Transmission and loss of ECG snapshots: Remote monitoring in implantable cardiac monitors

INTRODUCTION: Remote monitoring including transmission of electrocardiogram (ECG) strips has been implemented in implantable cardiac monitors (ICM). We appraise whether the physician can rely on remote monitoring to be informed of all possibly significant arrhythmias. METHODS: We analyzed remote monitoring transmissions of patients in the ongoing BIO|GUARD-MI study, in which Biotronik devices are used. Once per day, the devices automatically transmit messages with up to six ECG snapshots to the Home Monitoring Service Center. If more than one type of arrhythmia is recorded during a day, at least one ECG of each arrhythmia type is transmitted. RESULTS: 212 study patients were registered at the service center. The mean age of the patients was 70 ± 8 years, and 74% were male. Patients were followed for an average of 13 months. The median time from device implantation until the first message receipt in the service center was 2 days. The median patient-individual transmission success was 98.0% (IQR 93.6-99.8) and remained stable in the second and third year. The most frequent arrhythmias were atrial fibrillation, bradycardia and high ventricular rate. 17.3% of the messages with ECG snapshots contained more than one arrhythmia type. DISCUSSION: Our analysis confirms that the physician can rely on Home Monitoring to be informed of all possibly significant arrhythmias during long-term follow-up. We have found hints that the transmission of only one episode per day may lead to the loss of clinically relevant information if patients with ICMs are followed by remote monitoring only.