Cardiac stress testing after surgery for congenital heart disease

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

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.

Stress Echocardiography in Pediatric and Adult Congenital Heart Disease: A Complement in Anatomical and Functional Assessment

Functional classification of children and adults with repaired and unrepaired congenital heart disease is a challenge for clinicians, due to the heterogeneity of congenital heart disease. Functional studies may be complemented with a stress echocardiogram, which analyzes the hemodynamic behavior of surgical repair zones, residuals, and sequelae. The integration of the anatomical and functional classification criteria developed for congenital heart disease and the results of a stress echocardiogram can establish a more precise functional classification. Stress echocardiograms also provide early diagnosis of functional complications of the congenital heart, allowing timely management decisions. This paper reviews the most important aspects of stress echocardiograms in pediatric and adult congenital heart disease, seeking to spark cardiologists' interest in extending its applications in congenital heart disease.