Table 2

Power spectral analysis of heart rate variability in patients with schizophrenia v. normal controls

Power spectral analysis1 Patients treated with clozapine Patients treated with haloperidol Patients treated with olanzapine Normal control group Scheffé post hoc test
(n=21) (n=18) (n=17) (n=56)
I II III V
1.Results are expressed as in mean (s.d.) in normalised units using one-way ANCOVA and the covariates of age and smoking.
2.F=77.27, P < 0.0001.
3.F=72.7, P < 0.0001.
4.F=66.7, P < 0.0001.
5.F=11.3, P < 0.0001.
6.F=21.7, P < 0.0001.
7.F=63.08, P < 0.0001.
8.F=10.469, P < 0.0001.
9.F=10.469, P < 0.0001.
10.F=10.469, P < 0.0001.
11.F=10.469, P < 0.0001.
12.F=19.84, P < 0.0001.
13.F=19.84, P < 0.0001.
14.F=4.5, P=0.0064.
Time domain
Mean R-R interval2 568.0 (14.4) 715.8 (33.3) 685.3 (23.9) 961.5 (84.0) I ≠ II, III, V
Standard deviation3 23.79 (3.15) 26.7 (2.6) 26.1 (4.56) 29.26 (6.5) I ≠ II, III, V
Variance4 583.56 (14.4) 731.3 (33.25) 700.9 (23.9) 998.7 (44.7) I ≠ II, III, V
Absolute (log) power values of the frequency bands (ms2)
Low frequency (LF)5 3.58 (0.4) 5.72 (0.4) 5.98 (0.34) 4.6 (1.35) I ≠ II, III, V
High frequency (HF)6 2.32 (0.44) 5.56 (0.37) 5.8 (3.6) 4.6 (1.32) I ≠ II, III, V
Heart rate7 (b.p.m.) 107 (2.7) 85.8 (3.89) 89.05 (3.08) 62 (12.4) I ≠ II, III, V
QT8 518.3 (11.5) 475 (6.4) 474.3 (8.02) 345.2 (5.0)
QTc9 502.9 (12) 517.8 (15.08) 504.6 (7.0) 370 (12.2)
QRS (ms)10 94.5 (18.5) 92.2 (19.3) 95.5 (14.3) 92.1 (18.2) NS
PR (ms)11 150.2 (26.3) 148.2 (24.2) 152.1 (22.3) 151.1 (20.4) NS
Frequency domain
Power
LF (%)12 74.2 (3.46) 53.8 (2.75) 54.1 (2.74) 49.0 (1.5) I ≠ II, III, V
HF (%)13 25.8 (3.46) 46.2 (2.75) 45.9 (2.74) 51.0 (1.5) I ≠ II, III, V
LF/HF (%)14 (mean of individual ratios) 5.9 (1.88) 1.28 (0.18) 1.32 (0.18) 0.96 (0.03) I ≠ V