Risk stratification parameters as assessed by continuous long-term cardiac monitoring in pulmonary hypertension – heart rate variability, heart rate, and physical activity

Abstract

Abstract Background Pulmonary hypertension (PH) is a progressive disease affecting both the pulmonary vasculature and the heart. In the current ESC/ERS guidelines nine variables are used in PH risk assessment, and have been proven to be independent predictors of survival in PH. The risk assessment parameters include clinical symptoms, exercise capacity and imaging. The present study is the first to assess continuous 24/7 heart rate variability (HRV), heart rate (HR) and physical activity monitoring in patients with PH. Purpose To identify risk stratification parameters by continuous cardiac monitoring in PH. Methods Patients diagnosed with PH were included in this prospective single-centre study. Patients had a Reveal LINQ insertable cardiac monitor implanted to continuously monitor heart rate variability (HRV), heart rate at day and night and physical activity. HRV was expressed as the mean HRV in sinus rhythm during each full day (SDANN method). Pearson and Spearman correlations between the loop recorder variables and ESC/ERS risk stratification variables were calculated and compared with the loop recorder data in 30-days intervals. Results A total of 41 patients were prospectively enrolled, 27 patients with pulmonary arterial hypertension (PAH) and 14 patients with chronic thromboembolic pulmonary hypertension (CTPEH). The patients were monitored continuously in a total of 82 patient-years, had a mean age of 58 years and were primarily in a stable disease phase with a mean WHO functional class (FC) of 2.2. HRV and physical activity divided by heart rate at daytime showed the highest correlations respectively with current risk parameters. In particular, high correlations were found between HRV and NT-proBNP (R=−0,69 p≤2.2e-16), WHO FC (R=−0,65 p=2.4e-5), RVEF (R=0,61 p=0,00012) and right atrial pressure (RAP) (R=−0.67 p=0.0023) (Figure 1). Conclusion This study demonstrates the potential of HRV, and physical activity divided by heart rate daytime as risk parameters in pulmonary hypertension. Progression of symptoms in PH are often delayed compared with pathophysiological changes, and continuous monitoring offers a potential to early recognition of disease progression and optimization of PAH therapy. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): The study was supported by the Heart Centre Research Council,Rigshospitalet and an investigator initiated study research grant fromJansson Pharmaceuticals.