['The present study was undertaken to assess whether the vertical displacement of electrodes affects the waveforms of precordial leads.', 'Two hundred forty healthy, adult volunteers had a standard 12-lead electrocardiogram, a 12-lead electrocardiogram with the precordial leads displaced 2 cm cranially, and another with the precordial leads displaced 2 cm caudally from the standard positions. All the three sets of electrocardiograms were visually compared, and changes noted. One hundred twenty male and 120 female volunteers, 20-68 years of age, were analyzed. Fifty-four males (45.0%) and 2 females (1.7%) showed no difference between the 3 sets of electrocardiograms, while 66 males (55.0%) and 118 females (98.3%) had some changes. R wave amplitude changes were noted in 63 male (52.5%) and 111 female (92.5%) volunteers; S wave amplitude changes were seen in 59 males (49.2%) and 99 females (82.5%,); T wave changes in 5 males (4.2%) and 3 females (2.5%); ST segment changes in 1 male (0.8%) and none of the females; and ORS morphologic changes in 1 male (0.8%) and 12 females (10.0%).'] Does vertical displacement of the precordial leads alter electrocardiographic morphology?