Table 1

International consensus standards for ECG interpretation in athletes: definitions of ECG criteria

Abnormal ECG findings in athletes
These ECG findings are unrelated to regular training or expected physiological adaptation to exercise, may suggest the presence of pathological cardiovascular disease and require further diagnostic investigation.
ECG abnormality Definition
T wave inversion≥1 mm in depth in two or more contiguous leads; excludes leads aVR, III and V1
  • Anterior

  • V2-V4

excludes: black athletes with J-point elevation and convex ST segment elevation followed by TWI in V2-V4; athletes < age 16 with TWI in V1-V3; and biphasic T waves in only V3
  • Lateral

  • I and aVL, V5 and/or V6 (only one lead of TWI required in V5 or V6)

  • Inferolateral

  • II and aVF, V5-V6, I and aVL

  • Inferior

  • II and aVF

ST segment depression≥0.5 mm in depth in two or more contiguous leads
Pathological Q wavesQ/R ratio ≥0.25 or ≥40 ms in duration in two or more leads (excluding III and aVR)
Complete left bundle branch blockQRS ≥120 ms, predominantly negative QRS complex in lead V1 (QS or rS) and upright notched or slurred R wave in leads I and V6
Profound non-specific intraventricular conduction delayAny QRS duration ≥140 ms
Epsilon waveDistinct low amplitude signal (small positive deflection or notch) between the end of the QRS complex and onset of the T wave in leads V1-V3
Ventricular pre-excitationPR interval <120 ms with a delta wave (slurred upstroke in the QRS complex) and wide QRS (≥120 ms)
Prolonged QT interval*QTc ≥470 ms (male)
QTc ≥480 ms (female)
QTc ≥500 ms (marked QT prolongation)
Brugada type 1 patternCoved pattern: initial ST elevation ≥2 mm (high take-off) with downsloping ST segment elevation followed by a negative symmetric T wave in ≥1 leads in V1-V3
Profound sinus bradycardia<30 beats per minute or sinus pauses ≥3 s
Profound 1° atrioventricular block≥400 ms
Mobitz type II 2° atrioventricular blockIntermittently non-conducted P waves with a fixed PR interval
3° atrioventricular blockComplete heart block
Atrial tachyarrhythmiasSupraventricular tachycardia, atrial fibrillation, atrial flutter
Premature ventricular contractions≥2 premature ventricular contractions per 10 s tracing
Ventricular arrhythmiasCouplets, triplets and non-sustained ventricular tachycardia
Borderline ECG findings in athletes
These ECG findings in isolation likely do not represent pathological cardiovascular disease in athletes, but the presence of two or more borderline findings may warrant additional investigation until further data become available.
ECG abnormality Definition
Left axis deviation−30° to −90°
Left atrial enlargementProlonged P wave duration of >120 ms in leads I or II with negative portion of the P wave ≥1 mm in depth and ≥40 ms in duration in lead V1
Right axis deviation>120°
Right atrial enlargementP wave ≥2.5 mm in II, III or aVF
Complete right bundle branch blockrSR′ pattern in lead V1 and an S wave wider than R wave in lead V6 with QRS duration ≥120 ms
Normal ECG findings in athletes
These training-related ECG alterations are physiological adaptations to regular exercise, considered normal variants in athletes and do not require further evaluation in asymptomatic athletes with no significant family history.
Normal ECG finding Definition
Increased QRS voltageIsolated QRS voltage criteria for left (SV1 + RV5 or RV6 >3.5 mV) or right ventricular hypertrophy (RV1 + SV5 or SV6 >1.1 mV)
Incomplete right bundle branch blockrSR′ pattern in lead V1 and a qRS pattern in lead V6 with QRS duration <120 ms
Early repolarisationJ point elevation, ST elevation, J waves or terminal QRS slurring in the inferior and/or lateral leads
Black athlete repolarisation variantJ-point elevation and convex (‘domed’) ST segment elevation followed by T wave inversion in leads V1-V4 in black athletes
Juvenile T wave patternT wave inversion V1-V3 in athletes less than age 16
Sinus bradycardia≥30 bpm
Sinus arrhythmiaHeart rate variation with respiration: rate increases during inspiration and decreases during expiration
Ectopic atrial rhythmP waves are a different morphology compared with the sinus P wave, such as negative P waves in the inferior leads (‘low atrial rhythm’)
Junctional escape rhythmQRS rate is faster than the resting P wave or sinus rate and typically less than 100 beats/min with narrow QRS complex unless the baseline QRS is conducted with aberrancy
1° atrioventricular blockPR interval 200–400 ms
Mobitz type I (Wenckebach) 2° atrioventricular blockPR interval progressively lengthens until there is a non-conducted P wave with no QRS complex; the first PR interval after the dropped beat is shorter than the last conducted PR interval
  • *The QT interval corrected for heart rate is ideally measured using Bazett’s formula with heart rates between 60–90 bpm; preferably performed manually in lead II or V5 using the teach-the-tangent method112 to avoid inclusion of a U wave (please see text for more details). Consider repeating the ECG after mild aerobic activity for a heart rate <50 bpm, or repeating the ECG after a longer resting period for a heart rate >100 bpm, if the QTc value is borderline or abnormal.