Standardizing submaximal exercise intensities for use of supine push–pull exercise during cardiovascular magnetic resonance

Abstract

Background Cardiovascular magnetic resonance (CMR) imaging during supine exercise at (sub)maximal oxygen consumption (VO2) offers unique diagnostic insights. However, maximal VO2 is not achievable in the supine position and standardizing submaximal exercise intensities remains challenging. Using heart rate or workload could be a viable option to translate VO2‐based submaximal exercise intensities. Aim To translate submaximal exercise intensities upright cycling exercise (UCE) to supine push–pull exercise (SPPE), by comparing heart rate or workload determined during UCE, with heart rate and workload during SPPE at similar exercise intensities. Methods and Results Sixteen healthy young adults (20.4 ± 2.2 years; 8 female) underwent cardiopulmonary UCE and SPPE testing [mean ± standard deviation maximal VO2: 3.2 ± 0.6 vs. 5 ± 0.3 L min−1, p < 0.001 and median (interquartile range) of the maximum workload: 310 (244, 361) vs. 98 (98, 100), p < 0.001, respectively]. Heart rate at 40% and 60% of maximal VO2, as determined by UCE, showed low bias (−3 and 0 bpm, respectively) and wide limits of agreement (±26 and ±28 bpm, respectively), in Bland–Altman analysis. VO2/Workload relation was exponential and less efficient during SPPE compared to UCE. Generalized estimated equation analysis predicted model‐based mean workload during SPPE, with acceptable 95% confidence interval. Conclusion Heart rate during UCE at submaximal exercise intensities can reasonably well be used to for SPPE in healthy subjects. Using workload, an ergometer specific, model‐based mean can be used to determine exercise intensities during SPPE. Individual variations in response to posture and movement change are high. During clinical interpretation of exercise CMR, individual exercise intensity has to be considered.

Cardiac dysfunction during exercise in young adults with bronchopulmonary dysplasia

“…Our study was able to correlate duration of oxygen dependency after birth with ventricular response to exercise during young adulthood. Furthermore, we used a validated method to ascertain repeatable submaximal exercise intensities related to subject-specific V ′ O 2 max, instead of less reproducible criteria such as exhaustion or fixed heart rate zones [ 17 ].…”

“…A MRI-compatible, push-pull ergometer (Lode BV, Groningen, the Netherlands) was used to enable taller subjects to perform the tests. To standardise exercise intensities, a recently validated V ′ O 2 -based approach was used [ 17 ]. Workload was calculated using the formula: W=183.3× 10 log( V ′ O 2 kg −1 )–181.6 [ 17 ].…”

“…To standardise exercise intensities, a recently validated V ′ O 2 -based approach was used [ 17 ]. Workload was calculated using the formula: W=183.3× 10 log( V ′ O 2 kg −1 )–181.6 [ 17 ]. Exercise intensities were chosen to remain within the technical limits of the push-pull ergometer (5–100 W) [ 17 ].…”

“…Workload was calculated using the formula: W=183.3× 10 log( V ′ O 2 kg −1 )–181.6 [ 17 ]. Exercise intensities were chosen to remain within the technical limits of the push-pull ergometer (5–100 W) [ 17 ]. Imaging was performed directly after cessation of exercise because imaging during exercise led to extensive movement artefacts.…”