Table 1.
Characteristics of the Study Group According to Pre‐Implantation QRS Area
| All | QRSarea ≥102 μVs | QRSarea <102 μVs | P Value | |
|---|---|---|---|---|
| N | 380 | 197 | 183 | |
| Age, y | 72±12.4 | 72.2±12.9 | 71.9±11.7 | 0.832 |
| Sex (male), n (%) | 261 (68.68) | 119 (60.41) | 142 (77.6) | <0.001 |
| NYHA class, n (%) | ||||
| I | 26 (7.34) | 17 (9.34) | 9 (5.23) | 0.190 |
| II | 87 (24.58) | 46 (25.27) | 41 (23.84) | |
| III | 225 (63.56) | 114 (62.64) | 111 (64.53) | |
| IV | 16 (4.52) | 5 (2.75) | 11 (6.4) | |
| Cause, n (%) | ||||
| Ischemic | 182 (47.89) | 74 (37.56) | 108 (59.02) | <0.001 |
| Nonischemic | 198 (52.11) | 123 (62.44) | 75 (40.98) | |
| Comorbidities, n (%) | ||||
| Diabetes mellitus | 89 (23.42) | 41 (20.81) | 48 (26.23) | 0.213 |
| Hypertension | 106 (27.89) | 57 (28.93) | 49 (26.78) | 0.639 |
| CABG | 64 (16.84) | 23 (11.68) | 41 (22.4) | 0.005 |
| Device type, n (%) | ||||
| CRT‐D | 209 (55.15) | 94 (47.96) | 115 (62.84) | 0.004 |
| CRT‐P | 170 (44.85) | 102 (52.04) | 68 (37.16) | |
| Upgrades, n (%) | ||||
| Pacemaker to CRT‐D | 39 (47.56) | 23 (43.40) | 16 (55.17) | 0.307 |
| Pacemaker to CRT‐P | 43 (52.44) | 30 (56.60) | 13 (44.83) | |
| CRT‐D indicationa | ||||
| Primary prevention | 166 (79.4) | 76 (80.9) | 90 (78.3) | 0.645 |
| Secondary prevention | 43 (20.6) | 18 (19.1) | 25 (21.7) | |
| LVEF, % | 25.8±9.9 | 25.5±9.7 | 26.0±10.3 | 0.633 |
| Medication, n (%) | ||||
| ACEI/ARA | 337 (89.63) | 173 (88.72) | 164 (90.61) | 0.548 |
| β‐Blocker | 277 (73.67) | 140 (71.79) | 137 (75.69) | 0.391 |
| MRA | 167 (44.41) | 80 (41.03) | 87 (48.07) | 0.170 |
| ECG variables | ||||
| Sinus rhythm, n (%) | 269 (70.79) | 152 (77.16) | 117 (63.93) | 0.005 |
| AF/flutter, n (%) | 111 (29.21) | 45 (22.84) | 66 (36.07) | |
| PR interval, ms | 192.5±54.7 | 181.6±39.8 | 207.5±67.5 | <0.001 |
| QRSd, ms | 153.5±22.7 | 163.9±20.4 | 142.2±19.5 | <0.001 |
| QRS <150 ms, n (%) | 169 (44.47) | 45 (22.84) | 124 (67.76) | <0.001 |
| LBBB, n (%) | 239 (62.89) | 151 (76.65) | 88 (48.09) | <0.001 |
| RBBB, n (%) | 33 (8.68) | 1 (0.51) | 32 (17.49) | <0.001 |
| NICD, n (%) | 59 (15.53) | 5 (2.54) | 54 (29.51) | <0.001 |
| RV‐paced, n (%) | 49 (12.89) | 40 (20.30) | 9 (4.92) | <0.001 |
| Vectorcardiography variable | ||||
| QRSarea, μVs | 113.4±56.5 | 156.9±41.7 | 66.6±22.7 | <0.001 |
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; MRA, mineralocorticoid receptor antagonist; LVEF, left ventricular ejection fraction; NICD, nonspecific conduction delay; NYHA, New York Heart Association; QRSarea, QRS area; QRSd, QRS duration; RBBB, right bundle branch block; RV, right ventricular.
a
Expressed as a percentage of CRT‐D devices.