JCMR 2020; 22:35. Clinical experience regarding safety and diagnostic value of cardiovascular magnetic resonance in patients with a subcutaneous implanted cardioverter/defibrillator (S-ICD) at 1.5 T (-JCMR 2020 20.10 exercise stress cmr suspected dcm

JCMR 2020 20.10 exercise stress cmr suspected dcm

Pdf Summary

This prospective single-center study evaluated whether exercise stress cardiovascular magnetic resonance (CMR) can help distinguish true dilated cardiomyopathy (DCM) from normal exercise-related cardiac remodeling in active, asymptomatic people whose resting imaging suggested DCM.<br /><br />Sixty asymptomatic patients with suspected DCM underwent exercise stress CMR and genetic testing for DCM-related variants. Another 100 healthy volunteers were used to establish normal age- and sex-specific peak exercise cardiac index (PeakCI) values. Confirmed DCM was defined by both pathogenic genotype and abnormal phenotype.<br /><br />Key findings:<br />- Among 13 patients with confirmed DCM, none had PeakCI above the 35th percentile for age and sex.<br />- In the remaining genotype-negative/phenotype-positive patients, those with low PeakCI (<35th percentile) looked more like confirmed DCM, with lower exercise capacity and worse myocardial strain.<br />- Those with higher PeakCI were younger, more active, and had features more consistent with physiological cardiac remodeling rather than disease.<br />- During about 21 months of follow-up, all 7 adverse cardiovascular events occurred in patients with low PeakCI; no events occurred in those with higher PeakCI.<br /><br />The study suggests that PeakCI measured during exercise stress CMR may provide both diagnostic and prognostic value. It may help clinicians distinguish pathological DCM from benign exercise-induced cardiac enlargement and mild systolic changes, especially when resting imaging and genetic testing are inconclusive.<br /><br />Limitations included the small sample size, short follow-up, and relatively low event rate. The authors conclude that exercise stress CMR is a promising tool for evaluating suspected DCM and warrants validation in larger, longer-term studies.

Keywords

exercise stress CMR

dilated cardiomyopathy

PeakCI

cardiac remodeling

genetic testing

myocardial strain

exercise capacity

cardiovascular events

phenotype

prognostic value