Continuous cardiac monitoring in epilepsy: an implantable loop manual activation algorithm for improving ECG signal acquisition accuracy.

BACKGROUND: The muscle artifacts, caused by prominent muscle contractions, mimicking cardiac arrhythmias, might compromise the ECG signal quality and the implantable loop recorder memory capacity in patients with epilepsy. We developed an epileptic seizures clinical pattern-based implantable loop recorder manual activation algorithm, presenting its real-world efficacy here. METHODS: One hundred ninety-three patients (18-60 years) with drug-resistant focal epilepsy were consecutively enrolled and underwent a subcutaneous loop recorder implantation. Patients with focal onset-aware seizures and patients with focal impaired awareness seizures /bilateral tonic-clonic seizures without aura were recommended to use the activator once - just after the episode. Patients with focal impaired awareness seizures/bilateral tonic-clonic seizures with aura, the caregivers of patients experiencing status epilepticus, were advised to use the activator twice - during the aura and after the episode/ regaining consciousness. RESULTS: Six thousand four hundred ninety-four ECG traces (4826 - auto-triggered events, 1668 - person-activated events) were recorded and analyzed. The rate of true positive events in the person-activated group was statistically higher than in the autoactivation group (72.5% vs.19.4%, p < 0.0001). Person-activated false-positive events were observed in 30.5% of patients with focal impaired awareness seizures and 27.7% in patients with bilateral tonic-clonic seizures. The highest rate of false-positive events (61.5%) was detected in patients undergoing epileptic status, and the lowest rate (3.8%) - was in patients with focal onset aware seizures. The rate of false-positive events was significantly higher in patients with impaired awareness seizures without aura both in focal impaired awareness (45.5% vs. 19.3%, p < 0.0001) and bilateral tonic-clonic seizure groups (38.8% vs. 5.9%, p < 0.0001). CONCLUSIONS: Arrhythmias with varying clinical outcomes are expected in epilepsy patients and have been monitored continuously. The specified loop recorder external activation algorithm can improve the clinically relevant cardiac arrhythmia detection accuracy in epilepsy patients and the value of future studies.

Cardiac arrhythmias and sudden unexpected death in epilepsy: Results of long-term monitoring.

BACKGROUND: Cardiac rhythm and conduction disorders are common in patients with epilepsy and are presumably one of the leading causes of sudden unexpected death. There are only a few published reports on ictal cardiac arrhythmias detected by continuous monitoring, and the majority had a small sample size. OBJECTIVE: The aim of this study was to evaluate the frequency and type of cardiac arrhythmias recorded by an implantable loop recorder in patients with drug-resistant epilepsy. METHODS: We implanted a subcutaneous loop recorder to 193 patients with drug-resistant epilepsy. Automatic triggers to initiate cardiac rhythm recording were cardiac pauses of >3 seconds and any episodes of bradycardia (≤45 beats/min) or tachycardia (≥150 beats/min). Patients/relatives were instructed to begin peri-ictal rhythm recording by using an external activator device. The follow-up duration was 36 months, with scheduled follow-up visits every 3 months. RESULTS: A total of 6494 electrocardiogram traces were recorded during the median follow-up of 36 months (interquartile range 3-36 months). Ictal heart rhythm and rate changes were detected in 143 patients (74%). The most common finding was ictal sinus tachycardia (66.8%). Sinus bradycardia was observed in 13 patients (6.7%). Three patients had clinically relevant cardiac pauses of >6 seconds, requiring permanent pacemaker implantation. Five patients (2.6%) died suddenly. CONCLUSION: Ictal heart rhythm and rate changes occur in most of the patients with drug-resistant epilepsy. Clinically relevant cardiac events, related to ictal and postictal periods, are rare. No potentially malignant arrhythmias were detected in patients who died suddenly during the preceding follow-up period.

Radiofrequency versus Cryoballoon Ablation of Atrial Fibrillation: An Evaluation Using ECG, Holter Monitoring, and Implantable Loop Recorders to Monitor Absolute and Clinical Effectiveness.

INTRODUCTION: While several studies have compared the radiofrequency current (RFC) and cryoablation for the treatment of patients with atrial fibrillation (AF), no study has monitored the long-term outcomes with the usage of implantable loop recorders (ILRs). METHODS: We enrolled 89 consecutive patients with nonvalvular paroxysmal AF (N = 44 for RFC and N = 45 for cryoballoon). The primary efficacy end point was the assessment of effectiveness for each group (RFC versus cryoballoon) when examining freedom from arrhythmia by monitoring with ECG, Holter, and implantable loop recoder (ILR). The primary safety end point compared rates of adverse events between both groups. The secondary efficacy end point examined the duration of the postablation blanking period from ILR retrieved data. RESULTS: The mean age of the study population was 56.6 ± 10.2 years, and the follow-up duration was 12 months. There were no differences in baseline patient characteristics between groups. At 12 months, the absolute effectiveness (measured by ILR) was 65.9% in the RFC group and 51.1% in the cryoballoon group (OR = 1.85; 95% CI: 0.79-4.35; p = 0.157), and the clinical effectiveness (measured by ECG and Holter) was 81.8% in the RFC group and 55.6% in the cryoballoon group (OR = 3.6; 95% CI: 1.37-9.46; p = 0.008). There was no difference in safety between both groups. Asymptomatic episodes were significantly more present in the RFC group as measured by ILRs (p < 0.010). In cryoballoon group, arrhythmia episodes were recorded equally irrespective of the follow-up method (i.e., ECG and Holter versus ILR (p > 0.010)). The blanking period does not seem to be as important in cryoballoon as compared to RFC. CONCLUSION: RFC and cryoballoon ablation had similar absolute effectiveness at 12 months. ECG and Holter were effective when assessing the efficacy of the cryoballoon ablation; however, in the RFC group, ILR was necessary to accurately assess long-term efficacy.