Prospective evaluation of diagnostic work-up in syncope patients: results of the PL-US registry

Abstract

Syncope is a common problem. Demographic and clinical characteristics of patients admitted to different types of centres may vary, physician's adherence to the guidelines has been examined only in a few studies, and the requirements for implantable loop recorders (ILR) have not been well defined. The aim of this study was to (i) compare demographic and clinical characteristics of patients with syncope diagnosed and treated in tertiary electrophysiology cardiac centres and those attending syncope units or general hospitals, (ii) assess how physicians adhere to the published guidelines, and (iii) calculate the requirement for ILR insertion. In total, 669 consecutive patients with syncope, admitted to 18 electrophysiological cardiac tertiary centres over a mean of 3 months (range 1-10 months), entered a special Internet database called the PL-US (Polish patients with Unexplained Syncope) registry. Detailed demographic and clinical characteristics of the patients, including the results of all diagnostic tests performed, were analysed. Adherence to the guidelines was assessed, based on the published recommendations. The ILR implantation was indicated when (i) all other tests were inconclusive (unexplained syncope) and (ii) syncope associated with injury or presence of organic heart disease or past medical history and ECG suggesting arrhythmic syncope. Syncope of cardiac/arrhythmic origin was the most frequent diagnosis (53%), followed by reflex syncope (33%). Adherence to the guidelines was less than satisfactory-measurement of blood pressure in an upright position, carotid sinus massage, exercise testing, and electrophysiological study were underused, whereas prolonged ECG monitoring and neurological consultations were overused. Unexplained syncope had 58 (9%) patients, and 42 (72%) of them had indication for ILR which accounts for 6% of the whole study population. The calculated need for ILR was 222 implants/million inhabitants/year. Patients with syncope admitted to the tertiary electrophysiology cardiac centres are a highly selected group of patients with syncope and differ in their characteristics as well as underlying diseases to those managed at general hospitals, outpatient clinics, or special syncope units. In Poland, the adherence to the published guidelines is far from satisfactory. At least 6% of all consecutive patients with syncope are candidates for ILR insertion.