Cerebrovascular Hemodynamic Inefficiency of Premature Ventricular Contractions

Abstract

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). Peak systolic velocities averaged 74 ± 6 cm/sec for the NSR and 45 ± 7 cm/sec in the PVC group (P = 0.016). The latency between the QRS complexes and corresponding TCD wave forms (QRS-SU) averaged 0.12 ± 0.03 sec in NSR and 0.17 ± 0.04 sec for the PVC group (P < 0.001). 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.

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References

Hinkle LE , Carver ST , Stevens M. : The frequency of asymptomatic disturbances of cardiac rhythm and conduction in middle-aged men. Am J Cardiol 24:629, 1969.

Lundberg GB : Standards and guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiac care (ECC). JAMA 255:2843, 1986 .

Ameriso SF , Fisher M. , Sager P. : Effect of premature ventricular contractions on middle cerebral artery blood flow velocity. J Neuroimag 1:129-133, 1991.

Saver JL , Feldmann E. : Basic transcranial Doppler examination: Technique and anatomy. In: Transcranial Doppler Ultrasonography, ed. by Babikian VL , Wechsler LR. St. Louis: Mosby, 1993, pp 11-28

Rosenbaum MB : Classification of ventricular extrasystoles according to form. J Electrocardiol 2:289-297, 1969.

Cohn K. , Krydaw W. : The influence of ectopic beats and tachyarrhythmias on stroke volume and cardiac output. J Electrocardiol 14:207-218, 1981.

O'Rourke RA : Physical examination of the arteries and veins (including blood pressure determination) . In: The Heart, ed. 6, ed. by Hurst JW. New York: McGraw-Hill, 1986, pp 138-151.

Noble Mim : The Cardiac Cycle. Oxford: Blackwell Scientific Publications Ltd., 1979.