Cardiac MRI of the athlete's heart

Abstract

The increase in pre-participation cardiovascular screening using the Lausanne protocol will ultimately lead to an increased use of cardiac MRI and MDCT in the cardiovascular work-up of athletes. The role of cardiac MRI is well established in the evaluation of cardiomyopathies, myocarditis, aortic stenosis and diseases of the aorta. 3D-MRCA can detect coronary artery anomalies of wrong sinus origin, but is limited in identifying coronary artery disease. As coronary artery disease is the most common cause of sudden cardiac death in athletes over 35 years of age, MDCT (including coronary artery calcium score and coronary angiography) is a useful tool for cardiovascular risk stratification and assessment of the extent of coronary artery disease. At the expense of higher radiation exposure, MDCT can also be used for assessment of cardiac function. Chapter 2. Brief coaching using an adapted short axis cardiac MRI protocol with specific instructions, provides reproducible volume, function and mass quantification of the RV and LV to facilitate standardized cardiac MRI analysis for both clinical practice and research purposes. Chapter 3. The endurance athlete’s heart shows increased ventricular volumes, diameters, wall-mass and wall-thickness. In young athletes of 18 to 40 years of age, high training-hours/week, high BSA and male gender result in an increased overlap with standard thresholds for cardiomyopathy. Chapter 4. Only athletes show a significant decrease in BSA corrected values for ventricular volumes and LV wall-mass with increasing age. As non-athletes show no significant differences with increasing age, this effect in athletes probably reflects the change in training intensity per training-hour more than a direct effect of age. As the mature athletes still have significantly higher ventricular volumes and wall-mass than their matched non-athletes and significantly lower values as compared to young athletes, they form a distinct group of athletes requiring separate reference values. Chapter 5. BSA-corrected and training intensity and gender-stratified values are required for the correct assessment of normal adaptation of the atria to prolonged endurance training. Atrial and ventricular enlargement remains balanced (balanced adaptation) with higher training intensity, for both comparison of left to right side of the heart as well as for atrium to ventricle size for each side. Chapter 6. In healthy individuals and endurance athletes, cardiac MRI systematically shows larger values of ventricular and atrial dimensions and volumes compared to echocardiography, while wall-thickness and wall-mass are smaller. Chapter 7. A 10 minute 3D-MRCA protocol can be used to screen for CAA in asymptomatic athletes under 35 years old. Chapter 8 and 9. With this thesis we provide reproducible age, gender, training hours/week and body surface area specific cardiac MRI reference values of normal cardiac adaptation to physical training. This will help distinguish an athlete’s heart from cardiomyopathy and reduce inconclusive cardiac MRI reports due to the grey area between physiological adaptation and cardiomyopathy. The value of 3D-MRCA in detecting proximal coronary artery anomalies can be used as part of the standard cardiac MRI protocol to screen young competitive athletes and non-athletes. Screening for stenosis is currently less feasible with 3D-MRCA.