Serrano C V, Bortolotto L A, César L A, Solimene M C, Mansur A P, Nicolau J C, Ramires J A
Heart Institute, Coronary Care Unit, São Paulo, SP, Brazil.
Int J Cardiol. 1999 Jan;68(1):75-82. doi: 10.1016/s0167-5273(98)00344-1.
Differentiation of right coronary artery (RCA) from left circumflex artery (LCxA) occlusion may be difficult since both can present an electrocardiographic pattern of inferior myocardial infarction (IMI). We studied 133 patients with IMI, 92 patients with RCA occlusion and 41 patients with LCxA occlusion. Risk factors such as previous MI, arterial hypertension, diabetes, smoking, and dislipemia, were similar for RCA and LCxA occlusions. Patients with RCA occlusion had a higher incidence of isolated IMI than patients with LCxA occlusion, 50% vs. 17%, respectively (P<0.001). Arterial hypotension was more prevalent (P<0.05) among patients with RCA (18%) rather than those with LCxA occlusion (2%). RCA occlusion presented an association with sinus bradycardia, an association not observed with LCxA occlusion (15% vs. 0%, respectively; P<0.01). Total atrioventricular block was only present among patients with RCA (18%). Proximal occlusions of the RCA presented lower heart rates (sinus bradycardia) than medial and distal occlusions (13% vs. 1% and 1%, respectively; P<0.0001 and P<0.001). Therefore, regarding patients with IMI: (1) sinus bradycardia is more frequent when the infarct-related artery is the RCA; (2) proximal occlusions of the right coronary predispose low heart rates; and (3) occlusion of the LCxA rarely induces sinus bradycardia.
由于右冠状动脉（RCA）闭塞和左旋支动脉（LCxA）闭塞都可能呈现下壁心肌梗死（IMI）的心电图模式，因此区分二者可能存在困难。我们研究了133例IMI患者，其中92例为RCA闭塞，41例为LCxA闭塞。RCA闭塞和LCxA闭塞的危险因素，如既往心肌梗死、动脉高血压、糖尿病、吸烟和血脂异常，情况相似。RCA闭塞的患者孤立性IMI的发生率高于LCxA闭塞的患者，分别为50%和17%（P<0.001）。动脉低血压在RCA闭塞患者中更为普遍（P<0.05）（18%），而在LCxA闭塞患者中则较少（2%）。RCA闭塞与窦性心动过缓有关，LCxA闭塞则未观察到这种关联（分别为15%和0%；P<0.01）。完全性房室传导阻滞仅出现在RCA闭塞的患者中（18%）。RCA近端闭塞的患者心率（窦性心动过缓）低于中段和远端闭塞的患者（分别为13%、1%和1%；P<0.0001和P<0.001）。因此，对于IMI患者：（1）当梗死相关动脉为RCA时，窦性心动过缓更为常见；（2）右冠状动脉近端闭塞易导致心率降低；（3）LCxA闭塞很少诱发窦性心动过缓。
