294.3 🏥 內科專科考前版

294.3.1 Mechanistic Deep Dive

294.3.1.1 Volume vs Pressure Loading

• Endurance: ↑ preload → eccentric LVH (Frank-Starling adaptation)
• Strength: ↑ afterload → concentric LVH
• Mixed sports: combined patterns
• Sex differences: females less LVH for same training

294.3.1.2 African American Athlete Cardiac Differences

• Earlier + more pronounced LVH
• More T-wave inversions in V1-V4 (normal variant)
• “Black athlete pattern” ECG
• Important to recognize to avoid false positives

294.3.1.3 COVID-19 Myocarditis Pathobiology

• SARS-CoV-2 ACE2 entry to cardiomyocytes
• Direct viral + immune-mediated injury
• Risk in athletes: 1-2% in early studies, less with later variants
• mRNA vaccine-associated rare (young males)

294.3.2 Recent Trials & Updates

294.3.2.1 LIVE-HCM (2023)

• Prospective study of HCM patients exercising
• No increase in adverse events with moderate exercise
• Changed 2024 ACC/AHA recommendations

294.3.2.2 2024 ACC/AHA Sports Cardiology Update

• More liberal for HCM, LQT, ARVC
• Individualized + shared decision-making
• ICD doesn’t automatically disqualify

294.3.2.3 MAGNIS (Magnetic Resonance Imaging Recovery from COVID Athletes)

• Serial CMR in college athletes post-COVID
• 1-2% myocarditis early; less with current strains
• Recovery favorable in most

294.3.2.4 Commotio Cordis Animal Models

• Vulnerable T-wave period 10-20 ms
• Frequency: 30-50 Hz impact most arrhythmogenic
• Prevention: chest protector (Pectibroil, in baseball)

294.3.2.5 Athletic Heart Reversibility (Detraining Studies)

• 6-12 weeks of detraining
• 50%+ reversion of LV dilation
• Diagnostic in distinguishing from HCM

294.3.3 High-Yield Specialist Points

294.3.3.1 Sports + Specific Cardiac Conditions

Mitral Valve Prolapse: - Mostly benign - Arrhythmic MVP rare cause of SCD - Bileaflet MVP + female + papillary muscle fibrosis on CMR ↑ risk - VT, FHX SCD → ICD consideration

Marfan + Athletes: - Aortic dilation contraindicates competitive sport - Aerobic non-competitive OK - Avoid isometric / contact sports - Beta-blocker + losartan

WPW: - Asymptomatic + young: risk stratify with EP study (shortest pre-excited RR) - High-risk pathway → ablation - Symptomatic + structural heart disease: ablation - Most can compete after ablation

Anomalous Coronary: - Restriction during evaluation - Surgical correction → return to play - Multidisciplinary

294.3.3.2 CHILD-CV Risk Assessment in Athletes

• AHA proposed for adolescents/young adults
• Annual physical includes CV screen
• Family history detailed

294.3.3.3 ICDs in Athletes

• Long-debated
• 2015 RIGHT-V registry: athletes with ICD often compete safely
• 2024 update: more permissive based on individual lesion + arrhythmia history

294.3.3.4 Hypoxic Training + Altitude

• Helpful for endurance
• Risk in patients with PH, sickle cell trait
• Pre-training screening

294.3.3.5 Anabolic Steroids + Cardiac

• LVH (concentric)
• HTN, MI, sudden death
• Reversible somewhat
• Avoid

294.3.3.6 Athlete with Cardiac Implant

• Pacemaker / ICD
• Lead position consideration in contact sports
• Defibrillation testing
• Programming for athletes (lower lower-rate, higher upper)

294.3.3.7 Exercise + Atrial Fibrillation

• Endurance athletes paradoxically higher AF
• “Athletic AF”
• May regress with reduced training
• Catheter ablation effective

294.3.3.8 Pediatric Sports + Cardiology

• AHA Standardized Athletic Pre-participation
• Recurrent syncope → workup
• Family history detailed
• Genetic counseling

294.3.4 Pearls

• Athletic heart: eccentric LVH (endurance) / concentric (strength); ECG variants common
• SCD young: HCM (US), anomalous coronary (Italy), ARVC, LQT, Brugada, WPW, myocarditis, commotio cordis
• SCD older: CAD primary
• 2024 ACC/AHA Sports Cardiology: more liberal; HCM + LIVE-HCM permit moderate exercise
• Italian model: ECG-inclusive screening ↓ SCD 90%
• Commotio cordis: AED + CPR life-saving (Damar Hamlin 2023)
• COVID-19 myocarditis: 3-6 mo restriction; CMR + serial monitoring

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