22. Sports Cardiology and International Criteria for Athlete ECG
Physiological adaptation to sustained athletic training ("Athlete's Heart") produces profound structural and electrical remodeling that must be accurately distinguished from pathological cardiomyopathy.
1. International Consensus Criteria for Electrocardiographic Interpretation in Athletes
| Normal Training-Related Findings (No Further Workup Required) | Borderline Findings (Require Investigation if $\ge 2$ Present) | Abnormal ECG Findings (Mandate Comprehensive Cardiovascular Workup) |
|---|---|---|
| 1. Increased QRS voltage for LVH (isolated Sokolow-Lyon criteria). | 1. Left Axis Deviation ($-30^\circ \text{ to } -90^\circ$). | 1. T-Wave Inversions: $\ge 1\text{ mm}$ deep in $\ge 2$ contiguous leads (excluding $V_1-V_4$ in Black athletes and $V_1-V_3$ in $<16$ yr). |
| 2. Incomplete Right Bundle Branch Block (IRBBB). | 2. Right Axis Deviation ($>+120^\circ$). | 2. ST-Segment Depression: $\ge 0.5\text{ mm}$ in $\ge 2$ contiguous leads. |
| 3. Early Repolarization (concave ST elevation, J-waves). | 3. Left Atrial Enlargement. | 3. Pathological Q Waves: Depth $>3\text{ mm}$ or width $\ge 40\text{ ms}$ in $\ge 2$ leads. |
| 4. Sinus Bradycardia (resting HR $\ge 30\text{ bpm}$) & Sinus Arrhythmia. | 4. Right Atrial Enlargement. | 4. Complete Left Bundle Branch Block (LBBB). |
| 5. First-Degree AV Block & Mobitz I Wenckebach during rest. | 5. Complete Right Bundle Branch Block (RBBB). | 5. QRS Duration $\ge 140\text{ ms}$ (non-specific IVCD). |
| 6. Upward concave ST elevation with T-wave inversion in $V_1-V_4$ in Black Athletes. | 6. Pre-Excitation (delta wave + short PR). | |
| 7. Prolonged $QTc \ge 470\text{ ms}$ (males) / $\ge 480\text{ ms}$ (females). | ||
| 8. Type 1 Brugada Pattern & Epsilon Waves. | ||
| 9. Ventricular Ectopy: $\ge 2$ PVCs per 10-second tracing. |
2. Multimodality Evaluation of the Abnormal Athlete's ECG
- Transthoracic Echocardiography & CMR: Differentiates physiological eccentric LV cavity enlargement ($LVEDD > 55-60\text{ mm}$ with normal diastolic filling and zero LGE) from early Dilated or Hypertrophic Cardiomyopathy.