Is There Any Room for Adenosine Test in Syncope of Unknown Origin

Some patients with unexplained syncope develop different degrees of paroxysmal AV block with bolus infusion of 18-mg of adenosine. This finding had a low positive predictive value in recent trials, although its use was not standardized.ObjectiveTo present the experience in our institution in follow up of patients with a first episode of unexplained malignant syncope of uncertain etiology (SUE), to whom were systematically carried out an adenosine test.Material and MethodsThere were included, in a prospective and consecutive way, patients who presented unexplained syncope with severe trauma, none of them had a previous history of syncope, without suspected vasovagal etiology, without organic cardiopathy, with normal neurological and cardiological studies (including sensitized tilt test), to those who underwent an adenosine test. The test was carried out at the end of the electrophysiological study. It was infused in bolus of 18-mg of adenosine through the femoral vein under continuous ECG monitoring; positive test was defined by the development of complete AV block with pauses longer than 6 seconds.Background