Fakhri S; Boston University Medical Center, Boston, Massachusetts, USA.
Campedelli L; Risbano MG

European Journal of Clinical Investigation. 55(2):e14343, 2025 Feb.

BACKGROUND: Preload insufficiency is an underrecognized cause of exercise
intolerance identified during invasive cardiopulmonary exercise testing,
and defined hemodynamically by decreased biatrial filling pressures,
cardiac output, and oxygen consumption (VO2) at peak effort. Patients with
preload insufficiency, however, typically present with symptoms of dyspnea
on exertion, and/or exercise intolerance at submaximal efforts,
particularly when performing activities of daily living. The
cardiopulmonary hemodynamics and physiology at submaximal work levels of
preload insufficiency have not been previously investigated. We
hypothesized that preload insufficiency hemodynamics exist along a
continuum, with submaximal exercise values reflecting peak exercise
cardiopulmonary hemodynamics.
METHODS: We compared submaximal cardiopulmonary hemodynamics, measured at
anaerobic threshold, between preload insufficiency patients and
age-matched controls referred for dyspnea but with normal exercise
responses.
RESULTS: Our study included 66 patients: 41 with preload insufficiency
and 25 controls. Preload insufficiency patients exhibit significantly
reduced VO2, watts, and METS at submaximal levels compared to controls,
alongside earlier anaerobic threshold achievement and similar heart rates
at anaerobic threshold.
CONCLUSIONS: These findings underscore the profound impact of preload
insufficiency on submaximal exercise capacity, emphasizing the importance
of its recognition and management. This insight sets the stage for further
investigations into interventions targeting preload insufficiency at
submaximal exercise levels to enhance both exercise performance and
quality of life.