Heart Rate Variability in Pulmonary Arterial Hypertension.

Abstract

Resting heart rate has been incorporated in REVEAL risk assessment. Rest and sleep heart rate variability (HRV) measured in the home setting could provide early insight into worsening physiology in patients with pulmonary arterial hypertension (PAH). We hypothesized continuous HRV monitoring in the home setting for 7 days would be a treatment responsive measure and be associated with outcomes in PAH. This was a prospective observational study completed at the University of Rochester. We recruited two groups, one with stable background therapy and another with therapy intensification during the study. MC10 Biostamp (continuous electrocardiogram heart rate monitoring) was worn for 7 days at baseline and follow up; stable patients completed monitoring twice within 4 weeks while treatment intensification patients were assessed 3 months later. HRV was calculated using MC10 proprietary algorithm. Baseline, follow up, and changes in heart rate and HRV (rest and sleep) were compared between the groups and correlated to clinical outcomes at 2 years. Periods of activity were excluded from analysis. Non-parametric testing was performed. Twenty-four (10 stable and 14 treatment intensification) PAH patients had paired monitoring sessions during sleep and rest. There were no statistical differences in heart rate or HRV values at baseline or follow-up within either stable PAH patients or those requiring treatment escalation. Additionally, the change in heart rate from baseline to follow-up did not differ significantly between the two groups. There was no difference in HRV between patients who had clinical worsening (parenteral therapy, hospitalization, or death) within 2 years, while elevated rest and sleep heart rate did predict clinical worsening at 2 years. Unlike left ventricular systolic failure, continuous HRV for 7 days in the home setting does not appear to improve assessment in PAH, and functional testing appears to be a better way to assess treatment response and risk for clinical worsening.