Cardiovascular disorders such as decreased heart rate variability, orthostatic hypotension, and arrhythmias have been frequently observed in Parkinson's disease (PD) patients. In this study, authors measured P wave duration and dispersion in PD patients and controls. Twenty-three consecutive patients with idiopathic PD and sex-age matched 23 control subjects were included to the study. A 12-lead surface ECG was obtained from each participant. Maximum-minimum P wave duration and P wave dispersion (PWD) were measured in both groups. Maximum P wave duration was found to be higher in PD patients than controls (117 +/- 12 vs. 105 +/- 9 ms p=0.001). Minimum P wave duration was similar in PD patients and controls (64 +/- 11 vs. 63 +/- 11 msp=0.7). PWD in PD patients was also found to be higher than those of controls (53 +/- 11 vs. 43 +/- 10 ms p=0.0001). P wave duration and PWD did not significantly differ between PD patients taking anti-parkinsonian agents from those who were not (119113 vs. 116 +/- 13 ms p=0.4 and 55 +/- 11 vs. 52 +/- 11 ms p=0.5, respectively). Moreover, when the PD patients taking anti-parkinsonian agents were excluded from the study, PD patients had still higher P wave duration and PWD compared to controls (119 +/- 11 vs. 105 +/- 9 ms p=0.004, 52 +/- 10 vs. 43 +/- 10 ms p=0.009, respectively). In conclusion, we found that P wave duration and PWD were greater in PD patients compared to control subjects. (c) 2006 Elsevier Inc. All rights reserved.