Implantable loop recorder in diagnostics of cardiac arrhythmias: the importance of drug treatment in predicting pacemaker requirement

Background Implantable loop recorder (ILR) represents gold standard in diagnosis of cardiac arrhythmias in patients presenting with transitory neurological or cardiac symptoms. The aim of our study was to determine its real-world diagnostic effectiveness detecting arrhythmias requiring pacemaker implantation. Methods This retrospective, observational clinical study enrolled 62 ILR recipients from Cardiology Clinic of the Clinical Center Kragujevac, which were followed-up for 2 years. Demographic and clinical data were obtained from patients’ medical records. Results By the end of the monitoring, some form of cardiac rhythm disorder (most commonly bradyarrhythmias) was observed in 36% of the study population, and in 34% a pacemaker or cardioverter defibrillator was implanted. The most common indication for pacemaker implantation were pauses in cardiac activity (83%), followed by bradycardia (33%); atrioventricular block (11%) and atrial fibrillation (6%). Univariable logistic regression analysis showed that the use of oral anticoagulants (OR [95% CI]: 0.014 [1.77; 154.55]), ACE inhibitors or AT receptor blockers (OR [95% CI]: 0.022 [1.210; 12.352]), and diuretics (OR [95% CI]: 0.008 [1.549; 18.035]) had a statistically significant impact on the diagnostic value of ILR in detecting arrhythmias requiring pacemaker. After adjustment for other factors of influence, only oral anticoagulants (OR [95% CI]: 0.042 [1.091; 1112.8]) and diuretics (OR [95% CI]: 0.043 [1.047; 14.623]) remained significant in predicting pacemaker requirement in ILR recipients. Conclusion Our study shows that ILR represents an effective diagnostic approach in detecting cardiac arrhythmias requiring pacemaker implantation, especially in patients treated with oral anticoagulants or diuretics. The relevance of previous treatment with ACE inhibitors or AT receptor blockers remains to be confirmed in the future