Table 1

Electrocardiographic parameters used to define various ECG abnormalities in the European Society of Cardiology recommendations, Seattle Criteria and Refined Criteria

ECG abnormalityEuropean Society of Cardiology (ESC) recommendationsSeattle CriteriaRefined Criteria
Left atrial enlargementNegative portion of the P-wave in lead V1 ≥0.1 mV in depth and ≥40 ms in durationProlonged P-wave duration of >120 ms in leads I or II with negative portion of the P-wave ≥0.1 mV in depth and ≥40 ms in duration in lead V1As ESC
Right atrial enlargementP-wave amplitude ≥2.5 mm in leads II, III or aVFAs ESCAs ESC
Left QRS-axis deviation−30° to −90°As ESCAs ESC
Right QRS-axis deviation>115°>120°As ESC
RV hypertrophySum of R-wave in V1 and S-wave in V5 or V6 ≥1.05 mVSum of R-wave in V1 and S-wave in V5>1.05 mV and right axis deviation >120OAs ESC
Corrected QT interval>440 ms (men) and >460 ms (women)>470 ms (men) and 480 ms (women)As Seattle
Complete left bundle branch blockQRS ≥120 ms predominantly negative QRS complex in lead V1 (QS or rS), and upright monophasic R-wave in leads I and V6As ESCAs ESC
Complete right bundle branch blockRSR pattern in anterior precordial leads with QRS duration ≥120 msNot relevantAs ESC
Intraventricular conduction delayAny QRS duration >120 ms including RBBB and LBBBAny QRS duration ≥140 ms or complete LBBBAs ESC
Pathological Q-wave>0.4 mV deep in any lead except III, aVR>0.3 mV deep and/or >40 ms duration in ≥2 leads except III and aVR≥40 ms in duration or ≥25% of the height of the ensuing R-wave
Significant T-wave inversion≥2 mm in ≥2 adjacent leads (deep)or ‘minor’ in ≥2 leads>1 mm in depth in two or more leads V2−6, II and aVF or I and aVL (excludes III, aVR and V1)As Seattle
ST-segment depression≥0.5 mm deep in ≥2 leadsAs ESCAs ESC
Ventricular pre-excitationPR interval <120 ms with or without delta wavePR interval <120 ms with delta waveAs Seattle

  • LBBB, left bundle branch block; mm, millimetres; ms, milliseconds; RBBB, right bundle branch block.