Skip to content

Case 002: Syncope in a Young Athlete

Presentation

Chief Complaint: 15-year-old male collapsed during basketball practice

History: - Playing basketball when suddenly collapsed without warning - Witnessed by coach: "He just dropped" - Brief LOC (~30 seconds), confused for 1-2 minutes after - No prodrome (no lightheadedness, vision changes, nausea) - No seizure activity witnessed - Has had "near blackouts" twice before during exertion over past year - Denies chest pain, palpitations - No prior medical history

Family History: - Father's brother died suddenly at age 32 (cause unknown) - No known heart disease in parents

Physical Examination: - Alert, oriented, appears well - HR: 72, BP: 118/70, SpO2: 99% - Cardiac: Regular rhythm, Grade 2/6 systolic ejection murmur at LLSB, increases with standing - No marfanoid features - Normal peripheral pulses

Question 1

What are the red flags in this presentation that warrant urgent cardiac evaluation?

Answer **Major Red Flags Present:** 1. **Exertional syncope** - Occurred during athletic activity 2. **No prodrome** - Sudden collapse without warning symptoms 3. **Family history of sudden death** - Uncle died at 32 (suspicious for inherited condition) 4. **Murmur that increases with standing** - Concerning for HCM (LVOT obstruction increases with decreased preload) 5. **Prior exertional near-syncope** - Pattern of exercise-related events This presentation is HIGH RISK for sudden cardiac death and requires comprehensive evaluation before any return to activity.

Workup

ECG: - Sinus rhythm, 68 bpm - LVH voltage criteria (SV1 + RV6 = 42 mm) - Deep T-wave inversions in V4-V6 - Narrow Q waves in lateral leads

What does this ECG suggest?

Answer **This ECG is highly concerning for Hypertrophic Cardiomyopathy (HCM):** - LVH voltage criteria - Deep T-wave inversions (repolarization abnormalities) - Narrow Q waves in lateral leads (septal hypertrophy) This pattern, combined with the history and exam, makes HCM the leading diagnosis.

Echocardiogram

  • Asymmetric septal hypertrophy: IVS 22 mm (Z-score +8)
  • Posterior wall: 10 mm
  • Systolic anterior motion (SAM) of mitral valve
  • LVOT gradient: 45 mmHg at rest, 85 mmHg with Valsalva
  • Normal LV systolic function
  • Mild mitral regurgitation

Question 2

What is the diagnosis and what are the next steps in management?

Answer **Diagnosis:** Hypertrophic Obstructive Cardiomyopathy (HOCM) **Immediate Management:** 1. **No sports participation** - Restriction from all competitive athletics 2. **Medications:** Start beta-blocker (propranolol or nadolol) 3. **Risk stratification for ICD:** - Prior syncope (likely arrhythmic given exertional nature) ✓ - Family history of SCD ✓ - Massive LVH (Z-score +8) ✓ - Patient has multiple risk factors → ICD evaluation **Further Workup:** 1. Holter monitor (assess for NSVT) 2. Exercise stress test (assess symptoms, BP response, arrhythmias) 3. Cardiac MRI (assess fibrosis, confirm anatomy) 4. Genetic testing 5. Family screening (ECG + echo for first-degree relatives)

Question 3

What genetic counseling and family screening should be performed?

Answer **Genetic Testing in Proband:** - Comprehensive HCM panel (sarcomere genes) - Most common: MYH7, MYBPC3 - ~60% yield in familial HCM **Family Screening:** 1. **First-degree relatives:** - ECG + Echocardiogram - If genetic mutation identified → cascade testing 2. **Screening intervals for at-risk relatives:** - Ages 12-18: Every 1-2 years during growth - Adults: Every 3-5 years - Earlier/more frequent if: - Family history of early-onset disease - Competitive athlete - Symptoms develop 3. **Father should be screened** given family history of uncle's sudden death

Risk Stratification

Major Risk Factors for SCD in Pediatric HCM: - ✓ Massive LVH (most important in pediatrics) - ✓ Prior syncope (especially exertional) - ✓ Family history of SCD - Pending: NSVT on Holter - Pending: Abnormal BP response to exercise

Question 4

This patient has multiple SCD risk factors. What is the recommendation regarding ICD?

Answer **ICD Recommendation:** Given: - Massive LVH (Z-score +8) - strongest pediatric risk factor - Exertional syncope (likely arrhythmic) - Family history of SCD **ICD implantation is indicated for primary prevention.** The combination of extreme LVH + exertional syncope + family history puts this patient at HIGH risk. ICD should be discussed with family. **Device considerations in adolescents:** - Transvenous ICD vs subcutaneous ICD (S-ICD) - S-ICD avoids lead complications in young patients - Device counseling important (psychological impact)

Follow-up Plan

  1. Start metoprolol - titrate to symptom control and resting HR ~60
  2. Holter monitor - completed, showed rare PVCs, no NSVT
  3. Exercise test - deferred given syncope; will perform after beta-blockade
  4. Cardiac MRI - confirmed diagnosis, no significant fibrosis
  5. ICD counseling - family elected to proceed with S-ICD
  6. Genetic testing - MYH7 mutation identified
  7. Family screening - Father found to have mild HCM (18mm septum)

Question 5

Can this patient ever return to sports?

Answer **Current Guideline Approach (Shared Decision-Making):** 2015+ guidelines moved from absolute disqualification to shared decision-making. **Requirements for consideration:** 1. Comprehensive evaluation completed 2. Treatment optimized (medications, ICD if indicated) 3. Understanding of risks discussed with patient/family 4. Regular follow-up ensured **Practical Reality:** - Most physicians still recommend against high-intensity competitive sports - Lower-intensity recreational activity may be considered - Decision involves patient autonomy, medical risk assessment - Document thorough discussion **For this patient:** - Given exertional syncope + multiple risk factors, most would advise against basketball - After ICD placement and beta-blockade, lower-intensity activities could be discussed - Swimming generally avoided (difficult to rescue if arrest occurs)

Board Pearls

Pearl

Extreme LVH is the most important SCD risk factor in PEDIATRIC HCM

Pearl

Murmur that increases with Valsalva or standing = think HOCM (decreased preload → increased obstruction)

Pearl

Sports participation in HCM now involves shared decision-making rather than automatic disqualification

Pearl

Exertional syncope + family history of SCD + HCM = ICD evaluation

Learning Points

  1. Exertional syncope is a red flag - Always requires cardiac evaluation
  2. Family history matters - Sudden death in relatives raises concern for inherited conditions
  3. HCM exam finding - Murmur increases with standing/Valsalva (opposite of most murmurs)
  4. Pediatric vs adult risk - Extreme LVH is more predictive of SCD in children than in adults
  5. Family screening - Essential after any HCM diagnosis

References

  • 2024 AHA/ACC HCM Guidelines
  • 2015 AHA/ACC Sports Eligibility Recommendations