Morillo Carlos A., Baranchuk Adrián
Arrhythmia Service-Cardiology Division, McMaster University, HGH-McMaster Clinic 5th Floor, 237 Barton Street East, Hamilton, Ontario L8L 2X2, Canada.
Curr Treat Options Cardiovasc Med. 2004 Oct;6(5):371-383. doi: 10.1007/s11936-004-0021-8.
Syncope, defined as a transient loss of consciousness and postural tone with spontaneous recovery and no neurologic sequelae, is among one of the most common causes of consultation with a physician. The diagnostic workup is complex but can be simplified if focused on the underlying condition. Prognosis is highly dependent on the presence or absence of structural heart disease, primarily the presence of cardiomyopathy regardless of etiology, particularly if the left ventricular (LV) function is less than 35%. The diagnostic approach to the patient with recurrent syncope and no structural heart disease is targeted to rule out neurally mediated causes. This approach usually includes a tilt table test (ie, head-up tilt), carotid sinus massage in patients older than 55 years, and an adenosine challenge test in patients who remain with unexplained syncope. Unexplained syncope in patients with reduced LV function (< 35%) may be potentially life-threatening. Infrequent causes of syncope should be sought in younger patients with a family history of sudden cardiac death. Channelopathies such as the long QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia are among this variety. Therapy should address the potential mechanism of syncope. In neurally mediated causes, restoration of orthostatic tolerance, primarily by increasing volume during orthostatic stress, is recommended. Physiologic countermaneuvers and increase in salt and water intake are usually the initial therapy. With syncope in patients with an LV dysfunction (< 35%), an ICD is frequently recommended after ruling out common causes of syncope. Syncope in the elderly is usually multifactorial and therapy should include reassessment of multiple medications, which can promote neurally mediated syncope as well as searching for bradycardic causes. Empiric pacing may be used in this complex group of patients.
晕厥定义为伴有自发恢复且无神经后遗症的短暂意识丧失和姿势性肌张力丧失，是患者就诊的最常见原因之一。诊断检查很复杂，但如果专注于潜在病因则可简化。预后高度依赖于是否存在结构性心脏病，主要是心肌病的存在，无论病因如何，特别是如果左心室（LV）功能低于35%。对于复发性晕厥且无结构性心脏病的患者，诊断方法旨在排除神经介导的病因。这种方法通常包括倾斜试验（即头高位倾斜）、对55岁以上患者进行颈动脉窦按摩，以及对仍有不明原因晕厥的患者进行腺苷激发试验。左心室功能降低（<35%）的患者出现不明原因晕厥可能有潜在生命危险。对于有心脏性猝死家族史的年轻患者，应寻找晕厥的罕见病因。长QT综合征、Brugada综合征和儿茶酚胺能多形性室性心动过速等离子通道病属于此类。治疗应针对晕厥的潜在机制。对于神经介导的病因，建议主要通过在直立应激期间增加血容量来恢复直立耐受性。生理对抗动作以及增加盐和水的摄入量通常是初始治疗方法。对于左心室功能障碍（<35%）的患者出现晕厥，在排除晕厥的常见病因后，通常建议植入植入式心脏复律除颤器（ICD）。老年人的晕厥通常是多因素的，治疗应包括重新评估多种药物，这些药物可促进神经介导的晕厥以及寻找心动过缓的病因。对于这一复杂的患者群体可采用经验性起搏治疗。
