ECG abnormalities found at the screening according to the Lausanne recommendations
| Total (N = 55)* | |
| P-wave, n (%) | |
| Left atrial enlargement: negative portion of the P-wave in lead V1 ⩾0.1 mV in depth and ⩾0.04 s in duration | 1 (2) |
| Right atrial enlargement: peaked P-wave in leads II and III or V1 ⩾0.25 mV in amplitude | – |
| QRS-complex, n (%) | |
| Frontal-plane QRS axis deviation: right ⩾ +120° or left −30° to −90° | 4 (7) |
| Increased voltage: amplitude of R or S-wave in a standard lead ⩾2 mV, S-wave in lead V1 or V2 ⩾3 mV, or R-wave in lead V5 or V6 ⩾3 mV | 13 (24)† |
| Abnormal Q-waves ⩾0.04 s in duration or ⩾25% of the height of the ensuing R-wave, or QS pattern in ⩾2 leads | 1 (2) |
| Right or left bundle-branch block with QRS duration ⩾0.12 s | 4 (7) |
| R or R′-wave in lead V1 ⩾0.5 mV in amplitude and R : S ratio ⩾1 | 5 (9) |
| ST-segment, T-waves and QT-interval, n (%) | |
| ST-segment depression or T-wave flattening or inversion in ⩾2 leads | 12 (22) |
| Prolongation of heart rate corrected QT-interval ⩾0.44 s in men and ⩾0.46 s in women | 2 (4) |
| Rhythm and conduction abnormalities | |
| Premature ventricular beats or more severe ventricular arrhythmia | 2 (4) |
| Supraventricular tachycardia, atrial flutter, or atrial fibrillation | – |
| Ventricular pre-excitation: short PR interval (⩽0.12 s) with or without delta wave | 2 (4) |
| Sinus bradycardia with resting heart rate ⩽40 beats/min | 3 (5) |
| First-degree (PR ⩾0.21 s, not shortening with hyperventilation), second-degree or third-degree atrioventricular block | 3 (5) |
| Other | 3 (5) |
*A total of 36 athletes had an abnormal electrocardiogram (ECG). Together, these ECG showed 55 abnormalities. †In six of these 13 ECG this was the only abnormality found at the screening (including history and physical examination).