Abstract 17233: Implantable Loop Recorder Monitoring Detects a High Incidence of Bradycardia Leading to Pacemaker Implant in Hemodialysis Patients: Preliminary Results From the Monitoring in Dialysis (MiD) Study

Abstract

Introduction: Hemodialysis (HD) pts have an increased incidence of syncope and sudden death. A greater understanding of the incidence of bradyarrhythmias as a potential risk factor for these events is needed. The MiD study enrolled maintenance HD pts to undergo implantable loop recorder (ILR) placement to determine the arrhythmia incidence in this population. Hypothesis: ILR monitoring will be useful in detecting bradyarrhythmias and guiding treatment in ESRD patients Methods: MiD is a prospective, multi-center study to characterize arrhythmias in HD pts during 12mo of ILR monitoring. All ILR-detected events with stored ECG are visually reviewed for confirmation during the initial 6mo. Clinically significant arrhythmias include bradycardia <=40bpm for 6sec, asystole >=3sec, or sustained VT >=130bpm for >=30sec. Results: Follow up is available for 45 pts [mean follow-up 6.4mo (0.6-12.0mo), mean age 56 (27-76yrs), 36% female]. Bradycardia events occurred in 16/45 pts (36%) with an incidence of 28.7 (95% CI 10.1-81.7) events per patient month in these 16 pts. Bradycardia was confirmed by visual review in 408 out of 456 ILR-detected brady events with stored ECG occurring during the first 6mo for a positive predictive value (PPV) of 89.5%. An additional 27 of these ILR-detected “brady events” were found to contain either premature ventricular contractions or atrial arrhythmias (PPV for any arrhythmia 95.5%). 4 of 45 subjects (8.9%) have undergone permanent pacemaker implant for bradyarrhythmias or symptomatic tachy-brady syndrome. In comparison, only one patient (2.2%) has been observed to have ventricular tachycardia (VT>=130bpm for >=30seconds). There was no association between timing of dialysis and bradyarrhythmias. Conclusions: ILR monitoring detects bradyarrhythmias with high PPV in > 1/3 of HD pts and is associated with a high incidence (9%) of permanent pacemaker implant. With improvement in ILR technology with respect to size and wireless capability, clinicians should have a low tolerance to evaluate HD patients for bradyarrhythmias. These findings may also have implications when considering ESRD patients at increased risk of sudden cardiac death for subcutaneous-only defibrillators that do not currently have permanent pacing capability.