Basics
Description
- Sustained exercise training induces adaptive changes in the cardiovascular system that allow for greater athletic performance. The major adaptations involve the heart, blood, and peripheral vascular system.
- Heart:
- Cardiac hypertrophy that is eccentric with predominant isotonic exercise and concentric with predominant isometric exercise
- Resting sinus bradycardia
- Blood:
- Total blood volume increases due to proportional increases in red cells and plasma.
- Peripheral vascular system:
- Peripheral vascular capacitance increases, resulting in relative decreases in peripheral vascular resistance, allowing movement of a greater stroke volume without increases in systolic pressure.
- Systems affected:
- Cardiovascular
- Hematopoietic
Epidemiology
- Predominant age: Late adolescence to middle aged
- Predominant Sex: Male > Female
- Age-related factors:
- Pediatric: Congenital heart disease predominates
- Middle-aged: Coronary artery disease dominates
Incidence
Sudden death in athletes is rare.
Prevalence
Heart disease in accomplished athletes is unusual.
Risk Factors
Underlying heart disease.
Genetics
- Adaptations to exercise and athletic ability may be partially determined by heredity.
- Inherited heart disease more common in younger athletes.
General Prevention
- Exercise training does not eliminate heart disease. Risk-factor control is still necessary to avoid coronary artery disease.
- Physical fitness improves survival in heart disease.
Pathophysiology
- The ability to increase cardiac output largely determines exercise ability.
- LV hypertrophy is expected and often other cardiac chambers enlarge.
- Vagal nerve tone increases such that resting bradycardia is common.
Etiology
Regular, vigorous exercise training.
Associated Conditions
- Cardiac hypertrophy
- Resting bradycardia
- Increased skeletal muscle mass
Diagnosis
History
- History of athletic training and prowess
- Orthostatic symptoms
Physical Exam
- Athletic physique
- Sinus bradycardia
- Sinus arrhythmia
- Enlarged apical impulse
- RV lift
- Diastolic gallop sounds
- Systolic flow murmurs
Tests
Lab
- EKG: Ventricular hypertrophy patterns (may mimic MI), bradyarrhythmias
- Exercise: Maximum oxygen uptake will identify exercise-trained individuals.
Imaging
- CXR: Cardiac enlargement
- Echo: Distinguish physiologic vs. pathologic ventricular hypertrophy; identify valvular disease, cardiomyopathy and congenital heart disease.
Surgery
- If coronary artery disease is suspected, exercise testing with echo or radionuclide imaging may be indicated, or in some cases coronary angiography.
- Electrophysiologic testing may be required to distinguish pathologic rhythm disturbances from benign ones.
- Tilt table testing may help elucidate the cause of dizziness or syncope encountered in an athlete.
Pathological Findings
Ventricular hypertrophy
Differential Diagnosis
- Abnormal bradyarrhythmias
- Pathologic ventricular hypertrophy
- Valvular heart disease
- Cardiomyopathy
- Coronary artery disease
Treatment
Medication
- Depends on specific underlying heart disease if any
- Significant possible interactions and adverse reactions:
- Refer to manufacturer's literature.
- Some performance-enhancing drugs have potential adverse effects on the heart, such as anabolic steroids and catecholamines.
- Contraindications:
- Refer to manufacturer's profile of each drug.
- Precautions:
- Athletically trained individuals are especially susceptible to drugs with vasodilator or heart rate-slowing properties such as α and β-blockers.
Additional Treatment
General Measures
- Outpatient evaluation
- Distinguish normal physiologic changes from disease
- Many cardiac diseases increase the risk of athletic activity:
- Hypertrophic cardiomyopathy
- Coronary artery anomalies or disease
- Marfan syndrome
- Aortic valve disease
- Complex congenital heart disease
- Pulmonary HTN
- Mitral stenosis
- Pulmonic stenosis
Issues for Referral
Suspected cardiac disease in an athlete
Additional Therapies
- Occasionally athletic training will need to be stopped temporarily until a specific disease is treated with drugs that affect a response in the patient.
- Mega-dose vitamins
- Creatine
Surgery
Corrective surgery for cardiac conditions may permit athletic activity.
In-Patient Considerations
Initial-Stabilization
Treat cardiac arrhythmias
Admission Criteria
- Cardiac arrest
- Heart failure
- Severe chest pain
- Syncope
IV Fluids
Use with electrolyte replacement to treat dehydration
Nursing
Continuous ECG monitoring
Discharge Criteria
- Absence of arrhythmias
- Primary disease identified and steps taken to stabilize and positively correct
Ongoing Care
Follow-Up Recommendations
Depends on the cardiac condition
Patient Monitoring
Occasionally the only way to distinguish normal physiology from disease is to cease exercise training and observe the patient. Sinus bradycardia and chamber enlargement usually regress significantly within weeks.
Diet
Depends on cardiac conditions and training requirements.
Patient Education
Important to describe risks of cardiac disease if patient desires participation in athletic activities.
Prognosis
- Exercise-trained individuals are usually healthier and live longer than sedentary individuals in the absence of significant cardiovascular disease.
- The combination of athletic activities and certain cardiovascular diseases can shorten life.
Complications
- Aortic dissection
- Precipitation of heart failure
- Sudden arrhythmic death
- Syncope
Additional Reading
1Corrado D, Basso C, Pavei A. Trends in sudden cardiovascular death in young competitive athletes after implementation of a preparticipation screening program. JAMA. 2006;296:1593-1601. [View Abstract]2Maron BJ, Zipes DP. 36th Bethesda conference: Eligibility recommendations for competitive athletes with cardiovascular abnormalities. J Am Coll Cardiol. 2005;45:1312-1375.3Maron BJ, Haas TS, Doerer JJ. Comparison of U.S. and Italian experiences with sudden cardiac deaths in young competitive athletes and implications for preparticipation screening strategies. Am J Cardiol. 2009;104:276-280. [View Abstract]4Maron BJ, Doerer JJ, Haas TS. Sudden deaths in young competitive athletes: Analysis of 1866 deaths in the United States, 1980-2006. Circulation. 2009;119:1085-1092. [View Abstract]5Pelliccia A, Di Paolo FM, Quattrini FM. Outcomes in athletes with marked ECG repolarization abnormalities. N Engl J Med. 2008;358:152-161. [View Abstract]6H Maron BJ. Hypertrophic cardiomyopathy and other causes of sudden cardiac death in young competitive athletes, with considerations for preparticipation screening and criteria for disqualification. Cardiol Clin. 2007;25:399-414.
Codes
ICD9
429.3 Cardiomegaly
SNOMED
233931008 athlete's heart (disorder)
Clinical Pearls
- Physiologic adaptations to exercise training can mimic cardiac disease.
- Cardiac hypertrophy and resting bradycardia are the hallmarks of athletic training.
- Underlying heart disease can lead to symptoms or sudden death.
- Screening young athletes for heart disease can save lives, but may lead to a recommendation to cease athletic activities.