da Silva Menezes Antonio
Electrophysiology and Cardiac Stimulation Department, Hospital São Francisco de Assis, Goiânia, Brazil.
J Interv Card Electrophysiol. 2004 Dec;11(3):193-8. doi: 10.1023/B:JICE.0000048569.71590.c5.
Several studies have shown that heart failure may benefit from cardiac resynchronization therapy (CRT). Studies have demonstrated a beneficial effect of right ventricular (RV) bifocal pacing, using two leads at different positions, in similar patient populations. The aim was to evaluate this approach in Chagas disease patients who developed both severe dilated cardiomiopathy and chronic atrial fibrillation.
The study included 30 patients with a mean age of 52 +/- 6 years (16 male), who had atrioventricular block at functional class II or IV (NYHA). Patients underwent endocardial dual-chamber pacemaker implantation with two RV leads-one placed near the RV outflow tract and the other in the apex. Patients were examined by echocardiography, 24-hour Holter, and New York Heart Association (NYHA) class determination before and 3, 6, 12, 18, 24, and 36 months after CRT.
Compared to the baseline, the left ventricular ejection fraction increased in the first month of CRT, the left ventricular end diastolic diameter decreased, all patients were downgraded to NYHA class I or II, and the incidence of ventricular arrhythmias decreased. However, these could not be maintained and worsened after 6 months CRT. There was a mortality rate of 43.3% during the first year, and only 23.3% of patients remained alive after 3 years. They underwent an electrophysiological study, which revealed complex arrhythmias justifying implantable cardioverter defibrillator (ICD) in six out of seven patients.
The favorable effects of RV bifocal pacing could not be maintained beyond the first 6 months, likely due to the ventricular arrhythmias. Therefore, CRT combined with ICD from the outset may be recommended for this patient group.
多项研究表明，心力衰竭患者可能从心脏再同步治疗（CRT）中获益。研究已证实在相似患者群体中，使用位于不同位置的两根导线进行右心室（RV）双焦点起搏具有有益效果。本研究旨在评估这种方法在患有严重扩张型心肌病和慢性心房颤动的恰加斯病患者中的疗效。
本研究纳入30例平均年龄为52±6岁的患者（16例男性），这些患者的心功能分级为II级或IV级（纽约心脏协会[NYHA]）且存在房室传导阻滞。患者接受了心内膜双腔起搏器植入术，两根右心室导线分别置于右心室流出道附近和心尖部。在CRT治疗前以及治疗后3、6、12、18、24和36个月，通过超声心动图、24小时动态心电图监测以及纽约心脏协会（NYHA）分级测定对患者进行检查。
与基线相比，CRT治疗第1个月时左心室射血分数增加，左心室舒张末期直径减小，所有患者的心功能分级降至I级或II级，室性心律失常的发生率降低。然而，这些改善在CRT治疗6个月后未能维持且有所恶化。第一年的死亡率为43.3%，3年后仅有23.3%的患者存活。他们接受了电生理检查，结果显示7例患者中有6例存在复杂心律失常，表明需要植入植入式心律转复除颤器（ICD）。
右心室双焦点起搏的有益效果在6个月后无法维持，可能是由于室性心律失常所致。因此，对于该患者群体，可能建议从一开始就将CRT与ICD联合使用。
