Syncope and electrocardiogram

Introduction Suspected transient loss of consciousness (T-LOC) and syncope are common causes of hospitalization in older patients. Arrhythmias are the most common cardiac causes of syncope. Although a number of instrumental diagnostic procedures are usually routinely performed in patients with suspected syncope, a 12 leads electrocardiogram (ECG) is the only instrumental test recommended for the initial evaluation of these patients. Evidence acquisition In this paper current literature on this topic will be reviewed, including ECG diagnostic criteria and findings suggestive of cardiac syncope. Evidence synthesis The ECG may disclose an arrhythmia associated with a high likelihood of syncope, avoiding further evaluations and permitting institution of specific treatment in 7% of patients referred to emergency department. When the cause of syncope remains uncertain after initial evaluation the next step is to assess the risk of major cardiovascular events or sudden cardiac death. An abnormal ECG selected patients with high probabiliry of cardiac syncope. ECG diagnostic criteria and ECG findings suggesting arrhythmic syncope are presented. Indications and potential clinical implications of ECG monitoring will be discussed too. Conclusions A careful, well-conducted medical history focused on the suspected syncopal event is crucial for the diagnosis. In this setting, the ECG is a mandatory diagnostic tool which, although normal in the majority of patients of syncope, has the potential to identify patients with high likelihood of cardiac syncope due to arrhythmic or cardiopulmonary disorder.