Differentiation between athlete’s heart and dilated cardiomyopathy in athletic individuals

Background: Distinguishing early dilated cardiomyopathy (DCM) from physiological left ventricular (LV) dilatation with mildly reduced LV ejection fraction (‘grey-zone’) is challenging. We evaluated the role of a cascade of investigations to differentiate these two entities.

Methods and Results: Thirty-five asymptomatic active males with DCM, 25 male athletes in the ‘grey-zone’ and 24 male athlete controls with normal LV ejection fraction were investigated with NT-proBNP, electrocardiography (ECG) and exercise echocardiography. ‘Grey-zone’ athletes and DCM patients underwent cardiovascular magnetic resonance and Holter monitoring. Larger LV cavity dimensions and lower LV ejection fraction were the only differences between control and ‘grey-zone’ athletes. None of the ‘grey-zone’ athletes had an abnormal NT-proBNP, increased ectopic burden/complex arrhythmias or pathological late gadolinium enhancement. These features were absent in 71%, 71% and 50% of DCM patients respectively. 95% of ‘grey-zone’ athletes and 60% DCM patients had a normal ECG. During exercise echocardiography, 96% of the ‘grey-zone’ athletes increased LV ejection fraction by >11% from baseline to peak exercise compared with 23% DCM patients. Peak LV ejection fraction was >63% in 92% ‘grey-zone’ athletes compared with 17% DCM patients. Failure to increase LV ejection fraction >11% from baseline to peak exercise or achieve a peak LV ejection fraction >63% had a sensitivity of 77% and 83% respectively and specificity of 96% and 92% respectively for predicting DCM.

Conclusion: Comprehensive assessment using a cascade of routine investigations revealed that exercise stress echocardiography has the greatest discriminatory value in differentiating between ‘grey-zone’ athletes and asymptomatic DCM patients.