Table 5.
Characteristics of the Study Group According to Post‐Implantation Change in QRS Area
| QRSarea Reduction ≥45 μVs | QRSarea Reduction <45 μVs | P Value | |
|---|---|---|---|
| N | 177 | 203 | |
| Age, y | 72.1±13.1 | 72±11.7 | 0.979 |
| Sex (male), n (%) | 103 (58.19) | 158 (77.83) | <0.001 |
| NYHA class, n (%) | |||
| I | 14 (8.48) | 12 (6.35) | 0.322 |
| II | 36 (21.82) | 51 (26.98) | |
| III | 110 (66.67) | 115 (60.85) | |
| IV | 5 (3.03) | 11 (5.82) | |
| Cause, n (%) | |||
| Ischemic | 67 (37.85) | 115 (56.65) | <0.001 |
| Nonischemic | 110 (62.15) | 88 (43.35) | |
| Comorbidities, n (%) | |||
| Diabetes mellitus | 44 (24.86) | 45 (22.17) | 0.537 |
| Hypertension | 50 (28.25) | 56 (27.59) | 0.886 |
| CABG | 17 (9.6) | 47 (23.15) | <0.001 |
| Device type, n (%) | |||
| CRT‐D | 90 (51.14) | 119 (58.62) | 0.144 |
| CRT‐P | 86 (48.86) | 84 (41.38) | |
| Upgrades, n (%) | |||
| Pacemaker to CRT‐D | 14 (35) | 25 (59.52) | 0.026 |
| Pacemaker to CRT‐P | 26 (65) | 17 (40.48) | |
| LVEF | 25.3±9.1 | 26.2±10.7 | 0.429 |
| Medication, n (%) | |||
| ACEI/ARA | 154 (88) | 183 (91.04) | 0.334 |
| β‐Blocker | 125 (71.43) | 152 (75.62) | 0.357 |
| MRA | 82 (46.86) | 85 (42.29) | 0.374 |
| ECG variables | |||
| Sinus rhythm, n (%) | 139 (78.53) | 130 (64.04) | 0.002 |
| AF/flutter, n (%) | 38 (21.47) | 73 (35.96) | |
| PR interval, ms | 178.3±34.5 | 208.8±67.6 | <0.001 |
| QRSd, ms | 162.1±20.6 | 145.9±21.8 | <0.001 |
| LBBB, n (%) | 134 (75.71) | 105 (51.72) | <0.001 |
| RBBB, n (%) | 2 (1.13) | 31 (15.27) | <0.001 |
| NICD, n (%) | 10 (5.65) | 49 (24.14) | <0.001 |
| RV‐paced, n (%) | 31 (17.51) | 18 (8.87) | 0.012 |
| Vectorcardiography variable | |||
| QRSarea, μVs | 153.9±47.5 | 78.1±36.3 | <0.001 |
| Circumferential lead positions | |||
| Anterior | 6 (3.39) | 8 (3.94) | 0.498 |
| Anterolateral | 28 (15.8) | 37 (18.2) | |
| Lateral | 73 (41.2) | 86 (42.3) | |
| Posterolateral | 24 (13.6) | 16 (9.03) | |
| Posterior | 46 (26.0) | 56 (27.6) | |
| Longitudinal lead positions | |||
| Basal | 19 (10.7) | 12 (5.91) | 0.249 |
| Mid | 99 (55.9) | 121 (59.6) | |
| Apical | 59 (33.3) | 70 (34.5) | |
ACEI indicates angiotensin receptor converting enzyme inhibitor; AF, atrial fibrillation; ARA, angiotensin receptor antagonist; CABG, coronary artery bypass graft; CRT‐D, cardiac resynchronization therapy with defibrillation; CRT‐P, cardiac resynchronization therapy‐pacing; LBBB, left bundle branch block; LVEF, left ventricular ejection fraction; MRA, mineralocorticoid receptor antagonist; NICD, nonspecific intraventricular conduction delay; NYHA, New York Heart Association; QRSarea, QRS area; QRSd, QRS duration; RBBB, right bundle branch block; RV, right ventricular.