The Usefulness of Heart Rate Variability Spectral Analysis in Detecting Covert Atrial Fibrillation among Patients with Cryptogenic Stroke

Abstract

We examined the usefulness of heart rate variability spectral analysis as a predictor of covert paroxysmal atrial fibrillation (PAF), an essential risk factor for embolic stroke. Between July 2021 and January 2022, 77 patients (mean age, 76.3 ± 10.9 years) hospitalized with cryptogenic stroke within 3 days of symptom onset were monitored by telemetry electrocardiogram (ECG) transmitter Duranta^®. Autonomic nervous activity up to maximum 30 days after monitoring by Duranta^® was analyzed and PAF was detected in 8 patients. During 24-hour post-monitoring, 8 patients with PAF had significantly higher levels of low-frequency components (LF), high-frequency components (HF), and HF normalization units and significantly lower levels of LF/HF ratio than those without PAF. Conversely, the results showed the trend of LF/HF ratio to increase and the HF values to decrease preceding the onset of PAF. These findings suggest that parasympathetic activity is predominant in the acute phase of ischemic stroke patients with PAF, but sympathetic activity become predominant towards the PAF occurrence.