[Implantable loop recorders in evaluation of syncope].

BACKGROUND

An implantable loop recorder (ILR) registers a one-channel ECG, and stores up to 16 arrhythmic episodes for a maximum of 14 months. It is used to evaluate undiagnosed recurrent arrhythmias, particularly in unexplained syncopes.

MATERIAL AND METHODS

We identified all patients at Ullevål University Hospital who had been investigated with an implantable loop recorder before May 2006. Information on indications for implantation, ECG findings and treatment was found in patient journals and a pacemaker register, and some information was given by the patients themselves. 41 patients were identified.

RESULTS

40 patients had syncope. Symptoms could be explained by information obtained by the ILR in 28/41 (68%) patients. 21/41 (51%) had arrhythmias that correlated with their symptoms; 11 had tachycardia and 10 had bradycardia. They all received specific treatment (13 got a permanent pacemaker, two an ICD, four were prescribed drugs and two had catheter ablation) based on the ILR findings. 7/41 (17%) had normal sinus rhythms during syncope, and an arrhythmic cause of their syncope was excluded. The remaining 13 patients had no syncope during observation. The outcomes were excellent.

INTERPRETATION

The study confirms that ILRs are useful in patients with recurrent syncopes that remain unexplained after conventional work-up.