A cross sectional study on prevalence and etiology of syncope in Tehran.

Recurrent syncope of obscure etiology, particularly in those with structural heart diseases, is associated with higher mortality rates. There are insufficient and conflicting data on prevalence and etiology of syncope in the urban Middle Eastern population. Evaluating the etiologic basis of syncope can be an effective step in prevention of morbidities and sudden cardiac death in susceptible populations. The aim of our study was to determine the prevalence and etiology of syncope in an outpatient cardiology clinic in Tehran the capital of Iran. In this cross sectional study data was collected from patients' records whose first visits were from March 2006 to September 2007 and had undergone thorough examination for syncope (ECG, Holter monitoring, echocardiography, Tilt table testing, Electrophysiological study). All efforts were done to determine underlying heart diseases, physical exam and test abnormalities, final diagnosis and treatment in all selected patients. Overall prevalence of syncope was estimated to be 9%. The age-specific prevalence rates were 5-14 years:  4.14%, 15-44 years: 44.8%, 45-64 years: 31%, 65 years and Older: 20%. The most frequently identified cause (60%) was neurally-mediated (vasovagal) syncope. Mean age of patients was 44.9 years with a minimum of 5 years and maximum of 85 years. In our study, coronary heart disease had a high prevalence among participants (12.4%). Syncope is a common clinical problem. In this study prevalence rates peaked in 15-44 years age group. Considering that recurrent syncope is often disabling and may cause injury and the fact that heart diseases are more common in people affected by syncope, especial cautions should be taken while evaluating this group of patients.