Almeida Bárbara Carolina Silva, Carmo André Assis Lopes do, Barbosa Marco Paulo Tomaz, Silva José Luiz Padilha da, Ribeiro Antonio Luiz Pinho
Hospital das Clínicas e Faculdade de Medicina da Universidade Federal de Minas Gerais, Belo Horizonte, MG - Brasil.
Departamento de Estatística, Universidade Federal do Paraná, Curitiba, PR - Brasil.
Arq Bras Cardiol. 2018 May;110(5):412-417. doi: 10.5935/abc.20180056. Epub 2018 Apr 9.
Sudden cardiac death is the most frequent death mechanism in Chagas disease, responsible for 55% to 65% of the deaths of patients with chronic Chagas cardiomyopathy (CCC). The most often involved electrophysiological mechanisms are ventricular tachycardia and ventricular fibrillation. The implantable cardioverter defibrillator (ICD) has a beneficial role in preventing sudden death due to malignant ventricular arrhythmias, and, thus the correct identification of patients at risk is required. The association of microvolt T-wave alternans (MTWA) with the appearance of ventricular arrhythmias has been assessed in different heart diseases. The role of MTWA is mostly unknown in patients with CCC.
To evaluate the association between MTWA and the occurrence of malignant ventricular arrhythmias in patients with CCC.
This is a case-control study including patients with CCC and ICD, with history of malignant ventricular arrhythmias (case group), and patients with CCC and no history of those arrhythmias (control group). The MTWA test results were classified as negative and non-negative (positive and indeterminate). The significance level adopted was a = 0.05.
We recruited 96 patients, 45 cases (46.8%) and 51 controls (53.1%). The MTWA test was non-negative in 36/45 cases (80%) and 15/51 controls (29.4%) [OR = 9.60 (95%CI: 3.41 - 27.93)]. After adjustment for known confounding factors in a logistic regression model, the non-negative result continued to be associated with malignant ventricular arrhythmias [OR = 5.17 (95%CI: 1.05 - 25.51)].
Patients with CCC and history of malignant ventricular arrhythmias more often have a non-negative MTWA test as compared to patients with no history of arrhythmia.
心脏性猝死是恰加斯病最常见的死亡机制，占慢性恰加斯心肌病（CCC）患者死亡的55%至65%。最常涉及的电生理机制是室性心动过速和心室颤动。植入式心脏复律除颤器（ICD）在预防恶性室性心律失常导致的猝死方面具有有益作用，因此需要正确识别有风险的患者。微伏级T波电交替（MTWA）与室性心律失常出现的关联已在不同心脏病中进行了评估。MTWA在CCC患者中的作用大多未知。
评估CCC患者中MTWA与恶性室性心律失常发生之间的关联。
这是一项病例对照研究，包括患有CCC且植入ICD、有恶性室性心律失常病史的患者（病例组），以及患有CCC但无心律失常病史的患者（对照组）。MTWA测试结果分为阴性和非阴性（阳性和不确定）。采用的显著性水平为α = 0.05。
我们招募了96名患者，45例（46.8%）为病例组，51例（53.1%）为对照组。MTWA测试在45例中的36例（80%）为非阴性，在51例对照组中的15例（29.4%）为非阴性[比值比（OR）= 9.60（95%置信区间：3.41 - 27.93）]。在逻辑回归模型中对已知混杂因素进行调整后，非阴性结果继续与恶性室性心律失常相关[OR = 5.17（95%置信区间：1.05 - 25.51）]。
与无心律失常病史的患者相比，有恶性室性心律失常病史的CCC患者MTWA测试为非阴性的情况更为常见。
