Table 2.
Electrocardiographic and Echocardiographic Parameters by QRS-T Angle Tertile
| Parameter | Tertile 1 | Tertile 2 | Tertile 3 | P-value |
|---|---|---|---|---|
| 0–26° (N=124) | 27–75° (N=125) | 76–179° (N=127) | ||
| QRS-T Angle (°) | 13±7 | 47 ±14 | 123±31 | |
|
| ||||
| Electrocardiographic parameters | ||||
| • Heart rate, bpm | 70±14 | 74±15 | 73±17 | 0.20 |
| • PR interval, ms | 167±29 | 174±40 | 183±42 | 0.01 |
| • QRS interval, ms | 86±11 | 94±19 | 109±26 | <0.001 |
| • Left bundle branch block, n (%) | 0 (0) | 2 (2) | 11 (9) | <0.001 |
| • Right bundle branch block, n (%) | 1 (1) | 6 (5) | 17 (13) | <0.001 |
| • Intraventricular conduction delay, n (%) | 1 (1) | 8 (6) | 12 (9) | 0.005 |
| • QT interval, ms | 417±44 | 411±44 | 425±50 | 0.053 |
| • QTc interval, ms | 447±37 | 450±32 | 462±40 | 0.058 |
| • QRS axis, degrees* | 31 (11,49) | 6 (−16,42) | −15 (−48,41) | <0.001† |
| • T-wave axis, degrees* | 34 (18,49) | 37 (16,56) | 80 (57,110) | <0.001† |
| • T-wave inversion, n (%) | 18 (15) | 31 (26) | 81 (68) | <0.001 |
| Echocardiographic parameters | ||||
| • LV ejection fraction, % | 62±6 | 61±6 | 61±7 | 0.32 |
| • LV end-systolic volume index, ml/m2 | 16±6 | 15±5 | 18±9 | 0.029 |
| • LV end-diastolic volume index, ml/m2 | 41±11 | 39±8 | 45±15 | 0.008 |
| • Left atrial volume index, ml/m2 | 31±12 | 33±14 | 37±16 | 0.012 |
| • LV mass index, g/m2 | 90±24 | 98±29 | 119±44 | <0.001 |
| • LV diastolic function, n (%) | 0.003 | |||
| ○ Normal | 17(14) | 9(7) | 3(2) | |
| ○ Grade 1 (impaired relaxation) | 7(6) | 16(13) | 17(14) | |
| ○ Grade 2 (pseudonormal) | 59(58) | 49(39) | 45(35) | |
| ○ Grade 3 (restrictive) | 36(29) | 38(30) | 49(39) | |
| ○ Indeterminate | 5(4) | 13(10) | 13(10) | |
| • E/A ratio | 1.3±0.6 | 1.3±0.7 | 1.5±0.9 | 0.13 |
| • E deceleration time, ms | 222±47 | 241±76 | 227±71 | 0.06 |
| • Isovolumic relaxation time, ms | 82±18 | 85±20 | 94±27 | <0.001 |
| • Tissue Doppler e’ velocity, cm/s | 7.9±2.5 | 7.1±2.6 | 6.4±2.9 | <0.001 |
| • Tissue Doppler s’ velocity, cm/s | 8.0±2.1 | 7.3±1.9 | 6.7±2.0 | <0.001 |
| • E/e’ ratio | 14.4±5.4 | 16.3±8.7 | 19.9±11.5 | <0.001 |
| • RV basal diameter, cm/m2 | 1.9±0.4 | 1.9±0.4 | 2.1±0.4 | 0.002 |
| • RV length, cm/m2 | 3.9±0.6 | 3.9±0.6 | 4.2±0.7 | <0.001 |
| • RV end-diastolic area index, cm2/m2 | 13.1±3.0 | 13.7±3.8 | 14.8±4.5 | 0.002 |
| • RV end-systolic area index, cm2/m2 | 7.4±2.1 | 7.9±2.8 | 8.8±3.3 | <0.001 |
| • RV wall thickness, cm/m2 | 0.24±0.05 | 0.26±0.06 | 0.28±0.07 | <0.001 |
| • RV fractional area change | 0.44±0.06 | 0.43±0.07 | 0.41±0.08 | 0.011 |
| • Right atrial area, cm2/m2 | 9.8±3.3 | 10.7±5.3 | 12.0±5.1 | 0.002 |
| • TAPSE, cm | 1.10±0.32 | 0.98±0.30 | 0.94±0.31 | <0.001 |
| • PA systolic pressure, mmHg | 41±16 | 47±18 | 49±18 | 0.011 |
*
Median (25th, 75th percentile);
†
Kruskal-Wallis test; LV, left ventricular; RV, right ventricular; TAPSE, tricuspid annular plane systolic excursion; PA, pulmonary artery