Effect Of Ventricular Rate Research Articles

The impact of atrial fibrillation on accuracy of oscillometric blood pressure measurement: effect of ventricular rate.

This study evaluated the impact of ventricular rate (VR) in atrial fibrillation (AF) patients with oscillometric BP measurements. This study included 138 patients with AF and 112 patients with sinus rhythm (SR) who underwent coronary angiography. Left arm BP was measured three times with an oscillometric device, and the average was recorded as the final oscillometric value. At the same time, the average of three intra-aortic BP readings was used as invasive values. Delta BP was the difference between intra-aortic and oscillometric BP. Meanwhile, the BP percentage difference (PD-BP) was calculated with the following formula: PD-BP = (delta BP/intra-aortic BP) × 100%. Based on the VR, four subgroups of AF and SR patients, <80, 80-99, 100-120, and >120 bpm, were created, and the mean PD-BP for both systolic blood pressure (SBP) and diastolic blood pressure (DBP) was significantly higher in the AF group than in the SR group. Moreover, the mean PD-SBP values gradually increased as VR increased in both groups. More importantly, the difference in PD-SBP between the AF and SR groups increased as VR increased: when VR was <80 bpm, the levels were similar (-2.0 ± 3.5 vs. -1.4 ± 2.7 mm Hg, NS), but these values in AF patients were significantly higher when VR was 80-99 bpm (-3.7 ± 5.0 vs. -1.8 ± 2.3 mm Hg, p < 0.05), 100-120 bpm (-6.1 ± 4.3 vs. -2.3 ± 1.9 mm Hg, p < 0.05) and >120 bpm (-7.8 ± 4.9 vs. -2.9 ± 1.7 mm Hg, p < 0.05). The accuracy of oscillometric BP measurements are dependent on the ventricular rate in AF patients even after three measurements, and a higher ventricular rate may result in larger underestimations of oscillometric BP.

The heart-ventricular function.

AnaesthesiaVolume 23, Issue 4 p. 566-584 Free Access The heart-ventricular function R. J. Linden, R. J. Linden R. J. Linden, Professor of Applied Physiology, Cardiovascular Unit, Department of Physiology, University of Leeds and Director, Cardiovascular Investigation Unit, The General Infirmary, and Killingbeck Hospital, Leeds.Search for more papers by this author R. J. Linden, R. J. Linden R. J. Linden, Professor of Applied Physiology, Cardiovascular Unit, Department of Physiology, University of Leeds and Director, Cardiovascular Investigation Unit, The General Infirmary, and Killingbeck Hospital, Leeds.Search for more papers by this author First published: December 1968 https://doi.org/10.1111/j.1365-2044.1968.tb00120.xCitations: 10AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat References 1 LINDEN, R. J. (1963). The control of the output of the heart, in R. Creese (ed.) Recent Advances in Physiology, 8th ed., p. 330. London : Churchill. 2 LINDEN, R. J. (1965). The regulation of the output of the mammalian heart. Scient. Basis Med. ann. Rev., p. 164. 3 MILLER, D. E., GLEASON, W. L., WHALEN, R. E., MORRIS, J. J. and MCINTOSH, H. D. (1962). Effect of ventricular rate on the cardiac output in the dog with chronic heart block. Circulation Res., 10, 658. 4 BEVEGARD, S., JONSSON, B., KARLÖF, I., LAGERGREN, H. and SOWTON, E. (1967). Effect of changes in ventricular rate on cardiac output and central pressures at rest and during exercise in patients with artificial pacemakers. Cardiovasc. Res., 1, 21. 5 RUSHMER, R. F. (1959). Constancy of stroke volume in ventricular responses to exertion. Am. J. Physiol., 196, 745. 6 BRUTSAERT, D. (1965). Influence of different stimulation frequencies on the cardiac output at rest and during moderate exercise in dogs with chronic atrioventricular heart block. Acta, cardiol., 20, 469. 7 STARLING, E. H. (1918). The Linacre Lecture on the Law of the Heart given at Cambridge, 1915. London : Longmans, Green. 8 SONNENBLICK, E. H. (1962). Force-velocity relations in mammalian heart muscle. Am. J. Physiol., 202, 931. 9 ROSENBLUETH, A., ALANIS, J., RUBIO, R. and LÓPEZ, F. (1959). The two staircase phenomena. Archs. int. Physiol., 67, 374. 10 BRAUNWALD, E. (1965). The control of ventricular function in man. Br. Heart J., 27, 1. 11 SARNOFF, S. J., BROCKMAN, S. K., GILMORE, J. P., LINDEN, R. J. and MITCHELL, J. H. (1960). Regulation of ventricular contraction: influence of cardiac sympathetic and vagal nerve stimulation on atrial and ventricular dynamics. Circulation Res., 8, 1108. 12 LEONARD, E. and HAJDU, S. (1962). Action of electrolytes and drugs on the contractile mechanism of the cardiac muscle cell, in W. F. Hamilton (ed.) Handbook of Physiology, Section 2. Circulation, Vol. 1, p. 151. Washington : American Physiological Society. 13 WALLACE, A. G., SKINNER, N. S. and MITCHELL, J. H. (1963). Hemodynamic determinants of the maximal rate of rise of left ventricular pressure. Am. J. Physiol., 205, 30. 14 COVELL, J. W., ROSS, J., TAYLOR, R., SONNENBLICK, E. H. and BRAUNWALD, E. (1967). Effects of increasing frequency of contraction on the force velocity relation of left ventricle. Cardiovasc, Res., 1, 2. 15 FURNIVAL, C. M., LINDEN, R. J. and SNOW, H. M. (1967). An assessment of the effect of the sympathetic nerves to the heart. J. Physiol., Lond. 191, 60P. 16 FURNIVAL, C. M., LINDEN, R. J. and SNOW, H. M. (1968). An index of the inotropic effect of an adrenergic agent on the heart. J. Physiol., Lond., 196, 41P. 17 EPSTEIN, S. E., ROBINSON, B. F., KAHLER, R. L. and BRAUNWALD, E. (1965). Effects of beta-adrenergic blockade on the cardiac response to maximal and submaximal exercise in man. J. clin. Invest., 44, 1745. 18 DONALD, D. E., FERGUSON, D. A. and MILBURN, S. E. (1968). Effect of beta-adrenergic receptor blockade on racing performance of greyhounds with normal and denervated hearts. Circulation Res., 22, 127. Citing Literature Volume23, Issue4December 1968Pages 566-584 ReferencesRelatedInformation

Unusual observations during pacemaker therapy for complete heart block

During the course of management of spontaneously occurring complete heart block with Stokes-Adams syndrome in a 10 year old boy, rare clinical, therapeutic and physiologic observations were made. Initially, cardiac rate was controlled via a catheter electrode. The effect of ventricular rate on right atrial pressure was shown. There was a progressive fall in right atrial pressure as the ventricular rate was increased from 36 to 100/min. A Chardack pacemaker was implanted permanently, and cardiac rate was controlled with a 9-volt stimulus. During steroid therapy, retrograde atrial conduction and normal sinus rhythm developed. Unusual cardiac arrhythmias allowed electrocardiographic data to be obtained concerning the “vulnerable period” of the cardiac cycle in man. During alternating periods of normal sinus rhythm and pacemaker-controlled rate, ventricular premature beats resulted only when stimuli fell in a period of less than 30 msec, preceding the apex and during the descending portion of the T wave. Additionally, it was shown that stimuli in the “vulnerable period” of the cardiac cycle resulted in premature beats with QRS complexes of “multiform” shape. Although a single stimulus (considerably above the premature beat threshold value) placed in the vulnerable period can initiate ventricular fibrillation, a 9-volt stimulus was insufficient to reach ventricular fibrillation threshold in our patient. Steroid therapy was discontinued with subsequent loss of atrioventricular conduction. Pacemaker failure (due to breakage of a resistor wire) occurred 12 months postoperatively. Successful substitution of the abdominal wall pacemaker was made. At the time of pacemaker substitution, the threshold voltage required to control ventricular rate was 4.6 volts indicating that there had been no significant increase in myocardial resistance after one year.

Effect of Ventricular Rate on the Cardiac Output in the Dog with Chronic Heart Block

The effect of heart rate on cardiac output and associated rate induced hemodynamic changes in dogs with chronic heart block is presented and discussed. At heart rates below 60/min., the stroke volume was maximum and relatively constant, and the cardiac output was largely rate-dependent. These relationships did not exist at ventricular rates above 60/min. Cinefluorographic evidence of decreased diastolic ventricular filling with increasing ventricular rates is presented. At very slow and very fast ventricular rates, the cardiac output decreased despite an increase in right atrial and right ventricular end-diastolic pressure. At slow rates the decreased output was due to rate alone, while at rapid rates it was attributed to the decreased diastolic filling period and resistance to ventricular distention, resulting in decreased diastolic filling.