Preprint Exercise stress in healthy adults: normal ranges for real time cardiac magnetic resonance imaging, 2023, Schweitzer et al.

Exercise stress in healthy adults: normal ranges for real time cardiac magnetic resonance imaging
Ronny Schweitzer; Antonio de Marvao; Mit Shah; Paolo Inglese; Peter Kellman; Alaine Berry; Ben Statton; Declan P O'Regan

Background:
Real-time (RT) exercise cardiac magnetic resonance imaging (exCMR) is an emerging approach for cardiac stress testing as part of a comprehensive cardiovascular imaging assessment. It has advantages over alternative approaches due to its high spatial resolution and use of non-pharmacological stress. As access to exCMR increases, there is a need to establish reference ranges in healthy adults for clinical interpretation.

Methods:
We analysed data from 162 healthy adults who had no known cardiovascular disease, did not harbour genetic variants associated with cardiomyopathy, and who completed an exCMR protocol using a pedal ergometer. Participants were imaged at rest and after exercise with left ventricular parameters measured using commercial software by two readers. Prediction intervals were calculated for each parameter.

Results
Exercise caused an increase in heart rate (64±9 bpm vs 133±19 bpm, P < 0.001), left ventricular end-diastolic volume (140±32 ml vs 148±36 ml, P < 0.001), stroke volume (82±18 ml vs 102±26 ml, P < 0.001), ejection fraction (59±6% vs 69±7%, P < 0.001), and cardiac output (5.2±1.2 l/min vs 10.0±3.1 l/min, P < 0.001), with a decrease in left ventricular end-systolic volume (58±18 ml vs 46±16 ml, P < 0.001). There was an effect of gender and age on response to exercise across most parameters. Measurements showed moderate to excellent intraand inter-observer agreement.

Conclusion:
In healthy adults, an increase in cardiac output after exercise is driven by a rise in heart rate with both increased ventricular filling and emptying. We establish normal ranges for exercise response, stratified by age and gender, as a reference for the use of exCMR in clinical practice.

Link | PDF (Preprint: MedRxiv)

 

I think this would be an interesting technique to apply in ME and in POTS to see if there is any significant abnormality in cardiac function when confined to the supine position, without orthostatic effects. A second-day assessment to capture any PEM effects would also be required.