Nunes Maria Carmo P, Abreu Cláudia Drumond G, Ribeiro Antônio Luiz P, Barbosa Marcia M, Rincon Leonor G, Reis Rodrigo Citton P, Rocha Manoel Otávio C
Department of Internal Medicine, School of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Pacing Clin Electrophysiol. 2011 Feb;34(2):155-62. doi: 10.1111/j.1540-8159.2010.02921.x. Epub 2010 Oct 1.
Asynchronous electrical activation induced by right ventricular (RV) pacing can cause several abnormalities in left ventricular (LV) function. However, the effect of ventricular pacing on RV function has not been well established. We evaluated RV function in patients undergoing long-term RV pacing.
Eighty-five patients and 24 healthy controls were included. After pacemaker implantation, conventional echocardiography and strain imaging were used to analyze RV function. Strain imaging measurements included peak systolic strain and strain rate. LV function and ventricular dyssynchrony by tissue Doppler imaging (TDI) were assessed. Intra- and interobserver variabilities of TDI parameters were tested on 15 randomly selected cases.
All patients were in New York Heart Association functional class I or II and percentage of ventricular pacing was 96 ± 4%. RV apical induced interventricular dyssynchrony in 49 patients (60%). LV dyssynchrony was found in 51 patients (60%), when the parameter examined was the standard deviation of the time to peak myocardial systolic velocity of all 12 segments greater than 34 ms. Likewise, septal-to-lateral delay ≥ 65 ms was found in 31 patients (36%). All echocardiographic indexes of RV function were similar between patients and controls (strain: -22.8 ± 5.8% vs -22.1 ± 5.6%, P = 0.630; strain rate: -1.47 ± 0.91 s(-1) vs -1.42 ± 0.39 s(-1) , P = 0.702). Intra- and interobserver variability for RV strain was 3.1% and 5.3%, and strain rate was 1.3% and 2.1%, respectively.
In patients with standard pacing indications, RV apical pacing did not seem to affect RV systolic function, despite induction of electromechanical dyssynchrony.
右心室（RV）起搏引起的不同步电激活可导致左心室（LV）功能出现多种异常。然而，心室起搏对右心室功能的影响尚未完全明确。我们评估了接受长期右心室起搏患者的右心室功能。
纳入85例患者和24名健康对照者。起搏器植入后，采用常规超声心动图和应变成像分析右心室功能。应变成像测量包括峰值收缩期应变和应变率。通过组织多普勒成像（TDI）评估左心室功能和心室不同步性。在15例随机选择的病例中测试了TDI参数的观察者内和观察者间变异性。
所有患者均为纽约心脏协会心功能I级或II级，心室起搏百分比为96±4%。49例患者（60%）右心室心尖部诱发了心室间不同步。当检查参数为所有12个节段心肌收缩期峰值速度时间的标准差大于34毫秒时，51例患者（60%）发现左心室不同步。同样，31例患者（36%）发现室间隔至侧壁延迟≥65毫秒。患者和对照者之间右心室功能的所有超声心动图指标相似（应变：-22.8±5.8%对-22.1±5.6%，P = 0.630；应变率：-1.47±0.91 s(-1)对-1.42±0.39 s(-1)，P = 0.702）。右心室应变的观察者内和观察者间变异性分别为3.1%和5.3%，应变率分别为1.3%和2.1%。
在有标准起搏指征的患者中，尽管诱发了电机械不同步，但右心室心尖部起搏似乎并未影响右心室收缩功能。
