Table 2. Distribution of QRS Duration and Morphology in Primary Cohort
CharacteristicsBlackWhiteP Valuea
Overall (N=932)Male (N=542)Female (N=390)Overall (N=1531)Male (N=1073)Female (N=458)
QRS interval, ms
Median (Q1, Q3)98.0 (88.0, 119.5)100.0 (91.0, 120.0)94.0 (86.0, 118.0)111.0 (97.0, 139.0)111.0 (98.0, 139.0)107.5 (92.0, 140.0)<0.001
QRS morphology (%)
LBBB115 (12.3)50 (9.2)65 (16.7)319 (20.8)177 (16.5)142 (31.0)0.012
RBBB14 (1.5)13 (2.4)1 (0.3)48 (3.1)42 (3.9)6 (1.3)0.002
IVCD128 (13.7)94 (17.3)34 (8.7)284 (18.5)231 (21.5)53 (11.6)<0.001
QRS category, ms (%)<0.001
<120699 (75.0)403 (74.4)296 (75.9)906 (59.2)644 (60.0)262 (57.2)
120 to 149142 (15.2)83 (15.3)59 (15.1)370 (24.2)253 (23.6)117 (25.6)
≥15091 (9.8)56 (10.3)35 (9.0)255 (16.7)176 (16.4)79 (17.3)
  • a Comparison between races. RBBB indicates right bundle branch block; IVCD, intraventricular conduction delay; LBBB, left bundle branch block.