Table 2. Abnormal Electrocardiographic (ECG) Findings.
| Abnormal ECG Classification | No. (%) | P Value | ||
|---|---|---|---|---|
| Total Athletes (n = 519) | Racial/Ethnic Subgroups | |||
| African American (n = 409) | White (n = 96) | |||
| Seattle criteria | 131 (25.2) | 103 (25.2) | 23 (24.0) | .90 |
| Refined criteria | 108 (20.8) | 87 (21.2) | 16 (16.6) | .33 |
| International recommendations | 81 (15.6) | 65 (15.8) | 11 (11.5) | .34 |
| Abnormal ECG findings | ||||
| Short QT Interval (QTc <320 ms) | 0 | 0 | 0 | .99 |
| Long QT Interval (QTc >470 ms) | 25 (4.8) | 20 (4.9) | 4 (4.2) | .98 |
| Left bundle branch block | 1 (0.2) | 1 (0.2) | 0 | .99 |
| Intraventricular conduction delaya | 5 (1.0) | 4 (1.0) | 0 | .74 |
| Q wavesb | 7 (1.4) | 4 (1.0) | 2 (2.1) | .32 |
| ST-segment depressionc | 9 (1.7) | 9 (2.2) | 0 | .22 |
| Abnormal T-wave inversiond | 32 (6.2) | 27 (6.6) | 3 (3.1) | .24 |
| Ventricular preexcitatione | 1 (0.2) | 1 (0.2) | 0 | .99 |
| Frequent premature ventricular contraction (>2) | 2 (0.4) | 2 (0.5) | 0 | .99 |
| ≥2 Borderline findings | 29 (5.6) | 22 (5.4) | 6 (6.3) | .91 |
| Borderline ECG findingsf | ||||
| Left atrial enlargement | 69 (13.3) | 53 (13.0) | 13 (13.5) | .87 |
| Right atrial enlargement | 46 (8.9) | 40 (9.8) | 6 (6.3) | .33 |
| QRS axis deviation | 21 (4.0) | 15 (3.7) | 6 (6.3) | .26 |
| Right bundle branch block | 25 (4.8) | 20 (4.9) | 4 (4.2) | .99 |
a
Intraventricular conduction delay is defined as any QRS duration >140 milliseconds.
b
Q waves are defined as 40 milliseconds or more or 25% or greater of height of ensuing R wave.
c
ST-segment depression is defined as 0.5 mm or greater in 2 or more leads.
d
Abnormal T-wave inversion is defined as 1 mm or greater in 2 or more leads (excluding III, aVR,V1, and T-wave inversion in V1-V4 in African American athletes when preceded by J point and/or ST elevation).
e
Ventricular preexcitation is defined as PR<120 milliseconds with delta wave and widened QRS.
f
Borderline ECG findings, when present in isolation, are considered unlikely to represent cardiac pathology in athletes, but 2 or more borderline findings are classified as abnormal.