Department of Internal Medicine, Unity Health System, 1555 Long Pond Road, Rochester, NY 14616, USA.
Cardiol J. 2011;18(4):395-400.
Prolonged corrected QT interval (QTc) holds independent prognostic importance in predicting mortality in patients with coronary artery disease, diabetes mellitus and congestive heart failure. However, its association with all cause or cardiac mortality in the general population remains unclear. We evaluated the relationship between prolonged QTc and total mortality among patients with syncope.
This was a retrospective study of 348 patients presenting to the emergency department with syncope of any etiology over a period of one year. All patients with atrial fibrillation, left bundle branch block and cardiac devices (pacemaker/defibrillator) were excluded. Prolonged QTc interval was defined as QTc interval ≥ 440 ms. The primary end point for this study was total mortality in patients presenting with syncope.
There were 58 (16%) deaths in this population during a mean follow-up of 30 months. Patients with prolonged QTc interval had significantly higher mortality when compared to those with normal QTc interval (22% vs 11%; p = 0.004). This significance was not retained after adjustment for covariates in the Cox regression model, where we found that age ≥ 65 years (hazard ratio [HR] 7.9; 95% confidence interval [CI] 1.9-32.9; p = 0.004) and QTc interval ≥ 500 ms (HR 3.5; 95% CI 1.56-8.12; p = 0.002) were predictors of increased mortality among patients with syncope.
In elderly patients presenting to the emergency department with syncope, QTc interval ≥ 500 ms helps identify patients at higher risk of adverse outcomes.
在患有冠状动脉疾病、糖尿病和充血性心力衰竭的患者中，延长的校正 QT 间期（QTc）对预测死亡率具有独立的预后意义。然而，其与一般人群的全因或心脏死亡率的关系尚不清楚。我们评估了延长 QTc 与晕厥患者全因死亡率之间的关系。
这是一项回顾性研究，纳入了在一年内因任何病因就诊于急诊科的 348 例晕厥患者。所有患有心房颤动、左束支传导阻滞和心脏器械（起搏器/除颤器）的患者均被排除。延长的 QTc 间隔定义为 QTc 间隔≥440ms。本研究的主要终点是晕厥患者的总死亡率。
在平均 30 个月的随访期间，该人群中有 58 例（16%）死亡。与 QTc 正常的患者相比，QTc 延长的患者死亡率显著更高（22%比 11%；p=0.004）。在校正 Cox 回归模型中的协变量后，这种显著性不再保留，我们发现年龄≥65 岁（危险比[HR]7.9；95%置信区间[CI]1.9-32.9；p=0.004）和 QTc 间隔≥500ms（HR 3.5；95% CI 1.56-8.12；p=0.002）是晕厥患者死亡率增加的预测因素。
在因晕厥就诊于急诊科的老年患者中，QTc 间隔≥500ms 有助于识别预后不良风险较高的患者。
