ECG measurements and prevalence of various ECG findings
| ECG variables | Controls | GOLD | Controls vs COPD | GOLD stage | ||
| n=32 | 2 (n=40) | 3 (n=30) | 4 (n=31) | p | p | |
| -axis (°) | 52 (21) | 67 (26) | 64 (41) | 69 (22) | <0.0001 | 0.72 |
| P in V1 (mm) | 0.6 (0.2) | 0.6 (0.4) | 0.5 (0.5) | 0.2 (0.7) | 0.02 | 0.009 |
| P in II, aVF, III (mm) | 1.3 (0.5) | 1.3 (0.6) | 1.3 (0.8) | 1.3 (0.8) | 0.92 | 0.94 |
| QRS duration (ms) | 91 (13) | 87 (16) | 88 (15) | 83 (12) | 0.09 | 0.46 |
| QRS-axis (°) | 34 (42) | 60 (27) | 75 (37) | 45 (55) | 0.0002 | 0.94 |
| V1 R/S | 0.2 (0.2) | 0.4 (0.6) | 0.5 (0.9) | 0.2 (0.2) | 0.98 | 0.38 |
| V2 R/S | 0.6 (0.4) | 0.8 (1.3) | 0.6 (0.9) | 0.4 (0.5) | 0.02 | 0.02 |
| V3 R/S | 2.0 (3.1) | 1.8 (2.3) | 1.3 (1.2) | 1.0 (1.6) | 0.02 | 0.02 |
| V4 R/S | 5.7 (6.4) | 4.4 (7.5) | 4.2 (6.2) | 2.8 (3.8) | 0.007 | 0.10 |
| V5 R/S | 10.2 (11.4) | 6.5 (7.4) | 6.2 (7.4) | 4.1 (5.0) | 0.02 | 0.02 |
| SL RVH (mm) | 4 (3) | 5 (3) | 6 (5) | 5 (4) | 0.07 | 0.50 |
| SL RVH p. (mm·ms) | 354 (251) | 415 (286) | 524 (479) | 451 (325) | 0.17 | 0.66 |
| SL LVH (mm) | 20 (6) | 20 (6) | 18 (6) | 14 (6) | 0.07 | 0.0003 |
| Cornell Index (mm) | 13 (6) | 12 (5) | 12 (5) | 15 (6) | 0.98 | 0.12 |
| Cornell p. (mm·ms) | 1243 (734) | 1053 (470) | 1070 (504) | 1234 (539) | 0.61 | 0.17 |
| R+S precordial leads | 81 (20) | 80 (18) | 77 (22) | 67 (19) | 0.13 | 0.01 |
| R+S frontal leads | 24 (8) | 24 (5) | 23 (7) | 20 (6) | 0.32 | 0.009 |
| Precordial/frontal amp | 3.5 (0.8) | 3.5 (0.9) | 3.6 (1.6) | 3.8 (1.8) | 0.47 | 0.96 |
| CCW n (%) | 18 (60) | 17 (43) | 12 (40) | 5 (16) | 0.02 | 0.03 |
| Clockwise n (%) | 3 (9) | 5 (13) | 7 (23) | 10 (32) | 0.15 | 0.11 |
| Prevalence of various ECG findings | ||||||
| Abnormal ECG | 8 (25%) | 34 (85%) | 20 (67%) | 29 (94%) | <0.0001 | 0.49 |
| HR >80 beats/min | 4 (13%) | 24 (60%) | 15 (50%) | 22 (71%) | <0.0001 | 0.44 |
| P-axis:<0°or>75° | 1 (3%) | 10 (25%) | 10 (34%) | 9 (29%) | 0.0014 | 0.65 |
| P-pulmonale | 0 (0%) | 4 (10%) | 2 (7%) | 2 (6%) | 0.18 | 0.57 |
| QRS <70 or>120 ms | 1 (3%) | 12 (30%) | 7 (23%) | 5 (16%) | 0.008 | 0.18 |
| QRS-axis −30° to 90° | 29 (84%) | 40 (100%) | 28 (93%) | 24 (77%) | 1.0000 | 0.001 |
| Left axis −31° to −90° | 3 (16%) | 0 (0%) | 0 (0%) | 5 (16%) | 0.40 | 0.004 |
| Right axis >90° | 0 (0%) | 0 (0%) | 2 (7%) | 2 (6%) | 1.0000 | 0.14 |
| Low voltage I–III | 1 (3%) | 0 (0%) | 1 (3%) | 1 (3%) | 0.57 | 0.31 |
| R/S in V1>1 | 0 (0%) | 1 (3%) | 2 (7%) | 3 (10%) | 0.34 | 0.20 |
| R/S in V5<1 | 0 (0%) | 3 (8%) | 3 (10%) | 1 (3%) | 0.19 | 0.57 |
| S1S2S3 pattern | 2 (7%) | 1 (3%) | 2 (8%) | 7 (23%) | 0.73 | 0.009 |
| RVH SL | 0 (0%) | 0 (0%) | 1 (3%) | 3 (10%) | 0.57 | 0.05 |
| RVH Scott et al11 | 1 (3%) | 2 (5%) | 3 (10%) | 2 (6%) | 0.68 | 0.75 |
| RVH Scott or SL11 16 | 0 (3%) | 3 (8%) | 4 (13 %) | 1 (4%) | 0.20 | 0.73 |
Values are mean (SD) of continuous variables.
Bold values are statistically significant. p Values refer to Kendall’s t- correlation for trend comparing GOLD stage II, III and IV for each variable and Wilcoxon/ Kruskal-Wallis Rank Sum Test comparing COPD and controls, with Chi square approximation.
amp, amplitudes; Cornell p, Cornell product; CCW, counter-clockwise; GOLD, Global Initiative for Chronic Obstructive Lung Disease; HR, heart rate; p, p value; SL RVH, Sokolow-Lyon right ventricular hypertrophy; SL RVH p, Sokolow-Lyon product; SL LVH, Sokolow-Lyon left ventricular hypertrophy.