Background:The optimum cut-off value of premature atrial contraction (PAC) burden (CV-PACb) in 24-h Holter electrocardiography (24-h ECG) for predicting atrial fibrillation (AF) is debatable, with few validation data.

Methods and Results:We retrospectively analyzed 61 patients already diagnosed with AF (AD-AF) and 147 patients never diagnosed with AF (ND-AF), aged ≥50 years, free of heart disease, and who had undergone 24-h ECG and transthoracic echocardiography (TTE). Receiver operating characteristic analysis demonstrated that 0.4% was the optimal CV-PACb differentiating AD-AF from ND-AF, with 69% sensitivity and 72% specificity (area under the curve [AUC] 0.72; 95% confidence interval [CI] 0.65–0.79); however, the left atrial volume index was not significant (AUC 0.60; 95% CI 0.51–0.68). To verify the CV-PACb, new propensity-matched cohorts (i.e., subjects with a PAC burden ≥0.4% and <0.4%; n=69 in each group) were compared based on new detection of AF at a median follow-up of 50 months (interquartile range 12–60 months) Multivariable Cox regression analysis revealed that among 24-h ECG and TTE findings, only PAC burden ≥0.4% was independently associated with incident AF (hazard ratio 5.28; 95% CI 1.28–26.11; P=0.023).

Conclusions:A high PAC burden (≥0.4%) in 24-h ECG was a reliable indicator to identify undiagnosed AF, whereas TTE parameters did not show any predictive value.

背景：在 24 小时动态心电图（24 小时心电图）中预测房颤（AF）的房性早搏（PAC）负荷（CV-PACb）的最佳截止值是有争议的，但验证数据很少。

方法和结果：我们回顾性分析了 61 名已诊断为 AF (AD-AF) 和 147 名从未诊断为 AF (ND-AF)、年龄≥50 岁、无心脏病、接受过 24 小时心电图和经胸超声心动图 (TTE) 的患者）。接受者操作特征分析表明，0.4% 是区分 AD-AF 和 ND-AF 的最佳 CV-PACb，灵敏度为 69%，特异性为 72%（曲线下面积 [AUC] 0.72；95% 置信区间 [CI] 0.65– 0.79); 然而，左心房容积指数不显着（AUC 0.60；95% CI 0.51-0.68）。为了验证 CV-PACb，新的倾向匹配队列（即 PAC 负担≥0.4% 和 <0.4% 的受试者；

结论： 24 小时心电图中的高 PAC 负荷 (≥0.4%) 是识别未确诊 AF 的可靠指标，而 TTE 参数没有显示任何预测价值。