cardiovascular disorders
Athlete’s Heart
Diagnosis of Athlete’s Heart
Clinical evaluation Usually ECG Sometimes echocardiography Rarely, cardiac magnetic resonance imaging Rarely, stress testing Findings are typically detected during routine screening or during evaluation of unrelated symptoms. Most athletes do not require extensive testing, although ECG is often warranted. If symptoms suggest a cardiac disorder (eg, palpitations, chest pain), ECG, echocardiography, and exercise stress testing are done. Athlete's heart is a diagnosis of exclusion; it must be distinguished from disorders that cause similar findings but are life threatening (eg, Hypertrophic Cardiomyopathy , Numerous changes in rhythm and ECG morphology can occur; they correlate poorly with level of training and cardiovascular performance. The most common ECG finding is Sinus bradycardia Rarely, heart rate is<40 beats/minute. Sinus arrhythmia often accompanies the slow heart rate. Resting bradycardia may also predispose to Atrial or ventricular ectopy (including couplets and bursts of nonsustained ventricular tachycardia); pauses after ectopic beats do not exceed 4 seconds Wandering supraventricular pacemaker Other ECG findings that may occur include First-degree atrioventricular (AV) block (in up to one third of athletes) Second-degree AV block (mainly type I); this finding occurs during rest and disappears with exercise High-voltage QRS with inferolateral T-wave changes (reflecting LV hypertrophy) Deep anterolateral T-wave inversion Incomplete right bundle branch block However, Third-degree AV block is abnormal and should be investigated thoroughly. These ECG and rhythm changes have not been associated with adverse clinical events, suggesting that various arrhythmias are not abnormal in athletes. The arrhythmias are usually abolished or substantially reduced after a relatively brief period of deconditioning. Echocardiography can usually distinguish athlete’s heart from cardiomyopathies (see table Features Distinguishing Athlete's Heart From Cardiomyopathy ), but the distinction is not always clear because there is a continuum from physiologic to pathologic cardiac enlargement. The zone of overlap between athlete’s heart and cardiomyopathy is left ventricular septal thickness: In men, 13 to 15 mm In women, 11 to 13 mm In this overlap area, the presence of mitral valve systolic anterior motion strongly suggests Hypertrophic Cardiomyopathy . Also, diastolic indexes may be abnormal in cardiomyopathy but are usually normal in athlete's heart. In general, echocardiographic changes correlate poorly with level of training and cardiovascular performance. Trace mitral regurgitation and tricuspid regurgitation are commonly detected. Of note, reduction of physical training will result in regression of cardiac enlargement in patients with athlete's heart but not in those with cardiomyopathy. Exercise echocardiography may help to differentiate athlete's heart from Although confirmation in large studies is pending, data so far suggest that CMR may also help differentiate athlete's heart from cardiomyopathy. In hypertrophic cardiomyopathy ( Diagnosis references ), CMR may identify focal hypertrophy not identified on the echocardiogram, particularly in the apex, anterior free wall, and posterior septum. Delayed imaging after injection of contrast may show a typical pattern of mid-wall fibrosis in some patients with hypertrophic cardiomyopathy, particularly in left ventricular wall segments that exhibit maximal hypertrophy. However, this finding is absent in up to 60% of patients with hypertrophic cardiomyopathy. Delayed enhancement on CMR is also evident in nonischemic dilated cardiomyopathy and may help differentiate dilated cardiomyopathy from athlete's heart. However, the finding is absent in 68% of patients with genetically proven dilated cardiomyopathy. T1 and T2 mapping, extracellular volume quantification, late gadolinium enhancement, deformation imaging and diffusion tensor imaging are all promising techniques to differentiate between athlete's heart and hypertrophic cardiomyopathy. Further studies are required to better determine the ability of these techniques to detect hypertrophic cardiomyopathy in athletes ( Diagnosis references ). Although exercise capacity as measured by stress testing does not differentiate between athlete's heart and dilated cardiomyopathy, reduced cardiac contractile reserve with exercise observed on CMR imaging may be useful in establishing a diagnosis of dilated cardiomyopathy in an athlete. During Stress Testing , heart rate remains lower than normal at submaximal stress and increases appropriately and comparably to heart rate in nonathletes at maximal stress; it rapidly recovers after exercise. Blood pressure response is normal if: Systolic blood pressure increases Diastolic blood pressure falls Mean blood pressure stays relatively constant Many resting ECG changes decrease or disappear during exercise; this finding is unique to athlete's heart, distinguishing it from pathologic conditions. However, pseudonormalization of T-wave inversions could reflect myocardial ischemia and thus warrants further investigation in older athletes. Also, a normal exercise stress test result does not rule out a cardiomyopathy. 1.Brosnan MJ, Rakit D: Differentiating athlete's heart from cardiomyopathies − The left side.Heart Lung Circ27(9):1052–1062, 2018. doi: 10.1016/j.hlc.2018.04.297 2.Millar LM, Fanton Z, Finocchiaro G, et al: Differentiation between athlete's heart and dilated cardiomyopathy in athletic individuals.Heart106(14):1059–1065, 2020. doi: 10.1136/heartjnl-2019-316147 3.Czimbalmos C, Csecs I, Toth A, et al: The demanding grey zone: Sport indices by cardiac magnetic resonance imaging differentiate hypertrophic cardiomyopathy from athlete's heart.PLoS ONE14(2): e0211624. 2019. 4.Bakogiannis C, Mouselimis D, Tsarouchas A, et al: Hypertrophic cardiomyopathy or athlete's heart? A systematic review of novel cardiovascular magnetic resonance imaging parameters.Eur J Sports SciDec 2;1–12, 2021. doi: 10.1080/17461391.2021.2001576 5.Baggish AL, Battle RW, Beaver TA, et al: Recommendations on the use of multimodality cardiovascular imaging in young adult competitive athletes: A report from the American Society of Echocardiography in collaboration with the Society of Cardiovascular Computed Tomography and the Society for Cardiovascular Magnetic Resonance.J Am Soc Echocardiogr33 (5): 523–549, 2020. doi: 10.1016/j.echo.2020.02.009 