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Journal ArticleDOI

Pressure-flow studies in man: effect of atrial systole on left ventricular function

01 Mar 1970-Journal of Clinical Investigation (American Society for Clinical Investigation)-Vol. 49, Iss: 3, pp 472-478
TL;DR: The data indicate that in most patients atrial systole is important in augmenting ventricular stroke volume and stroke work especially at high heart rates, but the magnitude of these effects are quite variable among patients.
Abstract: In order to evaluate the effects of atrial contraction on left ventricular function, the pressure gradient technique was used to measure instantaneous aortic blood flow and pressure in nine patients, six having complete heart block and three having normal sinus rhythm. From these data both left ventricular stroke volume and stroke work were calculated. Ventricular rate was controlled by transvenous right ventricular pacing over a range of 50-158 beats/min. At each heart rate, beats which were not preceded by a P wave served as controls. The other beats were divided into six groups according to the duration of the preceding PR interval. The results indicated that stroke volume and stroke work were always affected similarly. In one patient the presence of a P wave did not alter the subsequent stroke volume significantly. In the other patients, beats preceded by P waves had stroke volumes greater than the controls. In general, there was no difference in stroke volume for beats preceded by a P wave having a PR interval within the range of 0.05-0.20 sec. As the PR interval lengthened beyond 0.20 sec stroke volume tended to decrease, especially at more rapid heart rates. The absolute increase in stroke volume after a beat preceded by a P wave (PR interval 0.05-0.20 sec) was quite variable among the patients. For a given patient the absolute increase in stroke volume was essentially independent of heart rate. The percentage change in stroke volume, however, was always greater as the heart rate increased. These data indicate that in most patients atrial systole is important in augmenting ventricular stroke volume and stroke work especially at high heart rates, but the magnitude of these effects are quite variable among patients.

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Citations
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Journal ArticleDOI
TL;DR: Atrial contribution tends to be less effective in augmenting cardiac output when filling pressure is already elevated, particularly in patients with impaired left ventricular function.

321 citations

Journal ArticleDOI
TL;DR: The left atrial contribution to left ventricular function is increased in patients with remote myocardial infarction, attributed to the Frank- Starling mechanism in the left atrium.
Abstract: Left atrial function was evaluated in patients with and without remote myocardial infarction. The simultaneous left atrial pressure recording and left atrial and left ventricular cineangiograms were obtained with a catheter-tip micromanometer. The pressure-volume curve of the left atrium was composed of an A-loop and a V-loop. The ratio of active atrial emptying to left ventricular stroke volume in patients with myocardial infarction was significantly larger than that in normal subjects (42 +/- 12% vs 29 +/- 10%, p less than 0.05). The left atrial work was also significantly greater in patients with myocardial infarction (1690 +/- 717 mm Hg X ml) than in normal subjects (940 +/- 426 mm Hg X ml, p less than 0.05). The ratio of active atrial emptying to left ventricular stroke volume and left atrial work were significantly related in both normal subjects and patients with myocardial infarction (gamma = 0.72, p less than 0.01). The left ventricular ejection fraction correlated inversely with left atrial work (gamma = -0.5, p less than 0.05). Left atrial work also showed a significant linear correlation with left atrial volume before active atrial emptying (gamma = 0.82, p less than 0.01). We conclude that the left atrial contribution to left ventricular function is increased in patients with remote myocardial infarction. This left atrial contribution to the left ventricle is attributed to the Frank-Starling mechanism in the left atrium.

288 citations

Journal ArticleDOI
TL;DR: In patients with myocardial infarction, atrial contraction made a large contribution to left ventricular filling and stroke volume irrespective of the type ofleft ventricular functional derangement that was present.

241 citations

Journal ArticleDOI
TL;DR: The recent development of a noninvasive evaluation of the pattern of LV diastolic filling by RNA or Doppler echocardiography is an important advance and when interpreted with an understanding of the determinants of LV filling and the patient's clinical status, these noninvasively evaluated tests can contribute to the rational assessment of LVdiastolic performance.

215 citations

Journal ArticleDOI
TL;DR: In this paper, the authors determined whether age-related alterations in Doppler diastolic filling indexes occur independent of cardiovascular disease and confounding physiologic variables, and showed that peak early and atrial flow velocities were not related to any of the parameters measured once age was accounted for, although peak filling rate was related to body surface area as well as age.

209 citations

References
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Journal ArticleDOI
TL;DR: Evidence was presented to show that, under varying conditions, the duration of the ejection phase is modified by factors other than theduration of preceding diastole, and the conclusion naturally followed that the volume curves of the ventricles cannot be superimposable under such conditions of the heart beat.
Abstract: In several recent communications from this laboratory (I), (2), (3) evidence was presented to show that, under varying conditions, the duration of the ejection phase is modified by factors other than the duration of preceding diastole. The conclusion naturally followed that the volume curves of the ventricles cannot be superimposable under such conditions of the heart beat. These deductions should, however, be capable of direct demonstration when ventricular volume curves are taken during similar changes in the circulation; and, in addition, the precise character of the alterations in filling and expulsion accompanying such phasic changes should be determinable, provided, of course, that it is possible to record changes in systolic ejection and diastolic filling with a sufficient degree of accuracy. Before proceeding with a narration of the results obtained in such an investigation, it is important to delineate, as they appear to us, the principles and practice concerned in volumetric studies of the ventricles. It is desirable also to analyze the character of representative volume curves and to point out the features which readily lend themselves to misinterpretation.

289 citations


"Pressure-flow studies in man: effec..." refers background in this paper

  • ...Early studies in animals by Gesell (12) and Wiggers and Katz (13) documented the importance of atrial contraction in augmenting ventricular performance....

    [...]

Journal ArticleDOI
TL;DR: It is suggested that depressed atrial function, i.e., atrial failure, may be a significant contributory factor in the elevated venous pressure observed in congestive heart failure.
Abstract: Mean left atrial pressure is higher for any given left ventricular end diastolic pressure, as the heart rate is progressively increased, for two reasons. First, by encroaching on ventricular diastole, the relative period during which inflow into the atrium continues while the egress of blood from the atrium is blocked is increased. Second, with more severe tachycardia, atrial systole can be seen to occur either partially or completely while the mitral valve is still closed from the previous ventricular systole. At a constant heart rate, mean left atrial pressure is higher for any given left ventricular end diastolic pressure during efferent vagal nerve stimulation than during control conditions. This is due to a negative inotropic effect on the atrium and not to a change in the performance characteristics of the ventricle. At a constant heart rate, mean left atrial pressure is lower for any given left ventricular end diastolic pressure during cardiac sympathetic nerve stimulation than during control conditions. This is due to a positive inotropic effect on both the atrium and the ventricle. The relation between left ventricular end diastolic pressure and stroke work is determined only by the performance characteristics of the ventricle; the relation between mean left atrial pressure and stroke work is determined by the performance characteristics not only of the ventricle but also to a substantial extent by those of the atrium. Atrial contractility and the changes therein induced by central nervous system activity are of importance to circulatory regulation both because of the influence of atrial systole on ventricular end diastolic pressure and because of the effect of such changes on central venous pressure at any given level of ventricular stroke work. The possibility is suggested that depressed atrial function, i.e., atrial failure, may be a significant contributory factor in the elevated venous pressure observed in congestive heart failure.

216 citations


"Pressure-flow studies in man: effec..." refers background in this paper

  • ...Experimental data in animals have shown that atrial contraction plays an important role in maintaining adequate cardiac function, especially at rapid heart rates (1-4)....

    [...]

Journal ArticleDOI
TL;DR: The use of heart block dog preparations allowed an investigation at constant ventricular rates of the hemodynamic effects which resulted when the timing of atrial systole was altered relative to the resting heart.
Abstract: The use of heart block dog preparations allowed an investigation at constant ventricular rates of the hemodynamic effects which resulted when the timing of atrial systole was altered relative to ve...

170 citations

Journal ArticleDOI
TL;DR: A method is described for the continuous recording of changes in the length of a segment of left ventricular myocardium, and its advantages and limitations are discussed.
Abstract: A method is described for the continuous recording of changes in the length of a segment of left ventricular myocardium, and its advantages and limitations are discussed The curve depicting the relation between ventricular diastolic pressure and simultaneous changes in the length of a myocardial segment is presented For a given increment in pressure, the myocardial segment length increases more at low ventricular diastolic pressure than at high pressure Atrial systole causes a substantial increase in myocardial segment length when the ventricle is on the sensitive part of its pressure-length curve

141 citations


"Pressure-flow studies in man: effec..." refers background in this paper

  • ...Experimental data in animals have shown that atrial contraction plays an important role in maintaining adequate cardiac function, especially at rapid heart rates (1-4)....

    [...]

Journal ArticleDOI

130 citations


"Pressure-flow studies in man: effec..." refers background in this paper

  • ...Early studies in animals by Gesell (12) and Wiggers and Katz (13) documented the importance of atrial contraction in augmenting ventricular performance....

    [...]