Linking Severity, Prognosis of Chronic Thromboembolic PH With HRR1 Post Exercise

Asturias, Spain, young woman training in gym on a treadmill, legs section
Is there a link between the severity and prognosis of chronic thromboembolic pulmonary hypertension and attenuated heart rate recovery at 1 minute?

In patients with chronic thromboembolic pulmonary hypertension (CTEPH), attenuated heart rate recovery at 1 minute (HRR1) after exercise has been shown to be a marker of disease severity and is independently associated with prognosis. This was among the results of an investigation into the correlations between HRR1 and functional status, hemodynamics, echocardiography, and prognosis in CTEPH, recently published in the journal Respiration.

The retrospective study was conducted in Fuwai Hospital, Chinese Academy of Medical Sciences, in Beijing, China. Patients who had undergone right heart catheterization (RHC) and cardiopulmonary exercise testing (CPET) between 2014 and 2020 were retrospectively enrolled in the study. The time interval between CPET and RHC needed to be less than 3 months. The primary study outcome was clinical worsening, defined as occurrence of adverse events that included death, rehospitalization due to heart failure or progression of PH, lung transplant, or escalation of PAH therapy. Time to clinical worsening was defined as the time interval between the date of CPET to the end of follow-up or other outcome.

A total of 211 patients with CTEPH who had undergone right heart catheterization and cardiopulmonary exercise testing during the specified time were included in the study. Overall, 43.6% of the participants were female; the median follow-up period was 13.9±8.7 months. During the follow-up, 6 of the patients died, and 39 participants were hospitalized for heart failure, progression of pulmonary hypertension (PH), or escalation of pulmonary arterial hypertension therapy.

Although demographic characteristics did not differ between the group that experienced clinical worsening (CW group; n=45) and the group that did not experience any clinical worsening (non-CW group; n=166), those in the CW group had significantly worse World Health Organization functional class III/IV than did those in the non-CW group (51.1% vs 27.1%, respectively; P =.002). Those in the CW arm were also less likely to receive aggressive treatment (pulmonary endarterectomy: 6.7% vs 22.3%, respectively; balloon pulmonary angioplasty: 31.1% vs 47.0%, respectively; medicine [ie, PH-specific therapy]: 51.1% vs 26.0%, respectively; P <.003).

Following adjustment for confounders, HRR1 had a significant correlation with participants’ functional status, hemodynamics, and echocardiography. In particular, HRR1 was positively associated with 6-minute walk distance (P =.007), mixed venous oxygen saturation (P <.001), and oxygen consumption at peak exercise (P <.001). In contrast, HRR1 was negatively associated with N-terminal-pro brain natriuretic peptide, pulmonary vascular resistance, and ventilatory equivalent of carbon dioxide (P <.001 for all).

Patients with an HRR1 of less than16 beats had an approximately 3-fold risk of experiencing clinical worsening compared with those with an HRR1 of 16 beats or more, with this risk increasing over time.

The researchers concluded that in patients with CTEPH, autonomic nerve dysfunction is highly prevalent, which can be easily recognized by reduced HRR1. Findings from this study demonstrated that HRR1 was linked to established markers of CTEPH severity, with patients with the disorder exhibiting a poorer prognosis and the risk for clinical worsening with time, the investigators added.


Jin Q, Li X, Zhao Z, et al. Heart rate recovery at 1 min after exercise is a marker of disease severity and prognosis in chronic thromboembolic pulmonary hypertensionRespiration. Published online December 2, 2021. doi:10.1159/000520314