Division of Cardiology, Department of Medicine, Queen Mary Hospital.
J Cardiovasc Electrophysiol. 2009 Nov;20(11):1237-43. doi: 10.1111/j.1540-8167.2009.01547.x. Epub 2009 Jul 13.
Atrial electromechanical dysfunction might contribute to the development of atrial fibrillation (AF) in patients with sinus node disease (SND). The aim of this study was to investigate the prevalence and impact of atrial mechanical dyssynchrony on atrial function in SND patients with or without paroxysmal AF.
We performed echocardiographic examination with tissue Doppler imaging in 30 SND patients with (n = 11) or without (n = 19) paroxysmal AF who received dual-chamber pacemakers. Tissue Doppler indexes included atrial contraction velocities (Va) and timing events (Ta) were measured at midleft atrial (LA) and right atrial (RA) wall. Intraatrial synchronicity was defined by the standard deviation and maximum time delay of Ta among 6 segments of LA (septal/lateral/inferior/anterior/posterior/anterospetal). Interatrial synchronicity was defined by time delay between Ta from RA and LA free wall.
There were no differences in age, P-wave duration, left ventricular ejection fraction, LA volume, and ejection fraction between with or without AF. Patients with paroxysmal AF had lower mitral inflow A velocity (70 +/- 19 vs 91 +/- 17 cm/s, P = 0.005), LA active empting fraction (24 +/- 14 vs 36 +/- 13%, P = 0.027), mean Va of LA (2.6 +/- 0.9 vs 3.4 +/- 0.9 cm/s, P = 0.028), and greater interatrial synchronicity (33 +/- 25 vs 12 +/- 19 ms, P = 0.022) than those without AF. Furthermore, a lower mitral inflow A velocity (Odd ratio [OR]= 1.12, 95% Confidence interval [CI] 1.01-1.24, P = 0.025) and prolonged interatrial dyssynchrony (OR = 1.08, 95% CI 1.01-1.16, P = 0.020) were independent predictors for the presence of AF in SND patients.
SND patients with paroxysmal AF had reduced regional and global active LA mechanical contraction and increased interatrial dyssychrony as compared with those without AF. These findings suggest that abnormal atrial electromechanical properties are associated with AF in SND patients.
心房机电功能障碍可能导致窦性心动过缓（SND）患者发生心房颤动（AF）。本研究旨在探讨伴有或不伴有阵发性 AF 的 SND 患者心房机械不同步对心房功能的影响。
我们对 30 例接受双腔起搏器治疗的 SND 患者（11 例伴阵发性 AF，19 例不伴阵发性 AF）进行了超声心动图检查，包括组织多普勒成像。组织多普勒指数包括左心房（LA）中部和右心房（RA）壁的心房收缩速度（Va）和时相事件（Ta）。通过 6 个 LA 节段（间隔/侧壁/下壁/前壁/后壁/前间隔）Ta 的标准差和最大时间延迟定义房间内同步性。通过 RA 和 LA 游离壁之间 Ta 的时间延迟定义房间间同步性。
在年龄、P 波持续时间、左心室射血分数、LA 容积和射血分数方面，伴有和不伴有 AF 的患者之间没有差异。阵发性 AF 患者的二尖瓣血流 A 速度较低（70 ± 19 比 91 ± 17 cm/s，P = 0.005），LA 主动排空分数较低（24 ± 14 比 36 ± 13%，P = 0.027），LA 的平均 Va 较低（2.6 ± 0.9 比 3.4 ± 0.9 cm/s，P = 0.028），房间间同步性较大（33 ± 25 比 12 ± 19 ms，P = 0.022）。此外，较低的二尖瓣血流 A 速度（比值比[OR] = 1.12，95%置信区间[CI] 1.01-1.24，P = 0.025）和延长的房间间不同步（OR = 1.08，95% CI 1.01-1.16，P = 0.020）是 SND 患者发生 AF 的独立预测因子。
与不伴 AF 的患者相比，伴阵发性 AF 的 SND 患者的左心房机械收缩的区域性和整体活性降低，房间间不同步增加。这些发现表明，异常的心房机电特性与 SND 患者的 AF 有关。
