG）变化。纳入了 14 名心力衰竭、LBBB 和 CRT 的患者。在开启和关闭起搏的情况下记录 SCG。基于每位患者的平均 SCG 心跳，标注基准点，并得出心脏计时间隔（CTI）和幅度。将这些与 CRT 组和一组健康正常受试者（= 14）进行比较。还使用超声心动图得出 CTI。从 SCG 和超声心动图得出的间隔相关。当起搏器开启时，从 SCG 得出的等容收缩时间（IVCT）在 CRT 组中明显缩短（63.2-52.6 ms，= 0.027）。当起搏器开启时，收缩期复合中的第一个峰峰值幅度明显更大（= 0.002），以及收缩期复合中的∣max-min∣幅度（= 0.003）也明显更大。起搏器设置之间的等容舒张时间和左心室射血时间（LVET）没有明显差异。与正常受试者相比，当起搏器关闭时，IVCT 明显延长。健康受试者组的所有幅度均明显更大。从 SCG 得出的 IVCT 和 LVET 与超声心动图显著相关。IVCT 缩短，SCG 幅度增加，表明心室收缩更有效。这表明有可能通过 SCG 检测对治疗的心脏机械变化。然而，对于患者来说，SCG 的收缩期部分异常且难以描述，这引起了对 SCG 正确解释的关注。
