Endurance-trained subjects and sedentary controls increase ventricular contractility and efficiency during exercise: Feasibility of hemodynamics assessed by non-invasive pressure-volume loops

• Published in: PloS one Vol. 18; no. 5; p. e0285592
• Main Authors: Östenson, Björn, Ostenfeld, Ellen, Edlund, Jonathan, Heiberg, Einar, Arheden, Håkan, Steding-Ehrenborg, Katarina
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 10.05.2023; Public Library of Science (PLoS)
• Subjects: Analysis; Arteries - physiology; Basic Medicine; Biology and Life Sciences; Blood pressure; Cardiac function; Coronary artery disease; Coupling; Efficiency; Energy; Exercise intensity; Feasibility Studies; Fysiologi; Fysiologi och anatomi; Health aspects; Heart; Heart beat; Heart diseases; Heart rate; Heart Ventricles - diagnostic imaging; Hemodynamics; Humans; Image acquisition; Magnetic resonance; Magnetic resonance imaging; Measurement; Medical and Health Sciences; Medicin och hälsovetenskap; Medicine and Health Sciences; Medicinska och farmaceutiska grundvetenskaper; Muscle contraction; Physical fitness; Physical Sciences; Physical training; Physiology; Physiology and Anatomy; Research and Analysis Methods; Sedentary behavior; Social Sciences; Software; Stroke Volume - physiology; Ventricle; Ventricular Function, Left - physiology; Sweden; Netherlands
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0285592

Pressure-volume (PV) loops can be used to assess both load-dependent and load-independent measures of cardiac hemodynamics. However, analysis of PV loops during exercise is challenging as it requires invasive measures. Using a novel method, it has been shown that left ventricular (LV) PV loops at rest can be obtained non-invasively from cardiac magnetic resonance imaging (CMR) and brachial pressures. Therefore, the aim of this study was to assess if LV PV loops can be obtained non-invasively from CMR during exercise to assess cardiac hemodynamics. Thirteen endurance trained (ET; median 48 years [IQR 34-60]) and ten age and sex matched sedentary controls (SC; 43 years [27-57]) were included. CMR images were acquired at rest and during moderate intensity supine exercise defined as 60% of expected maximal heart rate. Brachial pressures were obtained in conjunction with image acquisition. Contractility measured as maximal ventricular elastance (Emax) increased in both groups during exercise (ET: 1.0 mmHg/ml [0.9-1.1] to 1.1 mmHg/ml [0.9-1.2], p<0.01; SC: 1.1 mmHg/ml [0.9-1.2] to 1.2 mmHg/ml [1.0-1.3], p<0.01). Ventricular efficiency (VE) increased in ET from 70% [66-73] at rest to 78% [75-80] (p<0.01) during exercise and in SC from 68% [63-72] to 75% [73-78] (p<0.01). Arterial elastance (EA) decreased in both groups (ET: 0.8 mmHg/ml [0.7-0.9] to 0.7 mmHg/ml [0.7-0.9], p<0.05; SC: 1.0 mmHg/ml [0.9-1.2] to 0.9 mmHg/ml [0.8-1.0], p<0.05). Ventricular-arterial coupling (EA/Emax) also decreased in both groups (ET: 0.9 [0.8-1.0] to 0.7 [0.6-0.8], p<0.01; SC: 1.0 [0.9-1.1] to 0.7 [0.7-0.8], p<0.01). This study demonstrates for the first time that LV PV loops can be generated non-invasively during exercise using CMR. ET and SC increase ventricular efficiency and contractility and decrease afterload and ventricular-arterial coupling during moderate supine exercise. These results confirm known physiology. Therefore, this novel method is applicable to be used during exercise in different cardiac disease states, which has not been possible non-invasively before.