Maendely R, Aldakar M, d'Hautefeuille B, Fontaine G, Linares-Cruz E, Frank R, Tonet J L, Grosgogeat Y
Service de Rythmologie et de Stimulation cardiaque, Hôpital Jean-Rostand, Ivry.
Ann Cardiol Angeiol (Paris). 1987 Jul-Sep;36(7):355-9.
Myocardial infarction is sometimes accompanied by bradycardia requiring either temporary or permanent cardiac pacing. In addition an MI reduces the amplitude of endocardial action potentials which produces the conditions for defective detection of spontaneous ventricular complexes by the pacemaker. In this particular condition, the competing cardiac rhythm which arises frequently causes malignant arrhythmias which are potentially fatal. This danger is increased even further by endocardial stimulation of the right ventricle with myocardial infarction of the right ventricle. We have reported in this paper the instructive case of a patient with coronary heart disease, hospitalized for third degree AV block with syncope which developed following a massive postero-diaphragmatic MI, but with few symptoms. After secondary extension of the necrotic area, the artificial pacemaker implanted manifested defective firing which resulted in development of ventricular fibrillation. The latter was controlled by cardioversion, but the patient died from disordered conduction after 30 seconds of complete asystole. For one minute, the pacemaker did not stimulate the ventricle because of "electrical stunt to the myocardium", caused by the shock from the defibrillator. Anatomical examination (at autopsy) confirmed the cardiac rupture.
心肌梗死有时会伴有心动过缓，需要临时或永久心脏起搏。此外，心肌梗死会降低心内膜动作电位的幅度，这为起搏器对自发性心室复合波的检测出现缺陷创造了条件。在这种特殊情况下，频繁出现的竞争性心律会引发潜在致命的恶性心律失常。右心室心肌梗死时对右心室进行心内膜刺激会进一步增加这种危险。我们在本文中报告了一例冠心病患者的典型病例，该患者因后膈面大面积心肌梗死后出现三度房室传导阻滞并伴有晕厥而住院，但症状较少。坏死区域继发扩展后，植入的人工起搏器出现起搏故障，导致室颤发生。室颤通过心脏复律得到控制，但患者在完全心脏停搏30秒后死于传导紊乱。由于除颤器电击造成的“心肌电休克”，起搏器有一分钟未刺激心室。解剖检查（尸检）证实了心脏破裂。
