Division of Cardiology, Department of Internal Medicine, School of Medicine, Dankook University, 119, Dandae-ro, Dongnam-gu, Cheonan-si, Chungnam 31116, Republic of Korea.
J Electrocardiol. 2021 May-Jun;66:54-61. doi: 10.1016/j.jelectrocard.2021.02.012. Epub 2021 Mar 3.
Right ventricular (RV) apical pacing is associated with systolic dysfunction and heart failure. Paced QRS duration has been suggested as a predictor of heart failure and left ventricular (LV) systolic dysfunction. However, the effect of paced QRS duration on LV diastolic function is not well known.
This study was designed to evaluate the relationship between paced QRS duration and LV diastolic function.
This retrospective study included 88 patients who had chronic RV apical pacing. Myocardial relaxation was assessed with tissue Doppler imaging. Patients with severe valvular dysfunction or significant structural heart disease were excluded. Paced QRS duration was measured with standard 12‑lead ECG at follow-up.
Median age of the patients was 65.9 years (interquartile ranges (IQR), 56.5, 72.7) with 64.8% of female patients. Median duration of RV pacing was 8.6 years (IQR, 5.3, 11.1). Major indication of RV pacing was complete atrioventricular block (89.8%), and dual chamber pacemakers were predominantly implanted (89.8%). Mean of paced QRS duration was 160.5 ± 18.2 msec. Median LV ejection fraction (EF) was 63% (IQR, 55.5, 67.5), and negatively correlated with paced QRS duration (R = -0.478, p < 0.001). LV end diastolic dimension was positively correlated with paced QRS duration (R = 0.531, p < 0.001). Mean E' velocity at the septal mitral annulus was 5.2 ± 1.5 and negatively related to paced QRS duration (R = -0.521, p < 0.001). After adjusting covariables, paced QRS duration was independently related to E' velocity (beta = -0.038, p = 0.005). Paced QRS duration was also associated with worsening functional capacity or elevated LV filling pressure in patients with preserved EF (odd ratio = 1.10; 95% confidence interval, 1.02-1.20, p = 0.015).
Paced QRS duration was associated with LV relaxation which might be another possible mechanism of worsening heart failure in patients with long paced QRS duration.
右心室（RV）心尖部起搏与收缩功能障碍和心力衰竭有关。起搏后的 QRS 时限已被认为是心力衰竭和左心室（LV）收缩功能障碍的预测指标。然而，起搏后 QRS 时限对 LV 舒张功能的影响尚不清楚。
本研究旨在评估起搏后 QRS 时限与 LV 舒张功能之间的关系。
本回顾性研究纳入了 88 例慢性 RV 心尖部起搏患者。采用组织多普勒成像评估心肌弛豫。排除严重瓣膜功能障碍或有明显结构性心脏病的患者。在随访时，用标准 12 导联心电图测量起搏后的 QRS 时限。
患者的中位年龄为 65.9 岁（四分位间距（IQR），56.5，72.7），女性占 64.8%。RV 起搏的中位时间为 8.6 年（IQR，5.3，11.1）。RV 起搏的主要适应证为完全性房室传导阻滞（89.8%），主要植入双腔起搏器（89.8%）。起搏后的 QRS 时限平均为 160.5±18.2msec。中位左心室射血分数（EF）为 63%（IQR，55.5，67.5），与起搏后的 QRS 时限呈负相关（R=-0.478，p<0.001）。LV 舒张末期内径与起搏后的 QRS 时限呈正相关（R=0.531，p<0.001）。间隔二尖瓣环的平均 E'速度为 5.2±1.5，与起搏后的 QRS 时限呈负相关（R=-0.521，p<0.001）。在校正了协变量后，起搏后的 QRS 时限与 E'速度独立相关（β=-0.038，p=0.005）。起搏后的 QRS 时限也与 EF 保留的患者心功能恶化或 LV 充盈压升高有关（比值比=1.10；95%置信区间，1.02-1.20，p=0.015）。
起搏后的 QRS 时限与 LV 舒张有关，这可能是起搏后 QRS 时限较长的患者心力衰竭恶化的另一个可能机制。
