Q-T and JT dispersion in the elderly with urban hypothermia.

Twenty elderly patients (12 females and 8 males, aged 65-88 years) were treated because of hypothermia: 11 suffered from moderate (35-32 degrees C) and nine from severe hypothermia (<32 degrees C). The control group consisted of 20 age and sex-matched healthy elderly persons. Twelve-channel electrocardiograms were recorded on admission and during hospitalization. In patients with moderate hypothermia Osborn wave was present in eight of 11, and minimal Osborn wave in three of 11; in severe hypothermia Osborn wave was seen in seven of nine, and minimal in two of nine. The corrected Q-T interval (Q-Tc) was analyzed according to the formula of Bazett: measured Q-T(s)/ radical R-R(s). The JT and the corrected JT interval (JTc) were measured according to the formula: JT=Q-T-QRS. The Q-T interval index (Q-TI) was measured according to the formula: (Q-TI:656)x(HR+100); and the JT interval index JTI: (JT:518)x(HR+100). The dispersion of the Q-Tc (JTc) was defined as the difference between maximum and minimum measured Q-Tc interval (JTc). The Q-Tc interval in the group with hypothermia was 651.41+/-130.06 ms, while in the control group it was 398.14+/-76.21 ms (P<0.001). The Q-Tc dispersion in the group with hypothermia was 91.39+/-51.98, and in the control group 33.21+/-10.25 ms (P<0.001). The Q-TcI in the group with hypothermia was 89.91+/-21.44, and in the control group 39.56+/-9.41 ms ((P<0.001). The JTc in the group with hypothermia was 542.66+/-132.74, in the control group: 328.06+/-76.92 (P<0.001). The JTc dispersion in the group with hypothermia was 79.35+/-46.22, and in the control group 28.53+/-7.99 (P<0.0001). The JTcI in the group with hypothermia was 93.06+/-17.38, in the control group it was 40.23+/-7.59 (P<0.001). The mean values of the Q-TcI were greater than Q-TI, and the mean values of the JTcI were greater than JTI, but the difference was not significant (P>0.10). The mean values of the JTcI were greater than Q-TcI, but the difference was not significant as well (P>0.05). There was no correlation between rectal temperature and dispersion of Q-T, Q-Tc, JT, JTc, and Osborn wave. The maximum Osborn wave and the maximum Q-T interval were registered in anteroseptal leads (V(2)-V(3)). The dispersion of the Q-Tc and of the JTc lasted more than Osborn wave. There was no correlation between rectal temperature and PR interval, RR interval and QRS duration. The prolonged dispersion of the Q-Tc (and JTc) last 24-48 h longer than Osborn wave.