Impaired RA reservoir and conduit functions are hallmarks of CTEPH, with compensatory active contraction counteracting the reduction in passive filling, and RAVmaxI and TAPSEra% are valuable noninvasive indices for identifying patients with WHO-FC ≥ III and quantifying CTEPH severity.
CTEPH patients had significantly enlarged right atrial volumes compared to healthy controls.
CTEPH patients demonstrated significantly reduced RA reservoir and conduit (passive emptying) function compared to healthy controls.
CTEPH patients exhibited compensatory increases in active RA contraction relative to total emptying volume.
The atrial component of tricuspid annular plane systolic excursion (TAPSEra%) was significantly higher in CTEPH patients than in controls.
RAVmaxI effectively predicted WHO functional class ≥ III in CTEPH patients.
TAPSEra% effectively predicted WHO functional class ≥ III in CTEPH patients.
The study focused exclusively on CTEPH patients, addressing a gap in the literature where prior RA function studies included heterogeneous pulmonary hypertension etiologies.
This research suggests that in patients with chronic thromboembolic pulmonary hypertension (CTEPH) — a serious condition where blood clots obstruct the pulmonary arteries and raise blood pressure in the lungs — the right upper chamber of the heart (right atrium) undergoes significant functional changes. Specifically, the right atrium becomes enlarged and loses its normal ability to store and passively transfer blood to the lower chamber. To compensate, the atrium works harder through active muscular contraction, which temporarily maintains some pumping function but represents an abnormal adaptive state. The study also found that two measurements obtainable from standard, noninvasive echocardiography (ultrasound of the heart) could reliably identify CTEPH patients with more severe disease. The maximal right atrial volume index (RAVmaxI) and a measure of how much the atrium contributes to a key motion of the tricuspid valve (TAPSEra%) were both strongly associated with worse functional class, shorter walking distances, and higher levels of a blood biomarker of heart stress (NT-proBNP). Both measures showed strong ability to identify patients classified as WHO functional class III or higher — indicating significant limitations in physical activity. This research suggests that routinely measuring these right atrial parameters during standard echocardiographic evaluations of CTEPH patients could provide clinically useful information about disease severity without requiring additional invasive testing. The authors propose that RAVmaxI and TAPSEra% should be integrated into standard echocardiographic protocols for CTEPH assessment, potentially helping clinicians better characterize the degree of heart involvement and track disease progression.
Sun Z, Zhao X, Pan-Han, Li J, Zhang M, Zhu L, et al.. (2026). Assessment of Right Atrial Function in Patients With Chronic Thromboembolic Pulmonary Hypertension.. Echocardiography (Mount Kisco, N.Y.). https://doi.org/10.1111/echo.70444