Angiology
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Transcranial Doppler (TCD) measurements of middle cerebral artery (MCA) blood flow velocities were recorded and synchronized with electrocardiographic (EKG) recordings in 52 EKG/TCD complexes in 4 patients. Thirty-seven normal sinus beats and 13 conductive and 2 nonconductive premature ventricular contractions (PVCs) were examined. Mean velocities averaged 45 +/- 4 cm/sec for normal sinus rhythm (NSR) vs 26 +/- 4 cm/sec in the PVC group (P = 0.007). ⋯ In addition, QRS-SU was inversely related to all velocities. PVCs appeared to be less hemodynamically efficient than NSR. The lower blood flow velocities and increased QRS-SU may result from lower stroke volume and delayed ventricular contraction associated with the aberrant QRS complex.