Heart rate variability and QT dispersion study in brain death patients and comatose patients with normal brainstem function.

OBJECTIVE To compare heart rate variability (HRV) and QT dispersion in comatose patients with normal brainstem function and with brain death. STUDY DESIGN Cross-sectional comparative study. PLACE AND DURATION OF STUDY The Intensive Care Unit of Ali-Ebn-Abitaleleb Hopital, Rafsanjan Medical University from September 2007 to June 2009. METHODOLOGY Fourteen brain death patients with clinical signs of imminent brain death and 15 comatose patients were examined by neurologist in intensive care unit. HRV, RR interval and QT dispersion on ECG were assessed for 24 hours in both groups. Independent t-test and chi-square test were used for statistical analysis to determine significance which was set at p < 0.05. RESULTS According to Holter findings, mean of standard deviation of RR-interval in the comatose and brain death groups was 48.33 and 35 respectively (p = 0.045). Mean of covariance coefficient of RR-interval was 0.065 in the comatose group and 0.043 in the brain deaths (p = 0.006). QT dispersion was not significant difference in two groups. CONCLUSION HRV and RR-interval analysis appeared as an early finding for the diagnosis of brainstem death in comparison to comatose patients with normal brainstem function. QT dispersion had not significant in this regard.