Left Ventricular Performance Following Correction of Free Aortic Regurgitation
TLDR
A fixed abnormality in diastolic LV pressure-volume characteristics, determined from preoperative and postoperative measurements of pressure and radius during diastole, had occurred in patients with depressed myocardial function, suggesting reversal of stress relaxation, or creep, following relief of volume overload.Abstract:
Left ventricular (LV) myocardial contractility, or inotropic state, was characterized in terms of the instantaneous relations between velocity of circumferential fiber shortening (VCF), determined cineangiographically, and LV wall tension (hoop stress), calculated from LV dimensions and pressure, in five patients before and 7 to 10 mo after aortic valve replacement for free aortic regurgitation. Preoperatively the cardiac index was reduced or the LV end-diastolic pressure was markedly increased (or both occurred) in four patients, in each of whom depression of inotropic state was documented by a reduced VCF at maximum wall tension, ranging from 0.13 to 1.07 circumferences (circ)/sec (normal, > 1.40 circ/sec) at wall tensions of 318 to 464 g/cm2 (normal, 178 to 417 g/cm2). In one patient in whom LV end-diastolic pressure and cardiac index were normal preoperatively, VCF was 1.66 circ/sec at a maximum tension of 440 g/cm2. Following operation, LV end-diastolic pressure fell in the four patients with depress...read more
Citations
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Afterload mismatch and preload reserve: a conceptual framework for the analysis of ventricular function.
TL;DR: The concept of afterload mismatch with limited preload reserve provides an explanation for the value of ejection phase indices compared to isovolunic phase measures in assessing the basal level of inotropic state: the former may be more reliable because they are sensitive to afterload.
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Cardiac hypertrophy: useful adaptation or pathologic process?
TL;DR: An extensive body of evidence supports the concept that cardiac hypertrophy and normal cardiac growth develop in response to increased hemodynamic loading and abnormal systolic and diastolic stresses at the myocardial fiber level.
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Diastolic Properties of the Left Ventricle
TL;DR: Left ventricular pressure and volume during diastole reflect the interaction of ventricular elastic, viscous, and inertial properties, and the completeness of myocardial relazation, and may be impaired in the acutely ischemic ventricle.
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Left ventricular compliance: mechanisms and clinical implications.
TL;DR: The pathophysiology of pulmonary congestion is best understood by considering the factors responsible for producing changes in chamber stiffness of the ventricle, whereas an examination of muscle stiffness is likely to provide more insight into the extent of irreversible functional and structural defects of the myocardium.
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Effects of changes in preload, afterload and inotropic state on ejection and isovolumic phase measures of contractility in the conscious dog.
TL;DR: All of the indexes studied were comparably sensitive to acute alterations in contractility, but it is concluded that no single measure can always be used for defining an acute contractility change in the intact circulation.
References
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Contractile State of the Left Ventricle in Man: Instantaneous Tension-Velocity-Length Relations in Patients With And Without Disease of the Left Ventricular Myocardium
TL;DR: The contractile state of the left ventricle in man was analyzed by correlating left ventricular dimensional changes during contraction determined from cineangiograms, with simultaneous measurements of LV pressure and the time course of LV wall tension (stress).
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Myocardial mechanics in aortic and mitral valvular regurgitation: the concept of instantaneous impedance as a determinant of the performance of the intact heart
TL;DR: It is concluded that the impedance to ejection and myocardial fiber tension during ejection govern the velocity and extent of contractile element shortening, and hence affect stroke volume, peak aortic flow rate, and ejection fraction.
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Hemodynamic Effects of Quantitatively Varied Experimental Aortic Regurgitation
TL;DR: A canine preparation was devised in which aortic regurgitant flow could be acutely produced, metered and controllably varied, and effective cardiac output, stroke work and left ventricular end-diastolic pressure fell, while left atrial pressure rose.
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Myocardial Function and Left Ventricular Volumes in Acquired Valvular Insufficiency
TL;DR: The effect of valvular insufficiency on left ventricular volumes was studied by an angiographic method in 37 patients and results show good agreement with subsequent surgical findings in the 15 patients who underwent operation.
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Left Ventricular Volumes in Valvular Heart Disease
John W. Jones,Charles E. Rackley,Robert A. Bruce,Harold T. Dodge,Leonard A. Cobb,Harold Sandler +5 more
TL;DR: Left ventricular volumes were determined in 86 patients with aortic and mitral valve disease by use of a biplane angiocardiographic technicin conjunction with cardiac catheterization and there was no correlation between end-diastolic pressure and either total stroke volume or end- diastolic volume.