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Updated: Apr 19 2024

Cardiac Conditions

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  • Summary
    • Cardiac conditions are the most common cause of sudden death in young athletic patients and comprise of hypertrophic cardiomyopathy (most common), coronary artery disease, and commotio cordis.
    • Diagnosis requires a thorough history and physical exam to identify a history of chest pain, palpitations, syncope during exercise, and evaluation for murmurs. An EKG or echocardiogram should be performed when there is a high suspicion of hypertrophic cardiomyopathy.
    • Treatment is focused on prevention with avoidance of vigorous exercise when hypertrophic cardiomyopathy is diagnosed. If commotio cordis develops, prompt treatment with cardiac defibrillation is required for survival. 
  • Overview
    • Common conditions affecting athletes include
      • syncope
      • hypertrophic cardiomyopathy
      • coronary artery disease
      • long QT syndrome
      • commotio cordis
      • sudden cardiac death
    • Presentation
      • symptoms
        • history and physical exam is the best screening tool to identify cardiovascular problems in high school athletes
        • chest pain
        • palpitations
        • syncope
      • physical exam
        • pre-participation physicals
          • diastolic murmur warrants further workup
          • II/VI systolic murmur
    • Evaluation
      • EKG
        • normal EKG findings in endurance athletes
          • ventricular hypertrophy
          • primary AV block
          • nonspecific STT wave changes in the lateral leads on ECG
          • resting sinus bradycardia at 40 beats per minute
  • Syncope
    • Overview
      • sudden loss of consciousness caused by a sudden loss of blood pressure
      • a syncopal episode in a young athlete is a red flag for a serious cardiac condition.
    • Epidemiology
      • incidence
        • annual incidence of 7%
    • Demographics
      • age
        • any age
      • sex
        • more common in females than in males
      • risk factors
        • cardiac conditions
        • dehydration
        • female gender
    • Etiology
      • pathophysiology
        • transient loss of consciousness due to decreased cerebral perfusion
        • can be caused by any condition disrupting cerebral perfusion
        • 50% are neurocardiogenic also known as vasovagal syncope
          • increased vasodilation with bradycardia due to decreased sympathetic and increased parasympathetic tone
          • risk factors
            • when standing for prolonged periods
            • hot environments
      • associated conditions
        • cardiovascular disorder
          • arrhythmias
          • cardiac structural abnormalities
            • including myocardial infarction, hypertrophic cardiomyopathy, valvular disease, pulmonary embolism, commotio cordis
        • cerebrovascular disease
          • including stroke, transient ischemic attack, vertebrobasilar insufficiency
        • disruption of vascular tone and blood flow
          • including orthostatic hypotension, carotid sinus syndrome, anemia
    • Presentation
      • symptoms
        • lightheadedness
        • dizziness
        • palpitations
        • sweating
      • physical examination
        • unconsciousness
        • cold clammy skin
    • Treatment
      • medical evaluation
        • requires a medical evaluation prior to returning to athletic activity
  • Hypertrophic Cardiomyopathy
    • Overview
      • a genetic condition causing mutations in the cardiac muscle leading to increased ventricular wall thickness resulting in outflow obstruction, diastolic dysfunction, and increased risk of sudden cardiac death
      • most common cause of cardiac sudden death in young athletic patients
    • Epidemiology
      • incidence
        • 1 in 500
      • demographics
        • age
          • present from birth
          • diagnosis is usually between 20-30 years of age
        • sex
          • male:female is 1 to 1
            • females more likely to be symptomatic
      • risk factors
        • hypertension
        • genetic predisposition
    • Etiology
      • pathophysiology
        • abnormal thick or thin cardiac myofilament proteins resulting in abnormal structure and function of the cardiac muscle with hypertrophy of the left ventricular wall and septum
        • leads to asymmetric hypertrophy resulting in left ventricular outflow obstruction
          • most commonly affects the interventricular septum
            • 66% of patients
      • genetics
        • inheritance pattern
          • autosomal dominant with variable penetrance
            • predominantly missense mutations
            • less likely to be frameshift mutation
        • mutations
          • thousands of possible mutations affecting more than a dozen genes including
            • Cardiac troponin T – TNNT2 gene
            • Cardiac troponin I – TNNTI3 gene
            • Myosin regulatory light chain – MYL2 gene
            • Myosin essential light chain – MYL3 gene
      • associated conditions
        • increased risk for sudden cardiac death and arrhythmias
    • Presentation
      • history
        • family history
        • cardiac murmur
      • symptoms
        • dyspnea on exertion
        • chest pain
        • dizziness
        • presyncope or syncope
      • physical exam
        • II/VI systolic crescendo-decrescendo murmur
          • 25% of patients with obstruction at rest
          • 70% of patients with obstruction during provocative maneuvers
            • decreased preload increases murmur intensity
              • Valsalva maneuver
              • diuretics
              • standing
                • a murmur that increases with standing or Valsalva maneuver should raise concern for hypertrophic cardiomyopathy
            • increases with decreased afterload or increased preload
              • caused by dynamic obstruction of blood outflow caused by an enlarged ventricle
              • squatting or handgrip maneuver
        • double carotid pulse
        • arrhythmia
        • double apical pulse
    • Imaging
      • echocardiogram
        • will show nondilated, thickened left ventricular wall thickness compared to normal individuals of the same age.
        • 80% diagnostic accuracy
        • evaluate the structure of cardiac chambers, along with systolic and diastolic function
        • determines the degree of outflow obstruction
        • evaluates for valvular disease
      • cardiac mri
        • gold standard for diagnosis
        • performed in patients in which hypertrophic cardiomyopathy is suspected with inconclusive echocardiogram
    • Studies
      • electrocardiogram
        • most sensitive diagnostic test
        • left ventricular hypertrophy with right atrial enlargement is highly suggestive of hypertrophic cardiomyopathy
          • prominent Q-waves in inferior and lateral leads
          • left axis deviation
          • atrial enlargement
          • inverted t-waves
      • ambulatory electrocardiogram
        • recommended in all patients diagnosed with hypertrophic cardiomyopathy
        • worn for 24-48 hours
        • used in the assessment of ventricular arrhythmias and sudden cardiac death
      • stress test
        • exercise is preferred over pharmacologic stress test
        • used for assessment of left ventricular outflow obstruction tract gradient
          • useful for risk stratification
    • Diagnosis
      • diagnosis is made based on an echocardiogram, electrocardiogram, genetic testing, and family history
    • Treatment
      • lifestyle modifications
        • indications
          • Asymptomatic patients, mild left ventricular hypertrophy, and no outflow obstruction
        • management
          • routine clinical observation
          • repeat echocardiogram as indicated by changes in symptoms
          • maintain hydration
          • avoid vigorous exercise
            • considered an absolute contraindication to vigorous exercise and sports
        • outcomes
          • may participate in sports that require mild to moderate physical activity
      • medical therapy
        • indications
          • symptomatic patients (dyspnea, fatigue, chest pain, syncope)
        • management
          • beta-blockers (metoprolol)
            • first line
          • calcium channel blockers
        • outcomes
          • non-vasodilating beta-blockers can improve symptoms
            • only provides symptomatic relief
    • Complications
      • cardiac complications
        • includes sudden cardiac death, arrhythmias, congestive heart failure, stroke
    • Prognosis
      • 1-2% annual mortality rate
  • Coronary Artery Disease
    • Epidemiology
      • 2nd most common cause of sudden cardiac death
      • most common in older patients
    • Pathophysiology
      • coronary artery disease (CAD)
        • usually seen in older patients
        • risk factors
          • hypertension
          • family history
      • left main coronary artery with abnormal origin is a risk because the artery can become compressed and lead to ischemia
    • Presentation
      • symptoms
        • mostly asymptomatic
        • but when symptoms present they are commonly
          • chest pain
          • palpitations
          • syncope
    • Imaging
      • coronary angiography and MR angiography are gold standards
    • Treatment
      • lifestyle changes
        • healthy eating, stress reduction, quit smoking, lose weight
      • medications
        • b-blocker, aspirin, ACE inhibitors, nitroglycerin, calcium channel blockers
      • surgery
        • angioplasty and stenting
        • coronary artery bypass grafting
  • Commotio Cordis
    • Overview
      • it results in cardiac ventricular fibrillation and is universally fatal unless immediate defibrillation is performed
      • caused by direct impact during ventricular repolarization
      • a rare but catastrophic condition that is caused by blunt chest trauma
    • Epidemiology
      • incidence
        • less than 30 cases per year
      • demographics
        • age
          • average age is 15 years old
            • most common in children and adolescents due to high number of athletes
        • sex
          • male:female ratio is 20 to 1
      • risk factors
        • contact sports
        • younger age
    • Etiology
      • pathophysiology
        • mechanism of injury
          • traumatic blow to the anterior chest during ventricular repolarization leading to ventricular depolarization resulting in ventricular fibrillation
      • pathoanatomy
        • anterior chest wall blow occurring during the upstroke of the T-wave with enough energy (>50 joules) leading to myocardial cell membrane stretch
          • the upstroke of the T-wave is 1% of the cardiac cycle
          • smaller balls increase risk due to decreased surface area of impact
          • higher energy impacts are more likely to cause structural damage and not isolated ventricular fibrillation
        • results in activation of ion channels through mechanical-electrical coupling resulting in aberrant depolarization resulting in ventricular fibrillation
    • Presentation
      • history
        • patient experiences a sudden blow to the chest, typically during an athletic event
      • symptoms
        • loss of consciousness
      • physical exam
        • pulselessness
        • unconsciousness
        • death
    • Studies
      • electrocardiogram
        • will show ventricular fibrillation
    • Diagnosis
      • diagnosis is made by witnessed blow to the chest followed by collapse with electrocardiogram showing ventricular fibrillation
    • Treatment
      • CPR vs.cardiac defibrillation
        • the best method of treatment is cardiac defibrillation
      • return to sport
        • no restrictions from returning to sport
        • athletes should take precautions against future blows to the chest
    • Prevention
      • chest protectors in baseball and hockey have not yielded the protective results desired
    • Prognosis
      • poor prognosis with a mortality rate of 59%
      • improved mortality rate with early defibrillation
  • Long QT Syndrome
    • overview
      • a prolongation in the ventricular action potential duration, QT interval, potentially leading to cardiac arrhythmias 
    • Epidemiology
      • incidence
        • 1 in 2,500 to 10,000
      • demographics
        • age
          • diagnosis is usually under 20 years of age
        • sex
          • more uncommon in females than in males
      • risk factors
        • genetic predisposition
        • medications
          • anti-arrhythmic, antibiotics (macrolides/fluoroquinolones), antipsychotics
    • Etiology
      • pathophysiology
        • congenital
          • genetic mutation coding for the ion channel proteins leading to increased intracellular positive ion charge, prolonging the QT interval, and increasing risk of arrhythmia
        • acquired
          • electrolyte derangement or medications blocking potassium ion channel leading to increased intracellular positive ion charge and prolonged QT interval during repolarization
      • Genetics
        • inheritance pattern
          • most mutations are autosomal dominant
        • mutations
          • LTQ1 – 45%
            • Chromosome 11
            • Encodes for KCNQ1
              • Loss of function mutation
              • Component of potassium efflux channel
          • LTQ2 – 25-40% 
            • Chromosome 7
            • Encodes KCNH2
              • Component of potassium influx channel
          • LTQ3 – 5-10%
            • Chromosome 3
            • Encodes SCN5A
            • Component of sodium channel
      • associated conditions
        • Romano Ward Syndrome
          • an abnormality of ventricular repolarization that can lead to
            • sudden cardiac death if not recognized and treated
            • torsades de pointes
            • ventricular tachycardia
    • Presentation
      • history
        • majority of patients are asymptomatic
        • family history or medications leading to acquired long QT syndrome
      • symptoms
        • often times asymptomatic
        • syncope or near-syncope with exercise
        • cardiac arrest
        • palpitations
      • physical examination
        • arrhythmia
    • Studies
      • labs
        • basic metabolic panel and magnesium level
          • further cause QT prolongation
    • Diagnosis
      • ECG is gold standard
    • Treatment
      • sports return to play
        • determination of play by genetic makeup, presentation, and need for pacemaker
        • monitoring with intermittent electrocardiogram
        • no restriction from exercise 
    • Complications
      • torsades de pointes
        • can occur from prolonged QT syndrome
        • 50% are asymptomatic
  • Sudden Cardiac Death
    • Overview
      • defined as death resulting from cardiovascular cause occurring within one hour of symptom onset
    • Epidemiology
      • incidence
        • 0.76 to 13 per 100,000
        • 2.8x more common in adolescent and teenage athletes than in non-athletes
      • demographics
        • age
          • Birth to 13 years old is usually due to a congenital abnormality
          • 14 to 24 years old is usually due to hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, congenital coronary anomalies, wolf-parkinson white, and Marfan syndrome
        • sex
          • more common in males than females
        • risk factors
          • increased with age
          • increased risk in males
          • anomalous origin of coronary artery
          • hypertrophic cardiomyopathy
    • Etiology
      • pathophysiology
        • mechanism
          • sudden generation of cardiac arrhythmia leading to ventricular ectopy then sustained ventricular arrhythmia leading to ventricular tachycardia or ventricular fibrillation
          • usually secondary to a pre-existing condition
    • Presentation
      • history
        • family history of sudden cardiac death
        • prior restriction from sports due to cardiac
        • history of heart murmur
      • symptoms
        • syncope
        • chest pain, tightness, pressure or discomfort
        • elevated blood pressure
        • heart murmur
        • pulselessness
      • physical exam
        • blood pressure assessment
        • pulse check
        • auscultation for heart murmur
    • Imaging
      • cardiac MRI
      • coronary angiography
      • echocardiogram
    • Studies
      • labs
        • cardiac enzyme assay
        • genetic testing
          • brugada, lqts, arvc
      • other studies
        • exercise stress test
        • electrophysiology testing
        • electrocardiogram
    • Treatment
      • cardiac resuscitation involving CPR and AED defibrillation
    • Prognosis
      • overall, poor prognosis with >90% mortality rate
      • early recognition and use of an AED significantly improve survival
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