Continuous Monitoring of Heart Rate Variability and Clinical Outcomes in Patients with Implantable Cardioverter Defibrillators

While heart rate variability (HRV) is an established marker of cardiovascular health, the extent to which continuously measured HRV changes over time and the relationship between these changes and clinical outcomes are less clear. We performed a health system analysis of 225 patients implanted with a cardiac defibrillator or cardiac resynchronization device (CRT) with continuous HRV recording capabilities. We found that continuously measured HRV changed modestly over 2 years. Low baseline HRV, which is associated with low parasympathetic tone and/or increases in sym-pathetic tone, pertains a worse clinical prognosis as reflected by a significant association with all-cause hos-pitalization. Observed changes in HRV over 6-months of follow-up were not associated with subsequent out-comes. (Curr Probl Cardiol 2022;48:101520.)

Automated summary

Continuous monitoring of heart rate variability (HRV) in 225 patients with cardiac defibrillators or cardiac resynchronization devices showed modest changes over a 2-year period. Low baseline HRV, indicative of low parasympathetic tone and/or increased sympathetic tone, was associated with worse clinical outcomes in terms of all-cause hospitalization. However, changes in HRV observed over a 6-month follow-up period did not predict subsequent outcomes.