Table 1 Definitions of electrocardiographic and echocardiographic parameters used in this study
Variables | Definitions |
|---|---|
Epsilon wave (major depolarization criterion) | Distinct waves of small amplitude that occupy the ST segment in right precordial leads (V1-V3) and are distinct from the QRS complex |
Terminal activation duration (minor depolarization criterion) | Longest value in V1 through V3 from the nadir of the S wave to the end of all depolarization |
T wave inversion | Any T wave negativity |
Inferior leads T wave inversion | Inverted T waves in 2 out of 3 inferior leads (II, III, and aVF) |
Major repolarization criteria | Inverted T waves in right precordial leads (V1, V2, and V3) or beyond in individuals >14 years of age (in the absence of complete right bundle branch block) |
Minor repolarization criteria | - Inverted T waves in leads V1 and V2 in individuals >14 years of age (in the absence of complete right bundle branch block) or in V4, V5, or V6 |
- Inverted T waves in leads V1, V2, V3, and V4 in individuals >14 years of age in the presence of complete right bundle branch block | |
Complete right bundle branch block | QRSd ≥120 ms and: |
A1: R’ or r’ in V1 or V2 | |
A2: S duration > R duration in I and V6 | |
A3: S duration >40 ms in I and V6 | |
A4: R peak time >50 ms in V1 or V2 | |
a: A1 + A2 | |
b: A1+ A3 | |
c: A4+ (A2 or A3) | |
Incomplete right bundle branch block | QRS <120 ms and R peak time in V1 or V2 > 50 ms |
QRS notching | Additional deflections/notches at the beginning of the QRS, on top of the R-wave, or in the nadir of the S-wave in the absence of bundle branch block |
Left ventricular involvement | Echocardiographic documentation of LV wall motion abnormalities or a reduced ejection fraction (<50%) in the absence of other causes |
Right ventricular regional wall motion abnormalities | Echocardiographic documentation of regional right ventricular akinesia/dyskinesia |