Predictors of future arrhythmic events in patients with unexplained syncope.

AIMS

The purpose of this study was to examine the usefulness of implantable loop recorders (ILRs) for symptom-rhythm correlation and to identify predictors of future arrhythmic events.

PATIENTS AND METHODS

In our dual-centre study, we analysed ILR data of 189 patients (mean age 67.4 ± 15.2 years, 114 male) with unexplained syncope (single syncope 21 patients, recurrent 168 patients, traumatic injury 43 patients). Patients had severe comorbidities such as hypertension (n = 127), coronary artery disease (n = 31), diabetes mellitus (n = 33) and chronic renal insufficiency (n = 18). The median ILR usage was 29 months (M), with a range between 1 and 46 M.

RESULTS

Forty-nine (26%) patients experienced syncope during the study, with a median of 8 M to first recurrence of syncope. In 43 patients, pacemaker implantation was performed because of sinus node disease (n = 29), high-degree AV-block (n = 6) or atrial fibrillation with slow ventricular rate (n = 8). In five patients, an ICD was implanted because of documented ventricular tachycardia (n = 4) or left ventricular ejection fraction <35% (n = 1). One patient received ablation of the cavotricuspid isthmus because of documented atrial flutter. Concerning the clinical course, in five patients explantation of the ILR was necessary due to pocket infection. Three patients died due to non-cardiac causes. Logistic regression analysis revealed that older patients had a significantly higher risk for future arrhythmic events (OR 1.3, p = .039).

CONCLUSIONS

ILR monitoring is effective in indicating causes of unexplained syncope by providing symptom-rhythm associations. Only age was a predictor of future arrhythmic events. The mortality in patients with unexplained syncope was very low.