National Heart and Lung Institute, Imperial College London, London, UK.
Department of Internal Medicine and Cardiology, University Hospital Brno, Brno, Czech Republic.
Heart. 2024 Jan 10;110(3):178-187. doi: 10.1136/heartjnl-2023-322878.
To test the hypothesis that in recipients of primary prophylactic implantable cardioverter-defibrillators (ICDs), the non-planarity of ECG vector loops predicts (a) deaths despite ICD protection and (b) appropriate ICD shocks.
Digital pre-implant ECGs were collected in 1948 ICD recipients: 21.4% females, median age 65 years, 61.5% ischaemic heart disease (IHD). QRS and T wave three-dimensional loops were constructed using singular value decomposition that allowed to measure the vector loop planarity. The non-planarity, that is, the twist of the three-dimensional loops out of a single plane, was related to all-cause mortality (n=294; 15.3% females; 68.7% IHD) and appropriate ICD shocks (n=162; 10.5% females; 87.7% IHD) during 5-year follow-up after device implantation. Using multivariable Cox regression, the predictive power of QRS and T wave non-planarity was compared with that of age, heart rate, left ventricular ejection fraction, QRS duration, spatial QRS-T angle, QTc interval and T-peak to T-end interval.
QRS non-planarity was significantly (p<0.001) associated with follow-up deaths despite ICD protection with HR of 1.339 (95% CI 1.165 to 1.540) but was only univariably associated with appropriate ICD shocks. Non-planarity of the T wave loop was the only ECG-derived index significantly (p<0.001) associated with appropriate ICD shocks with multivariable Cox regression HR of 1.364 (1.180 to 1.576) but was not associated with follow-up mortality.
The analysed data suggest that QRS and T wave non-planarity might offer distinction between patients who are at greater risk of death despite ICD protection and those who are likely to use the defibrillator protection.
验证假设，即对于接受原发性预防性植入式心脏复律除颤器（ICD）的患者，心电图向量环的非平面性可预测（a）尽管 ICD 保护仍发生的死亡和（b）恰当的 ICD 电击。
共纳入 1948 例 ICD 接受者的术前数字心电图：21.4%为女性，中位年龄 65 岁，61.5%为缺血性心脏病（IHD）。采用奇异值分解构建 QRS 和 T 波三维环，以测量向量环的平面性。非平面性，即三维环绕单一平面的扭转，与全因死亡率（n=294；15.3%为女性；68.7%为 IHD）和装置植入后 5 年随访期间的恰当 ICD 电击（n=162；10.5%为女性；87.7%为 IHD）相关。采用多变量 Cox 回归比较 QRS 和 T 波非平面性与年龄、心率、左心室射血分数、QRS 持续时间、空间 QRS-T 角、QTc 间期和 T 波峰至 T 波末间期的预测能力。
QRS 非平面性与尽管 ICD 保护仍发生的随访死亡显著相关（p<0.001），HR 为 1.339（95%CI 1.165 至 1.540），但仅与恰当的 ICD 电击单变量相关。T 波环的非平面性是唯一与恰当的 ICD 电击显著相关的心电图衍生指标（p<0.001），多变量 Cox 回归 HR 为 1.364（1.180 至 1.576），但与随访死亡率无关。
分析数据表明，QRS 和 T 波非平面性可能有助于区分尽管 ICD 保护仍发生死亡风险较高的患者和可能使用除颤器保护的患者。
