[Diagnosis and follow-up of 330 patients admitted for syncope in the Department of Cardiology and Neurology. How important is an interdisciplinary study?].

Many mechanisms of different nature-hemodynamic, metabolic and reflex-may cause syncope. We have studied all patients referred for syncope to the Divisions of Cardiology and Neurology of our Hospital, focusing five end-points: standardize a diagnostic protocol; evaluate the diagnostic value of the different tools in the diagnosis of syncope; evaluate the causes of syncope in our patients; value the importance of systematic cardiological-neurological co-operation in these patients; observe the prognosis of patients with syncopal attacks. We have studied 330 patients referred to our Divisions for syncopal attacks (239 in Cardiology and 91 in Neurology) with a protocol organized in 4 steps of increasing levels of complexity: step 1: history, clinical examination, standard electrocardiogram, carotid sinus massage, chest radiography, neurological and cardiological examination; step 2: two-dimensional Doppler echocardiography, dynamic 24-72 hour ECG, standard electroencephalogram (EEG), head-up tilt-table test; step 3: EEG after sleep deprivation, computed tomography, Doppler evaluation of carotid flows, transesophageal electrophysiologic study (EPS); step 4: Oxford test for 24-hour evaluation of arterial blood pressure, intracavitary EPS. We have found in 165 patients (50%) a cardiac syncope, in 78 (23.6%) a reflex syncope, in 43 patients (13%) a syncope of different origin ("non cardiac-non reflex") and in 44 patients (13.4%) we have not been able to find a cause of patient's syncopal attacks. We have established a diagnosis in 148 patients (51.7% of diagnoses) with step 1 examinations, in 98 cases (34.2%) with step 2, in 33 (11.5%) with step 3 and in 7 (2.5%) with step 4 examinations. One hundred-twenty three patients - or relatives of died patients-(37.3%) have answered our follow-up questionnaire (mean follow-up 54.85 +/- 13.73 months, range 36-78 months). Among them, patients with cardiac syncope have had a mortality rate of 18.57%, those with reflex syncope of 7.69%, those with "non cardiac-non reflex" syncope of 7.14%. No patients with syncope of unknown origin died. Our study demonstrates that in the evaluation of patients with syncope, the simplest diagnostic tools are of great value: in fact we have obtained 86% of the diagnoses with the first 2 steps examinations. Furthermore, our study confirms that cardiac syncope has a higher mortality rate compared to other forms of syncope. Co-operation between our Divisions has not been very useful in increasing the number of diagnosed cases, but it has allowed to correctly and rapidly direct our attention toward one form of syncope so that we have been able to speed up the diagnostic process.