Submaximal in addition to peak stress echocardiogram differentiates pathological LV dilatation from physiological dilatation and could help facilitate early heart failure diagnosis

Abstract

Abstract Background Left ventricular dimensions in athletes overlap with those observed in patients with dilated cardiomyopathy (DCM). Among athletes with concomitant baseline low left ventricular ejection fraction (LVEF), the differentiation between the two entities may be difficult. Purpose We compared the role of changes in left ventricular ejection fraction (LVEF) during submaximal and maximal stress exercise echocardiography to facilitate the differentiation between athlete’s heart and DCM individuals with asymptomatic exercising individuals with a dilated left ventricle (LV) and borderline/low LVEF (48-54%). Methods 47 highly active asymptomatic individuals with DCM and mildly impaired LVEF, 52 athletes with borderline/low LVEF (grey zone athletes) and 44 athletes with a normal EF (healthy athletes) underwent a stress echocardiography on a semi-recumbent bike with an incremental ramp protocol of 25watt/min.Echocardiographic images were obtained at rest, submaximal (80% of predicted heart rate) and maximal exercise. Maximal exercise was classified as a heart rate 90-100% of the calculated maximum heart rate for their age. Results Both grey zone and healthy athletes achieved a greater increase in peak LVEF compared with DCM individuals (20.4% and 20.2% vs 4.6% respectively). The mean increase in LVEF from submaximal exercise to maximal exercise in healthy athletes and grey zone athletes was 7.0% and 3.4% (p<0.001) respectively whereas individuals with DCM showed a mean reduction in LVEF of -4.3% during this period. 8 (17%) of DCM individuals were able to increase LVEF ≥10% from rest to peak exercise, however most (96%) revealed a drop in LVEF as effort progressed from submaximal to maximal exercise.97.7% of control athletes were able to augment an EF ≥10% from rest to maximum exercise and continued to show an increase in LVEF from submaximal to maximal exercise. Whereas 47 (90.4%) grey zone athletes also showed an increase in LVEF >10% from rest to peak exercise, the remaining 5 (9.6%) were unable to augment this response and revealed a drop in contractile reserve from submaximal to maximal exercise, suggesting the possibility of an underlying diagnosis of DCM. Conclusion Healthy athletes and grey zone athletes show a greater contractile reserve compared to DCM athletes during exercise.Over 90% athletes and 10% DCM patients reveal an increase in LVEF >10% from baseline to peak exercise.Comparison of changes in LVEF between submaximal and maximal exercise reveals that 96% DCM patients and 9.6% grey zone athletes show a drop in in LVEF during this period. Failure to augment LVEF between submaximal and maximal exercise may identify grey zone athletes with DCM.