Journal of neuroimaging : official journal of the American Society of Neuroimaging
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The effect of premature ventricular contractions on blood flow velocity in the middle cerebral artery was studied by transcranial Doppler ultrasonography in 1 0 patients. Velocity during three ectopic beats for each patient was lower than that during the preceding and the following beat in every recording. The decrease in peak velocity was 30.7 ± 12.4% and 37.1 ± 13.3% (mean ± standard deviation) compared to the preceding and following beat, respectively. ⋯ Similar results were obtained for both mean and diastolic blood flow velocities. Systolic-diastolic ratios were similar for premature ventricular contractions, beats preceding or following premature ventricular contractions, and sinus rhythm beats. Transcranial Doppler ultrasound appears to be an excellent technique for analyzing the effects of cardiac arrhythmias on the cerebral circulation.