Implantable loop recorder in unexplained palpitations or syncope: A randomised study among young patients with structurally normal heart.

Background: The utility of an implantable loop recorder (ILR) in the evaluation of unexplained syncope or palpitations in young patients in the absence of structural heart disease or ventricular dysfunction is limited. To compare the diagnostic yield of ILR with conventional extended Holter evaluation in the detection of arrhythmias among young patients with a structurally normal heart presenting with unexplained palpitations or syncope.

Methods: Open-label randomised control trial was conducted in a tertiary cardiac care centre among young patients with recurrent unexplained palpitations (≥3 episodes/year) or syncope (≥2 episodes) with normal electrocardiogram and echocardiography, after excluding non-cardiac causes. Patients were block randomised to either ILR implantation or conventional extended Holter monitoring.

Results: Fourteen patients in the ILR group and 16 patients in the conventional group completed the study. The mean age of the patients was 31.9 ± 5.5 and 31.2 ± 5.4 years. Males constituted 78.5% and 75% in the two groups, respectively. Diagnosis was established in 10 (71.5%) patients in the ILR group as compared to only 3 (18.7%) in the conventional group (p = 0.01), with an RR of 0.26 (95% CI 0.089-0.76, p = 0.01). The arrhythmias diagnosed with ILR were narrow complex tachycardia (30%), atrial fibrillation (20%), VPCs (20%), severe bradycardia with asystole due to sinus arrest (10%), VPCs with bigeminy (10%), and ventricular tachycardia (10%).

Conclusion: In young patients with unexplained syncope or palpitations, ILR has a higher diagnostic yield in the accurate detection of arrhythmia compared with conventional Holter strategy, resulting in better management.