Indexed Mitral Annulus Plane Systolic Excursion Is a Reliable Surrogate for Index Left Ventricle Stroke Volume

THE mechanisms of adaptation of the left ventricle to the demands of muscular exercise have intrigued cardiovascular physiologists for many years. Although highly complex, these adaptive mechanisms are more and more susceptible to analysis and quantification. In this presentation I will attempt to identify some of the individual factors which appear to be important in the response of the left ventricle to exercise, beginning with data obtained from experiments on conscious normal male subjects and proceeding to experiments performed on dog preparations in which individual factors were controlled and analyzed. The changes in oxygen intake, cardiac output, estimated arteriovenous oxygen difference, pulse rate and estimated mean stroke volume were determined in 15 normal male subjects during rest in the standing position and during treadmill exercise at the maximal oxygen intake level. Oxygen intake was obtained from the volume and composition of expired air, cardiac output by the dye dilution technique, and pulse rate from the electrocardiogram. Estimated arteriovenous oxygen difference was obtained by dividing the oxygen intake by the cardiac output (Fick principle) and estimated mean stroke volume by dividing the cardiac output by the heart rate. The data are shown in Figure 1. Oxygen intake increased from a mean value of 0.34 at rest to a maximal value of 3.22 L./min. The corresponding mean values for cardiac output were 5.4 and 23.4 L./min. and for arteriovenous oxygen difference were 6.5 and 14.3 ml./100 ml. Thus, as oxygen intake increased 9.5 times, the cardiac output increased 4.3 times and the arterio venous oxygen difference 2.2 times.

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Longitudinal Mitral Annulus Velocities Are Reduced in Hypertensive Subjects With or Without Left Ventricle Hypertrophy

Hypertension ◽

10.1161/01.hyp.0000216123.57284.b0 ◽

2006 ◽

Vol 47 (5) ◽

pp. 854-860 ◽

Cited By ~ 30

Author(s):

Maria Cândida C. Borges ◽

Roberta C.R. Colombo ◽

José Geraldo F. Gonçalves ◽

José de Oliveira Ferreira ◽

Kleber G. Franchini

Keyword(s):

Left Ventricle ◽

Mitral Annulus ◽

Left Ventricle Hypertrophy ◽

Ventricle Hypertrophy

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Mitral annulus and left atrium wall abscess fistulized to the left ventricle

European Heart Journal - Cardiovascular Imaging ◽

10.1093/ejechocard/jer074 ◽

2011 ◽

Vol 12 (8) ◽

pp. 584-584 ◽

Cited By ~ 2

Author(s):

Jesús Zarauza ◽

Jose A. Vázquez de Prada ◽

Jose M. Cuesta ◽

Pilar Ortiz ◽

Salvador Diez-Aja ◽

...

Keyword(s):

Left Ventricle ◽

Left Atrium ◽

Mitral Annulus

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Biplane ventriculography in the rat

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1986.250.1.h131 ◽

1986 ◽

Vol 250 (1) ◽

pp. H131-H136

Author(s):

J. L. Heckman ◽

L. Garvin ◽

T. Brown ◽

W. Stevenson-Smith ◽

W. P. Santamore ◽

...

Keyword(s):

Cardiac Output ◽

Left Ventricle ◽

Ejection Fraction ◽

Stroke Volume ◽

Methyl Methacrylate ◽

High Speed ◽

Water Displacement ◽

Systolic Volume ◽

End Diastolic Volume ◽

End Systolic Volume

Biplane ventriculography was performed on nine intact anesthetized rats. Images of the left ventricle large enough for analysis were obtained by placing the rats close to the radiographic tubes (direct enlargement). Sampling rates, adequate for heart rates of 500 beats/min, were obtained by filming at 500 frames/s. From the digitized silhouettes of the left ventricle the following information was obtained (means +/- SE): end-diastolic volume 0.60 +/- 0.03 ml, end-systolic volume 0.22 +/- 0.02 ml, stroke volume 0.38 +/- 0.02 ml, ejection fraction 0.63 +/- 0.02, cardiac output 118 +/- 7 ml/min, diastolic septolateral dimension 0.41 +/- 0.01 mm, diastolic anteroposterior dimension 0.40 +/- 0.01 mm, diastolic base-to-apex dimension 1.58 +/- 0.04 mm. To determine the accuracy with which the volume of the ventricle could be measured, 11 methyl methacrylate casts of the left ventricle were made. The correlation was high (r = 0.99 +/- 0.02 ml E) between the cast volumes determined by water displacement and by use of two monoplane methods (Simpson's rule of integration and the area-length method applied to the analysis of the anteroposterior films) and a biplane method (area-length). These results demonstrate that it is possible to obtain accurate dimensions and volumes of the rat left ventricle by use of high-speed ventriculography.

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Biomechanics of the Mitral Valve in Ischemic Heart Disease: Translating From the Bench to the Operating Room

ASME 2010 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2010-19422 ◽

2010 ◽

Author(s):

Muralidhar Padala ◽

Ajit P. Yoganathan

Keyword(s):

Blood Flow ◽

Mitral Valve ◽

Left Ventricle ◽

Left Atrium ◽

Mitral Annulus ◽

Normal Function ◽

Force Balance ◽

Papillary Muscles ◽

Atrioventricular Valve ◽

Main Components

The Mitral Valve (MV) is the left atrioventricular valve that controls blood flow between the left atrium and the left ventricle (Fig 1A-B). It has four main components: (i) the mitral annulus — a fibromuscular ring at the base of the left atrium and the ventricle; (ii) two collagenous planar leaflets — anterior and posterior; (iii) web of chordae and (iv) two papillary muscles (PM) that are part of the left ventricle (LV). Normal function of the mitral valve involves a delicate force balance between different components of the valve.

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Annular Height-to-Commissural Width Ratio of Annulolasty Rings In Vivo

Circulation ◽

10.1161/circulationaha.104.525485 ◽

2005 ◽

Vol 112 (9_supplement) ◽

Author(s):

Tomasz A. Timek ◽

Julie R. Glasson ◽

David T. Lai ◽

David Liang ◽

George T. Daughters ◽

...

Keyword(s):

Stress Distribution ◽

Left Ventricle ◽

Mammalian Species ◽

Mitral Annulus ◽

Width Ratio ◽

Native Valve ◽

Radiopaque Markers ◽

Duran Ring ◽

Flexible Ring

Background— A “saddle-shaped” mitral annulus with an optimal ratio between annular height and commissural diameter may reduce leaflet and chordal stress and is purported to be conserved across mammalian species. Whether annuloplasty rings maintain this relationship is unknown. Methods and Results— Twenty-three adult sheep underwent implantation of radiopaque markers on the left ventricle and mitral annulus. Eight animals underwent implantation of a Carpentier-Edwards Physio ring, 7 underwent a Medtronic Duran flexible ring, and 8 served as controls. Animals were studied with biplane videofluoroscopy 7 to 10 days postoperatively. Annular height and commissural width (CW) were determined from 3D marker coordinates, and annular height:CW ratio (AHWCR) was calculated. Annular height was similar in Control and Duran animals but significantly lower in the Physio group at end diastole (8.4±3.8, 6.7±2.3, and 3.4±0.6 mm, respectively, for Control, Duran, and Physio; ANOVA=0.005) and at end systole (14.5±6.2, 10.5±5.5, and 5.8±2.5 mm, respectively, for Control, Duran, and Physio; ANOVA=0.004). Both ring groups reduced CW significantly relative to Control. AHCWR did not differ between Control and Duran but was lower in Physio (23±11%, 24±7%, and 12±2% at end diastole and 42±17%, 37±17%, and 21±10% at end systole, respectively, for Control, Duran, and Physio, respectively; ANOVA <0.05 for both). Conclusions— Mitral annular height and AHWCR of the native valve were unchanged by a Duran ring, whereas the Physio ring led to a lower AHWCR. Theoretically, such a flexible annuloplasty ring may provide better leaflet stress distribution by maintaining normal AHWCR.

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Abstract P322: Myocardial Contraction Fraction is an Independent Predictor of Incident Adverse Cardiovascular Events; The Framingham Heart Study

Circulation ◽

10.1161/circ.129.suppl_1.p322 ◽

2014 ◽

Vol 129 (suppl_1) ◽

Author(s):

Michael L Chuang ◽

Philimon Gona ◽

Connie W Tsao ◽

Carol J Salton ◽

Warren J Manning ◽

...

Keyword(s):

Left Ventricle ◽

Stroke Volume ◽

Proportional Hazards ◽

Independent Predictor ◽

Myocardial Contraction ◽

Cox Proportional Hazards ◽

Community Dwelling ◽

Heart Study ◽

Myocardial Contraction Fraction

Introduction: Myocardial contraction fraction (MCF) is the ratio of left ventricular (LV) stroke volume to myocardial volume, and thus a measure of LV pumping capacity per unit of myocardium. We sought to determine whether MCF measured using current steady-state free precession (SSFP) cardiac magnetic resonance (CMR) sequences was an independent predictor of incident “hard” cardiovascular disease (CVD) events, defined by myocardial infarction (MI), stroke, unstable angina (UA), hospitalized heart failure (HF) or CVD death in a community dwelling cohort initially free of these CVD events. Methods: 1794 members of the Framingham Heart Study Offspring cohort (aged 65±9 years) underwent CMR between 2002-2006 using a 1.5-Tesla system with contiguous multislice SSFP cine imaging to encompass the left ventricle. MCF was determined from the cine images by a single observer blinded to participant characteristics. We tracked incident hard CVD events over median 6.5-year follow up and used Cox proportional hazards models (adjusted for age, sex, body mass index, systolic blood pressure, diabetes, dyslipidemia, smoking, treatment for hypertension) to determine hazard of hard CVD events per increment (0.10) of MCF. Results: MCF was determined in 1776 (99%) Offspring (835 men). Overall, MCF was greater in women (0.92±0.14 vs. 0.78±0.15 for men), p<0.0001. There were 60 incident hard CVD events during follow up. Incident hard events included 26 MI, 2 UA, 13 stroke, 14 hospitalized HF and 5 CVD deaths. Offspring experiencing an incident event had lower MCF (0.78±0.19 vs. 0.86±0.15 for those free of events), p=0.002. On MV-adjusted Cox proportional hazards analyses, a greater MCF was protective against hard CVD events, HR [95% confidence intervals] = 0.76 [0.63 - 0.93] per 0.10 increment of MCF. Conclusion: Over 6.5-year follow-up, greater MCF is protective against major adverse CVD events, even after adjustment for traditional CVD risk factors in a community dwelling cohort of middle-aged and older predominantly European-descended adults. Determination of MCF requires only knowledge of LV stroke volume and myocardial volume, both of which are routinely determined in a standard CMR examination of the left ventricle, and thus imposes no additional scan-time or analysis burden. While MCF may be clinically useful for prediction of risk for incident hard CVD events, its potential value in younger age groups and other ethnicities remains to be determined.

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In the Loop—Left Ventricular Pressures

Just Enough Physiology ◽

10.1093/med/9780199797790.003.0005 ◽

2011 ◽

pp. 42-47

Author(s):

James R. Munis

Keyword(s):

Heart Rate ◽

Cardiac Output ◽

Aortic Valve ◽

Left Ventricle ◽

Stroke Volume ◽

Cardiovascular System ◽

Aortic Root ◽

Left Ventricular ◽

Root Pressure ◽

The Third

We've already looked at 2 types of pressure that affect physiology (atmospheric and hydrostatic pressure). Now let's consider the third: vascular pressures that result from mechanical events in the cardiovascular system. As you already know, cardiac output can be defined as the product of heart rate times stroke volume. Heart rate is self-explanatory. Stroke volume is determined by 3 factors—preload, afterload, and inotropy—and these determinants are in turn dependent on how the left ventricle handles pressure. In a pressure-volume loop, ‘afterload’ is represented by the pressure at the end of isovolumic contraction—just when the aortic valve opens (because the ventricular pressure is now higher than aortic root pressure). These loops not only are straightforward but are easier to construct just by thinking them through, rather than by memorization.

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Quantitation of mitral annular oscillations and longitudinal “ringing” of the left ventricle: a new window into longitudinal diastolic function

Journal of Applied Physiology ◽

10.1152/japplphysiol.00844.2005 ◽

2006 ◽

Vol 100 (1) ◽

pp. 112-119 ◽

Cited By ~ 20

Author(s):

Matt M. Riordan ◽

Sándor J. Kovács

Keyword(s):

Left Ventricle ◽

Diastolic Function ◽

Elastic Strain ◽

Fluid Motion ◽

Harmonic Oscillation ◽

Mitral Annulus ◽

Left Ventricular ◽

Contour Shape ◽

Left Ventricular Stiffness ◽

Early Filling

For diastolic function (DF) quantification, transmitral flow velocity has been characterized in terms of the geometric features of a triangle (heights, widths, areas, durations) approximating the E-wave contour, whereas mitral annular velocity has only been characterized by E′-wave peak amplitude. The fact that E-waves convey global DF information, whereas annular E′-waves provide longitudinal DF information, has not been fully characterized, nor has the physiological legitimacy of combining fluid motion (E)- and tissue motion (E′)-derived measurements into routinely used indexes (E/E′) been fully elucidated. To place these Doppler echo measurements on a firmer causal, physiological, and clinical basis, we examined features of the E′-wave (and annular motion in general), including timing, amplitude, duration, and contour (shape), in kinematic terms. We derive longitudinal rather than global indexes of stiffness and relaxation of the left ventricle and explain the observed difference between E- and E′-wave durations. On the basis of the close agreement between model prediction and E′-wave contour for subjects having normal physiology, we propose damped harmonic oscillation as the proper paradigm in which to view and analyze the motion of the mitral annulus during early filling. Novel, longitudinal indexes of left ventricular stiffness, relaxation, viscosity, and stored (end-systolic) elastic strain can be determined from the E′-wave (and any subsequent waves) by modeling annular motion during early filling as damped harmonic oscillation. A subgroup exploratory analysis conducted in diabetic subjects ( n = 9) and nondiabetic controls ( n = 12) indicates that longitudinal DF indexes differentiate between these groups on the basis of longitudinal damping ( P < 0.025) and longitudinal stored elastic strain ( P < 0.005).

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P1754 Regional left ventricular longitudinal myocardial dysfunction in mitral valve prolapse could be primary

European Heart Journal - Cardiovascular Imaging ◽

10.1093/ehjci/jez319.1113 ◽

2020 ◽

Vol 21 (Supplement_1) ◽

Author(s):

P Barbier ◽

O A Annoh ◽

G Liu ◽

M Scorsin ◽

S Moriggia ◽

...

Keyword(s):

Mitral Valve ◽

Ejection Fraction ◽

Stroke Volume ◽

Myocardial Dysfunction ◽

Stroke Volume Index ◽

Volume Overload ◽

Mitral Annulus ◽

Left Ventricular ◽

Volume Index ◽

Maximum Strain

Abstract Background Regional left ventricular dysfunction in patients with mitral valve prolapse (MVP) and normal ejection fraction has been described by different Authors, and recent data point to a dysfunction (prevalently longitudinal strain) of the myocardium of the LV base secondary to dilatation of the mitral annulus. Purpose To investigate degree and extent of regional LV dysfunction and its mechanisms in patients with MVP, severe regurgitation and normal global systolic function, compared to patients with equivalent degree of regurgitation but functional etiology (FMR). Methods Speckle-tracking echocardiography was performed in 30 controls (N), and in severe primary (MVP, n= 50) or functional (FMR, n= 20) mitral regurgitation, to measure global, regional and segmental longitudinal peak systolic strain (LPSS, %), and time delay of peak maximum strain (TTPd, ms, calculated as time to peak maximum strain - time of aortic valve closure). Maximum and minimum mitral annulus diameters and area were measured with 3D echo. We also evaluated as recommended: LV end-diastolic volume index (EDVi, ml/m2), ejection fraction (EF, %), and left atrial end-systolic volume index (LAESVi, ml/m2) with 2D echo; LV stroke volume index, and non-invasive pulmonary systolic (PSP, mmHg) and diastolic pressures (PDP), mmHg) with Doppler echo. Results Age, heart rate, BSA and systolic blood pressure were similar between groups. Atrial fibrillation was present in 34% of MVP and 71% of FMR patients. LV EF was normal in MVP and reduced in FMR (43 ± 14 % vs N, p<.001). LV EDVi (MVP: 77 ± 20 ml/m2; FMR: 107 ± 35, both p<.001 vs N) and LAESVi (MVP: 91 ± 26 ml/m2; FMR: 80 ± 30, both p<.001 vs N) were similarly increased (volume overload) in MVP and FMR, as were PSP (MVP: 42 ± 23 ml/m2; FMR: 52 ± 25, both p<.001 vs N) and PDP (MVP: 16 ± 6 ml/m2; MVP: 15 ± 5, both p<.001 vs N). In FMR, LPSS was reduced globally (-12.8 ± 3.3, p<.001 vs N and MVP) and similarly at LV base, papillary and apical levels. In contrast, in MVP global (-19.4 ± 3.7%) and apical (-23.4 ± 4.5%) LPSS were normal, whereas LV base (-12.3 ± 5.8%, p=.003 vs N) and papillary (-17.1 ± 4%, p=.024 vs N) LPSS were reduced; further, LPSS reduction was localized to the anterior (-16 ± 4, p=.028 vs N), lateral (-17 ± 5, p=.006 vs N) and posterior (-16 ± 6, p=.007 vs N) segments, and was associated with an increased TTPd in the same segments in MVP but not in FMR patients. At multivariate analysis, degree and localisation of regional myocardial dysfunction in patients with MVP was not related to the prolapsing scallop, dimension of the mitral annulus, degree of volume overload or pulmonary pressures, or stroke volume index. Conclusions In patients with MVP, severe regurgitation and normal EF, there is a specific dysfunction pattern of regional LV longitudinal function which appears to be primary and not dependent on the degree of preload increase, mitral annulus dilatation, or localization of the prolapsing scallop.

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