Cabrera Bueno Fernando, Rodríguez Bailón Isabel, López Salguero Raúl, Gómez Doblas Juan J, Pérez Cabeza Alejandro, Peña Hernández José, Domínguez Franco Antonio, Morcillo Hidalgo Luis, de Teresa Galván Eduardo
Servicio de Cardiología, Hospital Universitario Virgen de la Victoria, Málaga, Spain.
Rev Esp Cardiol. 2004 Dec;57(12):1179-87.
Dynamic left intraventricular outflow tract obstruction occurs occasionally in patients without hypertrophic cardiomyopathy. We hypothesized that dynamic intraventricular obstruction might occur during effort in patients with angina or dyspnea without evident disease. The objective of this prospective study was to investigate: a) whether it appears with effort; b) its incidence, magnitude and determining factors, and c) its clinical course.
We performed baseline and stress Doppler echocardiography in 211 patients with angina, dyspnea or both with exercise. Patients with previous myocardial infarction, valvular heart disease, ventricular dysfunction or ventricular hypertrophy without hypertension were excluded. Dynamic intraventricular obstruction was defined as intracavitary flow velocity > or =2.5 m/s.
134 patients (59 women) were included: mean age was 58 (9) years; history of hypertension was present in 69.7%, dyslipidemia in 35.8% and diabetes in 24.6%. Dynamic intraventricular obstruction appeared in 18 patients (13.4%), with gradients ranging between 25 and 53 mmHg (mean 32.19 [6.6]). Demographic variables, cardiovascular risk factors and exercise performed were similar in group A (with obstruction) and group B (without obstruction). No patient in group A had evidence of ischemia. Five patients in this group had symptoms during exercise; the gradients were greater in these patients (42.65 [10.5] vs 28.15 [2.37] mmHg; P<.0001) than in the remaining group A patients. Left ventricular outflow tract size was found to be the only independent predictive factor in the multivariate analysis. After 369.9 (133.5) days of follow-up, no cardiac events were recorded.
Our study suggests that some patients with angina or dyspnea without evidence of ischemia may develop dynamic left ventricular outflow tract obstruction induced by effort.
动态性左心室内流出道梗阻偶尔会发生在无肥厚型心肌病的患者中。我们推测，在无明显疾病但有胸痛或呼吸困难的患者用力时可能会发生动态性心室内梗阻。这项前瞻性研究的目的是调查：a）它是否在用力时出现；b）其发生率、严重程度及决定因素；c）其临床病程。
我们对211例有胸痛、呼吸困难或两者兼有的运动患者进行了基础和负荷多普勒超声心动图检查。排除既往有心肌梗死、瓣膜性心脏病、心室功能障碍或无高血压的心室肥厚患者。动态性心室内梗阻定义为心腔内流速≥2.5米/秒。
纳入134例患者（59例女性）：平均年龄58（9）岁；69.7%有高血压病史，35.8%有血脂异常，24.6%有糖尿病。18例患者（13.4%）出现动态性心室内梗阻，压力阶差在25至53毫米汞柱之间（平均32.19 [6.6]）。A组（有梗阻）和B组（无梗阻）的人口统计学变量、心血管危险因素及运动情况相似。A组患者均无缺血证据。该组5例患者在运动时有症状；这些患者的压力阶差（42.65 [10.5] 对比28.15 [2.37] 毫米汞柱；P<0.0001）高于A组其余患者。在多变量分析中，左心室流出道大小是唯一的独立预测因素。随访369.9（133.5）天后，未记录到心脏事件。
我们的研究提示，一些无缺血证据但有胸痛或呼吸困难的患者可能会因用力而发生动态性左心室流出道梗阻。
