Erbay Ali Riza, Turhan Hasan, Yasar Ayse Saatci, Bicer Asuman, Senen Kubilay, Sasmaz Hatice, Sabah Irfan, Yetkin Ertan
Department of Cardiology, Turkiye Yuksek Ihtisas Hospital, Ankara, Turkey.
Int J Cardiol. 2005 Jun 22;102(1):33-7. doi: 10.1016/j.ijcard.2004.03.079.
P-wave dispersion (PWD), has been defined as the difference between maximum and minimum P-wave duration. Prolonged P-wave duration and increased PWD have been reported to be related with increased risk for atrial fibrillation (AF). AF is the most common sustained arrhythmia encountered in patients with rheumatic mitral stenosis (MS). Beta-blockers are the mainstay of therapy in patients with rheumatic MS to control ventricular rate both during sinus rhythm and AF. In the present study, we aimed to evaluate the effect of long-term beta-blocker therapy on P-wave duration and PWD in patients with rheumatic MS.
Study population includes 46 patients (group I, 8 men, 38 women, mean age = 34+/-8 years) with newly diagnosed moderate-to-severe rheumatic MS who have not taken any medication before and prescribed oral beta-blocker therapy and 46 healthy control subjects without any cardiovascular disease (group II, 8 men, 38 women, mean age = 35+/-7 years). Mitral valve area, maximum and mean diastolic mitral gradients, left atrial diameter, and systolic pulmonary artery pressure were evaluated by transthoracic echocardiography before initiation of beta blocker therapy and repeated at the end of the first month. Baseline maximum and minimum P-wave duration and PWD were determined on 12-lead electrocardiogram recorded for each patient and control subject and repeated at the end of the first month after initiation of beta-blocker therapy in patient group.
Maximum P-wave duration and PWD were found to be significantly higher in patients with MS than those in control subjects (Maximum P-wave duration: 128+/-7 ms vs. 104+/-4 ms and PWD: 52+/-6 ms vs. 27+/-3 ms, p < 0.001 for both). Both groups had comparable minimum P-wave duration (75+/-4 ms vs. 76+/-4 ms, p = 0.093). Maximum P-wave duration and PWD were found to be significantly decreased by long-term beta blocker therapy (Maximum P-wave duration; 128+/-7 ms vs. 122+/-6 ms, p < 0.001, PWD; 52+/-6 ms vs. 47+/-5 ms, p < 0.001). However, there was no significant difference between the values of minimum P wave duration measured before and at the end of the first month of beta-blocker therapy (75+/-4 ms vs. 75+/-3 ms, p = 0.678). Statistically significant decrease were detected on maximum and mean mitral gradient and systolic pulmonary artery pressure and resting heart rate at the end of the first month of beta-blocker therapy. However, only the change in resting heart rate was found to be significantly correlated with the decrease in maximum P-wave duration and PWD (Maximum P-wave duration: r = 0.327, p = 0.026, PWD: r = 0.378, p = 0.01).
We have shown for the first time that long-term beta-blocker therapy causes a significant decrease in maximum P-wave duration and PWD in patients with rheumatic MS.
P波离散度（PWD）被定义为最大与最小P波时限之间的差值。据报道，P波时限延长和PWD增加与心房颤动（AF）风险增加有关。AF是风湿性二尖瓣狭窄（MS）患者中最常见的持续性心律失常。β受体阻滞剂是风湿性MS患者控制窦性心律和AF期间心室率的主要治疗药物。在本研究中，我们旨在评估长期β受体阻滞剂治疗对风湿性MS患者P波时限和PWD的影响。
研究人群包括46例新诊断为中重度风湿性MS且此前未服用任何药物并接受口服β受体阻滞剂治疗的患者（I组，8例男性，38例女性，平均年龄=34±8岁）以及46例无任何心血管疾病的健康对照者（II组，8例男性，38例女性，平均年龄=35±7岁）。在开始β受体阻滞剂治疗前通过经胸超声心动图评估二尖瓣面积、最大和平均舒张期二尖瓣压差、左心房直径以及收缩期肺动脉压，并在第一个月末重复评估。在为每位患者和对照者记录的12导联心电图上确定基线最大和最小P波时限以及PWD，并在患者组开始β受体阻滞剂治疗后的第一个月末重复测量。
发现MS患者的最大P波时限和PWD显著高于对照者（最大P波时限：128±7毫秒对104±4毫秒，PWD：52±6毫秒对27±3毫秒，两者p均<0.001）。两组的最小P波时限相当（75±4毫秒对76±4毫秒，p = 0.093）。发现长期β受体阻滞剂治疗可使最大P波时限和PWD显著降低（最大P波时限：128±7毫秒对122±6毫秒，p < 0.001，PWD：52±6毫秒对47±5毫秒，p < 0.001）。然而，在β受体阻滞剂治疗前和第一个月末测量的最小P波时限值之间无显著差异（75±4毫秒对75±3毫秒，p = 0.678）。在β受体阻滞剂治疗第一个月末，最大和平均二尖瓣压差、收缩期肺动脉压以及静息心率有统计学意义的降低。然而，仅发现静息心率的变化与最大P波时限和PWD的降低显著相关（最大P波时限：r = 0.327，p = 0.026，PWD：r = 0.378，p = 0.01）。
我们首次表明，长期β受体阻滞剂治疗可使风湿性MS患者的最大P波时限和PWD显著降低。
