JCMR 2020; 22:12 Respiratory motion-compensated high-resolution 3D whole-heart t1p mapping (CME)-Article

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This study evaluated whether exercise stress cardiovascular magnetic resonance (CMR) can help distinguish true dilated cardiomyopathy (DCM) from normal, exercise-related heart remodeling in asymptomatic people with enlarged or weak left ventricles on resting imaging.<br /><br />Researchers studied 60 patients with suspected DCM and 100 healthy volunteers. All participants underwent supine-bike exercise CMR; the patients also had genetic testing for known DCM-causing variants. Healthy subjects were used to define normal age- and sex-specific exercise cardiac index (CI) ranges. Confirmed DCM was defined by both abnormal imaging and a pathogenic gene variant.<br /><br />Key findings:<br />- No patient with confirmed DCM achieved a peak exercise CI above the 35th percentile for age and sex.<br />- Among patients without a known pathogenic mutation, those with peak exercise CI below the 35th percentile looked similar to confirmed DCM cases.<br />- Those with higher exercise CI were younger, more physically active, had stronger myocardial strain, and resembled physiological exercise-induced remodeling rather than disease.<br />- During about 21 months of follow-up, all adverse cardiovascular events occurred only in patients with low exercise capacity; none occurred in those with higher peak exercise CI.<br /><br />The study suggests that peak exercise CI from exercise stress CMR may provide both diagnostic and prognostic information in suspected DCM, especially when resting imaging is ambiguous. It may help separate pathological cardiomyopathy from benign adaptations seen in active individuals, though larger studies with longer follow-up are needed.

Keywords

exercise stress CMR

dilated cardiomyopathy

cardiac index

exercise capacity

left ventricular remodeling

genetic testing

myocardial strain

peak exercise CI

cardiovascular magnetic resonance

prognostic information