Exercise cardiac magnetic resonance imaging: a feasibility study and meta-analysis

Abstract

Cardiac stress testing improves detection and risk assessment of heart disease. Magnetic resonance imaging (MRI) is the clinical gold-standard for assessing cardiac morphology and function at rest; however, exercise MRI has not been widely adapted for cardiac assessment because of imaging and device limitations. Commercially available magnetic resonance ergometers, together with improved imaging sequences, have overcome many previous limitations, making cardiac stress MRI more feasible. Here, we aimed to demonstrate clinical feasibility and establish the normative, healthy response to supine exercise MRI. Eight young, healthy subjects underwent rest and exercise cinematic imaging to measure left ventricular volumes and ejection fraction. To establish the normative, healthy response to exercise MRI we performed a comprehensive literature review and meta-analysis of existing exercise cardiac MRI studies. Results were pooled using a random effects model to define the left ventricular ejection fraction, end-diastolic, end-systolic, and stroke volume responses. Our proof-of-concept data showed a marked increase in cardiac index with exercise, secondary to an increase in both heart rate and stroke volume. The change in stroke volume was driven by a reduction in end-systolic volume, with no change in end-diastolic volume. These findings were entirely consistent with 17 previous exercise MRI studies (226 individual records), despite differences in imaging approach, ergometer, or exercise type. Taken together, the data herein demonstrate that exercise cardiac MRI is clinically feasible, using commercially available exercise equipment and vendor-provided product sequences and establish the normative, healthy response to exercise MRI.

Exercise cardiovascular magnetic resonance: feasibility and development of biventricular function and great vessel flow assessment, during continuous exercise accelerated by Compressed SENSE: preliminary results in healthy volunteers

“…The haemodynamic response to exercise demonstrated a minimal change in LVEDV and a rise in LVSV driven by a fall in LVESV during exercise, which is in keeping with a recent Ex-CMR meta-analysis of 16 Ex-CMR studies [31]. Indeed, our study demonstrated a non-significant decrease in LVEDV with exercise as was demonstrated by the majority of Ex-CMR studies in the Ex-CMR meta-analysis.…”

Cardiac output measurement during exercise in COPD: A comparison of dye dilution and impedance cardiography

“…Using the regression equations of cardiac output against VO 2 in Figure for both methods, at a normal resting VO 2 of 300 mL/min, cardiac output by impedance cardiography would be 5.1 L/min, while that by dye dilution would be only 4.1 L/min. A similar calculation from the Charloux et al paper (their Figure ) estimates cardiac output at this VO 2 would be 6.3 L/min, while that from Bogaard et al (their Figure ) estimates cardiac output would be 4.7 L/min. Taken together with the relatively high body mass of the subjects in our study of 77.0 kg, these calculations suggest that the impedance‐based values in our study may be more accurate than those derived from dye dilution.…”

“…Studies have indicated that both techniques offer reliable and valid determinations of cardiac output and are accurate to within 5%‐10% at rest and during exercise . Nowadays, cardiovascular magnetic resonance imaging (CMR) is generally considered the clinical gold standard for quantitative assessment of right and left ventricular dimensions and global systolic function at rest providing a surrogate measure of cardiac output in healthy and diseased . CMR can noninvasively obtain stroke volume and cardiac output from both the pulmonary and systemic circulation, using either cine imaging of the ventricles or flow imaging in the aorta and pulmonary trunk.…”

“…CMR can noninvasively obtain stroke volume and cardiac output from both the pulmonary and systemic circulation, using either cine imaging of the ventricles or flow imaging in the aorta and pulmonary trunk. The clinical feasibility and reliability of CMR has been examined in healthy subjects during supine or upright cardiopulmonary exercise testing using dedicated ergometers with promising results . To what extent CMR can provide valid measures during exercise against the gold standard measures such as the direct Fick or dye dilution methods in clinical population remains to be investigated.…”

Reply to “Letter to the Editor: Exercise MRI in healthy individuals—will the outlier please stand up?”

“…Submitted 2 January 2019; accepted in final form 28 January 2019 REPLY: We thank LaFountain et al (2) for their interest in our recent manuscript on exercise cardiac magnetic resonance imaging (1). The principle critique raised by the authors centers on the appropriateness of our inclusion of their study in our meta-analysis of the normative cardiac response to supine exercise MRI.…”