Continuous heart monitoring to evaluate treatment effects in pulmonary hypertension

Background The treatment of pulmonary hypertension (PH) has improved rapidly in recent decades. There is increasing evidence to support the role of early intervention and treatment in affecting clinical outcomes in PH. Objectives To assess treatment effects before and after the escalation of specific PH treatments using continuous heart monitoring with a Reveal LINQ loop recorder. Methods Patients were compared before and after treatment escalation. Treatment escalation was defined as an additional pulmonary arterial hypertension (PAH) drug, pulmonary endarterectomy, percutaneous balloon angioplasty or bilateral lung transplantation. Specifically, changes in heart rate variability (HRV), heart rate (HR) and physical activity were assessed. Results In this prospective study, 41 patients (27 with PAH and 14 with chronic thromboembolic pulmonary hypertension (CTEPH)) were enrolled. Among them, 15 (36.6%) patients underwent PH treatment escalation. Prior to escalation, patients were monitored for a median of 100 (range: 68–100) days and after therapy escalation for a median duration of 165 (range: 89–308) days. In the escalation group, there was a significant increase in HRV, physical activity indexed by daytime HR and a significant decrease in nighttime HR assessed at baseline and after treatment escalation in both the PAH and CTEPH groups. This was paralleled by significant improvements in WHO functional class, 6-min walking distance and N-terminal pro-b-type natriuretic peptide. Conclusions This is the first study to demonstrate an association between specific PH therapies and changes in HRV, HR nighttime and physical activity. This indicates the potential of continuous monitoring in the evaluation of treatment effects in PH. Data are available upon reasonable request.