Charisopoulou Dafni, Koulaouzidis George, Law Lucy F, Rydberg Annika, Henein Michael Y
Institute of Public Health and Clinical Medicine, Umea University, 90187 Umea, Sweden.
Division of Pediatric Cardiology, Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands.
J Clin Med. 2020 Dec 24;10(1):37. doi: 10.3390/jcm10010037.
Electromechanical heterogeneities due to marked dispersion of ventricular repolarisation and mechanical function have been associated with symptoms in long QT syndrome (LQTS) patients; Aim: To examine the exercise response of longitudinal LV systolic and diastolic myocardial function and synchronicity in LQTS patients and its relationship with symptoms; Methods: Forty seven (age 45 ± 15 yrs, 25 female, 20 symptomatic) LQTS patients and 35 healthy individuals underwent an exercise test (Bruce protocol). ECG and echo parameters were recorded at rest, peak exercise (p.e.), and recovery; Results: LQTS patients had prolonged and markedly dispersed myocardial contraction, delayed early relaxation phase, and significantly decreased filling time at all exercise phases. Unlike controls, these electromechanical disturbances deteriorated further with exercise, during which additional decrease of the LV diastolic myocardial function and attenuated LV stroke volume were noted. Such abnormal responses to exercise were seen to a greater degree in symptomatic patients and in the LQT1 subgroup and improved with B-blocker therapy. Worsening myocardial contraction dispersion at p.e. was the strongest discriminator for previous clinical events, and its discriminating power excelled further by adding early relaxation delay; Conclusions: Electromechanical disturbances were shown to worsen during exercise in LQTS patients and were more pronounced in those with previous arrhythmic events.
由于心室复极和机械功能的显著离散导致的机电异质性与长QT综合征（LQTS）患者的症状有关；目的：研究LQTS患者左心室纵向收缩和舒张心肌功能及同步性的运动反应及其与症状的关系；方法：47例（年龄45±15岁，女性25例，有症状者20例）LQTS患者和35名健康个体进行运动试验（Bruce方案）。在静息、运动高峰（p.e.）和恢复时记录心电图和超声心动图参数；结果：LQTS患者心肌收缩延长且显著离散，早期舒张期延迟，在所有运动阶段充盈时间显著缩短。与对照组不同，这些机电紊乱在运动时进一步恶化，在此期间左心室舒张心肌功能进一步下降，左心室搏出量减弱。这种对运动的异常反应在有症状的患者和LQT1亚组中更为明显，并随着β受体阻滞剂治疗而改善。运动高峰时心肌收缩离散度恶化是既往临床事件的最强鉴别指标，通过增加早期舒张延迟其鉴别能力进一步提高；结论：结果显示，LQTS患者运动时机电紊乱会恶化，且在既往有心律失常事件的患者中更为明显。
