Calé Rita, Mendes Miguel, Brito João, Sousa Pedro, Carmo Pedro, Almeida Sofia, Gomes Renata, Ferreira António, Santos Katya Reis, Cavaco Diogo, Morgado Francisco, Adragão Pedro, Calqueiro João, Silva José Aniceto
Serviço de Cardiologia Hospital Santa Cruz, C.H.L.O., Lisboa, Portugal.
Rev Port Cardiol. 2011 Feb;30(2):199-212.
Patients with dilated cardiomyopathy and implantable cardioverter-defibrillator (ICD) are a high-risk group for arrhythmias. They regularly undergo cardiopulmonary exercise testing (CPET) to assess cardiac reserve and to guide clinical decisions or therapeutic adjustments. Data from previous studies demonstrate that prognosis in patients with heart failure (HF) worsens with the presence of appropriate shocks.
The purpose of this study was to evaluate the value of CPET parameters to predict shocks and other arrhythmic events in HF patients with ICD, in order to identify a high-risk group for arrhythmias.
This was a prospective single-center registry of 61 consecutive patients (mean age 55 +/- 15 years, 18% female), with dilated cardiomyopathy (ischemic etiology in 57%) and ICD, who underwent symptom-limited maximal CPET six months or less before device implantation. Minimum follow-up was 180 days. The primary endpoint was appropriate shock and the composite endpoint was appropriate shock and/or ventricular fibrillation (VF) and/or sustained ventricular tachycardia (VT), which were then correlated with hemodynamic variables (heart rate and blood pressure) and CPET parameters.
During a mean follow-up of 27 months, eight patients died (13%), two of them from arrhythmic cause (3.3%), and 16 (26%) patients received at least one appropriate ICD shock, eight (13%) due to VF. Sustained VT was recorded in 23 patients (38%) and nonsustained VT in 42 patients (69%). CPET showed that the group with the primary end point had lower peak VO2, anaerobic threshold and chronotropic reserve. On multivariate analysis, resting heart rate was the only independent predictor of appropriate shock (HR 1.06; 95% CI 1.01-1.10; p = 0.025). Univariate analysis identified peak VO2, anaerobic threshold, VE/VCO2 slope, resting heart rate and heart rate decrease during the first minute of recovery, and systolic blood pressure during exercise as predictive of the composite endpoint (shock/VF/sustained VT). Multivariate analysis identified resting heart rate and peak VO2 as independent predictors, with HR 1.04; 95% CI 1.00-1.09 (p = 0.050) and HR 0.88; 95% CI 0.78-0.98 (p = 0.026), respectively. The best cut-off for resting heart rate to predict the composite and primary endpoints was > 76 bpm (area under the ROC curve: 0.67; 95% CI 0.53-0.78 and 0.65; 95% CI 0.51-0.76, respectively).
Resting heart rate and peak VO2 were identified in multivariate analysis as good predictors of arrhythmic events and resting heart rate was the only independent predictor of appropriate shock in HF patients with ICD. Both advanced stage heart failure and sympathetic overdrive may be associated with the development of malignant arrhythmias.
扩张型心肌病且植入了植入式心脏复律除颤器（ICD）的患者是心律失常的高危人群。他们定期接受心肺运动试验（CPET）以评估心脏储备，并指导临床决策或治疗调整。既往研究数据表明，心力衰竭（HF）患者若出现恰当电击，其预后会恶化。
本研究旨在评估CPET参数对预测植入ICD的HF患者发生电击及其他心律失常事件的价值，以便识别心律失常的高危人群。
这是一项前瞻性单中心注册研究，纳入了61例连续患者（平均年龄55±15岁，18%为女性），患有扩张型心肌病（57%为缺血性病因）且植入了ICD，在装置植入前6个月或更短时间内接受了症状限制性最大CPET。最短随访时间为180天。主要终点是恰当电击，复合终点是恰当电击和/或心室颤动（VF）和/或持续性室性心动过速（VT），然后将其与血流动力学变量（心率和血压）及CPET参数相关联。
在平均27个月的随访期间，8例患者死亡（13%），其中2例死于心律失常原因（3.3%），16例（26%）患者至少接受了一次恰当的ICD电击，8例（13%）因VF接受电击。23例患者（38%）记录到持续性VT，42例患者（69%）记录到非持续性VT。CPET显示，有主要终点的组峰值VO2、无氧阈值和变时性储备较低。多因素分析显示，静息心率是恰当电击的唯一独立预测因素（HR 1.06；95%CI 1.01 - 1.10；p = 0.025）。单因素分析确定峰值VO2、无氧阈值、VE/VCO2斜率、静息心率、恢复第1分钟内心率下降以及运动时收缩压可预测复合终点（电击/VF/持续性VT）。多因素分析确定静息心率和峰值VO2为独立预测因素，HR分别为1.04；95%CI 1.00 - 1.09（p = 0.050）和HR 0.88；95%CI 0.78 - 0.98（p = 0.026）。预测复合终点和主要终点的静息心率最佳截断值>76次/分钟（ROC曲线下面积：分别为0.67；95%CI 0.53 - 0.78和0.65；95%CI 0.51 - 0.76）。
多因素分析确定静息心率和峰值VO2是心律失常事件的良好预测因素，静息心率是植入ICD的HF患者恰当电击的唯一独立预测因素。晚期心力衰竭和交感神经过度激活都可能与恶性心律失常的发生有关。
