Studies on Starling's Law of the Heart. Iii. Observations in Patients With Mitral Stenosis and Atrial Fibrillation on the Relationships Between Left Ventricular End-Diastolic Segment Length, Filling Pressure, and the Characteristics of Ventricular Contraction *

Braunwald, Eugene; Frye, Robert L.; Aygen, M; Gilbert, Joseph W.

doi:10.1172/jci104211

Cited by 79 publications

(17 citation statements)

References 35 publications

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“…In the present study, the mean circumferential length of the strong beats at end-diastole (7.3 cm) was only 4 mm, or approximately 5% greater than the mean end-diastolic circumferential length of the weak beats (6.9 cm). Extrapolating from two studies of the relation of muscle length to ventricular pressure and stroke volume in the human heart, it seems reasonable to assume that a 5% alternation in end-diastolic circumference would substantially influence ventricular performance (4,23). In certain of our experiments, e.g.…”

Section: Resultsmentioning

confidence: 78%

The demonstration of alternating contractile state in pulsus alternans

Noble¹,

Nutter²

1970

J. Clin. Invest.

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A B S T R A C T Pulsus alternans was induced in 11anesthetized, open-chest dogs by rapid atrial pacing, and the left ventricular filling characteristics and lengthtension-velocity relationship of alternating beats were compared. The end-diastolic circumferences (circ) of the strong beats were slightly, but significantly, increased over the weak beats (7.3 > 6.9 cm, P < 0.01), confirming that diastolic filling does alternate in pulsus alternans. This alternation in initial fiber length seemed to result from an alternation in the prior end-systolic length, rather than from an alternation in diastolic filling time or compliance. There was also no difference in enddiastolic tension as measured by an isometric strain gauge suggesting no difference in contractile element relaxation before weak and strong beats.The contractile state of the strong beats was consistently greater than that of the weak beats when contractility was defined in terms of: (a) Vmax (3.13 > 2.53 circ/sec, P <0.01); and (b) the velocity of circumferential fiber shortening (0.84 > 0.39 circ/sec, P < 0.001) and developed tension (82.5 > 74 g/cm, P < 0.01) at isolength. The length-tension-velocity relationship of the left ventricle also varied between strong and weak beats when: (a) the maximum velocity of contractile element shortening at least common tension (1.68> 1.28 circ/sec, P <0.05); and (b) the velocity of circumferential fiber shortening (0.81 > 0.39 circ/ sec, P < 0.001) at maximum developed tension were examined. Analysis of the length-tension-velocity characteristics of sequential beats at the onset of alternans in three dogs suggests that an alternation in contractility initiates alternans, with secondary alternations in ventricular filling. Cross-clamping of the aorta in three

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Section: Resultsmentioning

confidence: 78%

The demonstration of alternating contractile state in pulsus alternans

Noble¹,

Nutter²

1970

J. Clin. Invest.

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“…Although evaluation of LV performance during AF is inherently difficult because of its beat-to-beat variability, the role of the preceding RR intervals has been well established in determining LV systolic function (1,9,11,12,16,18,20,21). Specifically, the LV systolic variables show positive and negative linear relationships with RR 1 and RR 2 intervals, respectively (9,11,12,18).…”

Section: Discussionmentioning

confidence: 99%

Determinants of LV diastolic function during atrial fibrillation: beat-to-beat analysis in acute dog experiments

Tabata

Grimm

Asada

et al. 2004

American Journal of Physiology-Heart and Circulatory Physiology

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N. Mazgalev. Determinants of LV diastolic function during atrial fibrillation: beat-to-beat analysis in acute dog experiments. Am J Physiol Heart Circ Physiol 286: H145-H152, 2004. First published September 4, 2003 10.1152/ ajpheart.00588.2003 diastolic function during atrial fibrillation (AF) remains poorly understood due to the complex interaction of factors and beat-to-beat variability. The purpose of the present study was to elucidate the physiological determinants of beat-to-beat changes in LV diastolic function during AF. The RR intervals preceding a given cardiac beat were measured from the right ventricular electrogram in 12 healthy open-chest mongrel dogs during AF. Doppler echocardiography and LV pressure and volume beat-tobeat analyses were performed. The LV filling time (FT) and early diastolic mitral inflow velocity-time integral (Evti) were measured using the pulsed Doppler method. The LV end-diastolic volume (EDV), peak systolic LV pressure (LVP), minimum value of the first derivative of LV pressure curve (dP/dtmin), and the time constant of LV pressure decay () were evaluated with the use of a conductance catheter for 100 consecutive cardiac cycles. Beat-to-beat analysis revealed a cascade of important causal relations. LV-FT showed a significant positive linear relationship with Evti (r ϭ 0.87). Importantly, there was a significant positive linear relationship between the RR interval and LV-EDV in the same cardiac beat (r ϭ 0.53). Consequently, there was a positive linear relationship between LV-EDV and subsequent peak systolic LVP (r ϭ 0.82). Furthermore, there were significant positive linear and negative curvilinear relationships between peak systolic LVP and dP/dtmin (r ϭ 0.95) and (r ϭ Ϫ0.85), respectively, in the same cardiac beat. In addition, there was a significant negative curvilinear relationship between dP/dt min and (r ϭ Ϫ0.86). We have concluded that the determinants of LV diastolic function in individual beats during AF depend strongly on the peak systolic LVP. This suggests that the major benefit of slower ventricular rate appears related to lengthening of LV filling interval, promoting subsequent higher peak systolic LVP and greater LV relaxation. filling interval; left ventricular pressure ATRIAL FIBRILLATION (AF) has been long recognized as one of the most frequent chronic arrhythmias, affecting 0.9% of the population and characterized by irregular rhythm (6). The rapid ventricular rate adversely affects left ventricular (LV) function as preload and contractility diminish due to shorter filling intervals. Furthermore, the absence of optimal atrial boosterpump function as well as beat-to-beat changes in preload, afterload, and contractility are serious negative hemodynamic consequences of AF. They may cause severe LV systolic dysfunction similar to tachycardia-induced cardiomyopathy, even in the absence of other heart disease (10).It is well recognized that patients with normal sinus rhythm who arrive at the hospital with heart failure are frequently found to have diastolic ra...

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“…It was demonstrated in earlier studies carried out in this laboratory that marked alterations in left ventricular end-diastolic segment length and pressure occur as a consequence of variations in the duration of filling in the presence of atrial fibrillation (34) or as a result of variations in the effectiveness of atrial contraction in atrioventricular dissociation (41); the force of left ventricular contraction was found, in each instance, to be a function of the left ventricular end-diastolic segment length and, in the absence of tachycardia, of the left ventricular end-diastolic pressure as well. These results are entirely in accord with those obtained in the present investigation in which a different technic for varying ventricular filling was utilized.…”

Section: Methodsmentioning

confidence: 93%

“…Recent observations in the dog have demonstrated that the relationship between effective left ventricular enddiastolic pressure and segment length is unaffected by stimulation of the cardiac sympathetic nerves or of the vagi (32) and by large changes of systemic arterial pressure and of cardiac output (33). It has also been shown in man that in the absence of tachycardia, changes in the effective left ventricular end-diastolic pressure may be utilized to indicate alterations in left ventricular dimensions (34). Thus, without the availability of a suitable technic capable of providing accurate serial measurements of left ventricular volume in man, left ventricular and intraesophageal pressures were measured in order to permit measurement of changes in effective left ventricular enddiastolic pressure.…”

Section: Methodsmentioning

confidence: 99%

Studies on Starling's Law of the Heart. V. Left Ventricular Function in Man

Braunwald¹,

Frahm²,

Ross³

1961

J. Clin. Invest.

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There is general agreement that the force of contraction developed by strips of cardiac muscle is a function of the length of the fibers at the onset of contraction (1-3). Similarly, in the isolated heart (4), the heart-lung preparation (5) and in the open-chest, anesthetized dog (6-8), the energy of contraction, as reflected by the external work performed by the ventricle, has been shown to be dependent upon the ventricular end-diastolic fiber length or pressure. These observations have been interpreted to be consistent with the concept enunciated by Starling in his Linacre lecture on "The Law of the Heart (9).However, no such general agreement exists regarding the applicability of Starling's law of the heart to the circulation of human subjects. This lack of information regarding the relationship between left ventricular end-diastolic pressure (and fiber length) and the characteristics of ventricular contraction in man is understandable when it is considered that only recently have methods been developed which are suitable for the direct measurement of left ventricular pressure in subjects without cardiovascular disease (10). One of the experimental approaches which has been employed to test the validity of Starling's law has been a study of the hemodynamic response resulting from acutely induced hypervolemia (11)(12)(13)(14)(15). A variety of fluids has been infused in attempts to simulate in man the increase in venous return to the Starling heart-lung preparation. In several such investigations an augmentation of the total blood volume has not been associated with a significant elevation of cardiac output (13-15).The purpose of the present investigation was to define the relationships between left ventricular end-diastolic pressure and the characteristics of left ventricular contraction in a group of subjects without cardiovascular disease. Acutely induced hypervolemia was combined with continuous ganglionic blockade in order to produce significant variations in ventricular filling and thus to permit an examination of Starling's law of the heart. METHODSix male subj ects averaging 25 years in age were studied. All had provided informed consent for these studies. Five of these subj ects were referred to the National Heart Institute for cardiac catheterization because of the presence of systolic heart murmurs. Clinical examination was otherwise negative, chest roentgenograms and electrocardiograms were within normal limits, and these murmurs were considered to be functional in origin. The sixth subject, J.M., a 32 year old male, was studied three months after repair of a small ventricular septal defect. He had never experienced symptoms of diminished cardiac reserve, had not had cardiac enlargement on roentgenographic examination and his pulmonary arterial pressure was within normal limits (16) prior to operation as well as at the time of this study. Three or four phlebotomies were performed on each subject over a period of 7 to 10 days and the 1,500 ml of blood so obtained was stored in solutions of sodium ci...

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Studies on Starling's Law of the Heart. Iii. Observations in Patients With Mitral Stenosis and Atrial Fibrillation on the Relationships Between Left Ventricular End-Diastolic Segment Length, Filling Pressure, and the Characteristics of Ventricular Contraction *

Cited by 79 publications

References 35 publications

The demonstration of alternating contractile state in pulsus alternans

The demonstration of alternating contractile state in pulsus alternans

Determinants of LV diastolic function during atrial fibrillation: beat-to-beat analysis in acute dog experiments

Studies on Starling's Law of the Heart. V. Left Ventricular Function in Man

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