Differentiating athlete's heart & hypertrophic cardiomyopathy with cardiac

Sudden cardiac deaths (SCD) in young athletes are highly visible catastrophes.(1) More than 2,000 people under the age of 25 die of SCD each year.(2) These events create headlines, and places significant amount of emotional stress on family, classmates, and society.(1, 3) Hypertrophic cardiomyopathy (HCM) is the most common cause of SCD in young athletes, accounting for more than a third of the cases.(4) The diagnosis is difficult to make in young athletes as they have similar phenotype of mild hypertrophy of the ventricular wall. The consequences of a misdiagnosis can be life changing. If the patient has HCM and was misdiagnosed as athlete's heart, then they are at an increased risk of SCD without appropriate follow up and therapy. If the patient has athlete's heart and was misdiagnosed as HCM, then this would risk losing the benefits of sports, quality of life and unnecessary fear of SCD. I. Hypothesis: 1. The progression and regression of hypertrophy and change in myocardial strain due to training and detraining differs between athlete's heart and HCM hearts 2. Regression of hypertrophy and changes in myocardial strain can be detected early during detraining with CMR. II. Specific Aims: We will test our hypotheses with the following specific aims: 1. Determine the exercise tolerance, progression and regression of hypertrophy and myocardial strain due to training and detraining in non-transgenic mice with CMR and echocardiography 2. Determine the exercise tolerance, progression and regression of hypertrophy and myocardial strain due to training and detraining in hypertrophic cardiomyopathy mouse