Implantable monitor may aid diagnosis of syncope. (Data from Large Randomized Trial).

BERLIN -- The implantable loop recorder is the best technology to date for the diagnosis of recurrent syncope, Dr. Neil Sulke said at the 24th Congress of the European Society of Cardiology.

He presented the largest prospective randomized trial to date comparing the use of such a device with conventional diagnostic testing and management in patients with syncope.

The Medtronic Inc.-sponsored trial, which utilized the company's Reveal Plus implantable loop recorder (ILR), was called the Eastbourne Syncope Assessment Study (EaSyAS). It involved 198 consecutive patients who presented to Eastbourne (England) District General Hospital with a history of two or more unexplained syncopal episodes during the last year and no indication for pacing after carotid sinus massage and head-up tilt-table testing.

During a mean follow-up of 276 days, the cause of syncope was diagnosed in 34% of patients who were randomized to the ILR and in 4% of those in the conventionally managed group.

The primary study end point--the time to an ECG diagnosis of syncope as involving bradycardia, ventricular tachycardia, supraventricular tachycardia, or sinus rhythm--was ninefold shorter in the ILR group than in the conventional group. The time to introduction of ECG-guided therapy was eightfold briefer in the ILR group, said Dr. Sulke of Eastbourne.

He characterized the ILR as "the portable cardiologist that's with the patient at all times." The Reveal Plus device is half the size of a pack of gum. It has no leads. It is placed under the skin above the heart during a 10-minute outpatient procedure done under local anesthesia. The device constantly monitors the heart, automatically recording an ECG if it senses that the heart rate is slowing or accelerating, or if the patient activates it when feeling ...