[Usefulness of implantable loop recorder in the diagnosis of undetermined syncope. Report of a clinical case].

In this paper we describe the case of a 42-year-old man who presented with rather infrequent episodes of syncope. In view of this symptomatology, he had been repeatedly hospitalized and submitted to a complete diagnostic workup inclusive of brain computed tomography, head-up tilt test, repeated Holter monitoring, and electrophysiologic evaluation. Unfortunately, none of these tests allowed the formulation of a precise diagnosis. When, owing to further episodes of syncope, the patient came to our observation, after an inconclusive new series of noninvasive tests, we decided to implant an insertable loop recorder. This device revealed that a phase of severe bradycardia lasting 53 s, with 15 s of complete asystole, occurred during symptoms thus allowing us to diagnose the cause of syncope.