Marstrand Peter, Almatlouh Kasim, Kanters Jørgen K, Graff Claus, Christensen Alex Hørby, Bundgaard Henning, Theilade Juliane
Department of Cardiology, Herlev-Gentofte Hospital, University Hospital of Copenhagen, Herlev, Denmark; Department of Emergency Medicine, Slagelse Hospital, Denmark.
Department of Cardiology, Herlev-Gentofte Hospital, University Hospital of Copenhagen, Herlev, Denmark.
Heart Rhythm. 2021 Feb;18(2):241-249. doi: 10.1016/j.hrthm.2020.08.017. Epub 2020 Aug 31.
In patients with long QT syndrome (LQTS), swimming and loud noises have been identified as genotype-specific arrhythmic triggers in LQTS type 1 (LQTS1) and LQTS type 2 (LQTS2), respectively.
The purpose of this study was to compare LQTS group responses to arrhythmic triggers.
LQTS1 and LQTS2 patients were included. Before and after beta-blocker intake, electrocardiograms were recorded as participants (1) were exposed to a loud noise of ∼100 dB; and (2) had their face immersed into cold water.
Twenty-three patients (9 LQTS1, 14 LQTS2) participated. In response to noise, LQTS groups showed similarly increased heart rate, but LQTS2 patients had corrected QT interval (Fridericia formula) (QTcF) prolonged significantly more than LQTS1 patients (37 ± 8 ms vs 15 ± 6 ms; P = .02). After intake of beta-blocker, QTcF prolongation in LQTS2 patients was significantly blunted and similar to that of LQTS1 patients (P = .90). In response to simulated diving, LQTS groups experienced a heart rate drop of ∼28 bpm, which shortened QTcF similarly in both groups. After intake of beta-blockers, heart rate dropped to 28 ± 2 bpm in LQTS1 patients and 20 ± 3 bpm in LQTS2, resulting in a slower heart rate in LQTS1 compared with LQTS2 (P = .01). In response, QTcF shortened similarly in LQTS1 and LQTS2 patients (57 ± 9 ms vs 36 ± 7 ms; P = .10).
When exposed to noise, LQTS2 patients had QTc prolonged significantly more than did LQTS1 patients. Importantly, beta-blockers reduced noise-induced QTc prolongation in LQTS2 patients, thus demonstrating the protective effect of beta-blockers. In response to simulated diving, LQTS groups responded similarly, but a slower heart rate was observed in LQTS1 patients during simulated diving after beta-blocker intake.
在长QT综合征（LQTS）患者中，游泳和噪音分别被确定为1型长QT综合征（LQTS1）和2型长QT综合征（LQTS2）特定基因型的心律失常触发因素。
本研究的目的是比较LQTS组对心律失常触发因素的反应。
纳入LQTS1和LQTS2患者。在服用β受体阻滞剂前后，记录参与者在以下情况下的心电图：（1）暴露于约100分贝的噪音中；（2）面部浸入冷水中。
23名患者（9名LQTS1患者，14名LQTS2患者）参与研究。在对噪音的反应中，LQTS组心率同样增加，但LQTS2患者的校正QT间期（弗里德里西亚公式）（QTcF）延长显著多于LQTS1患者（37±8毫秒对15±6毫秒；P = 0.02）。服用β受体阻滞剂后，LQTS2患者的QTcF延长明显减弱，与LQTS1患者相似（P = 0.90）。在对模拟潜水的反应中，LQTS组心率下降约28次/分钟，两组的QTcF缩短情况相似。服用β受体阻滞剂后，LQTS1患者心率降至28±2次/分钟，LQTS2患者降至20±3次/分钟，导致LQTS1患者心率低于LQTS2患者（P = 0.01）。相应地，LQTS1和LQTS2患者的QTcF缩短情况相似（57±9毫秒对36±7毫秒；P = 0.10）。
暴露于噪音时，LQTS2患者的QTc延长显著多于LQTS1患者。重要的是，β受体阻滞剂减少了LQTS2患者噪音诱导的QTc延长。因此证明了β受体阻滞剂的保护作用。在对模拟潜水的反应中，LQTS组反应相似，但服用β受体阻滞剂后，LQTS1患者在模拟潜水期间心率较慢。
