ESPVR of in situ rat left ventricle  shows contractility-dependent curvilinearity

We developed a miniaturized conductance catheter for in situ rat left ventricular (LV) volumetry. After the validation study of the conductance volumetry in 11 rats, we characterized the end-systolic pressure-volume relationship (ESPVR) in 24 sinoaortic-denervated, vagotomized and urethan-anesthetized rats. Stroke volume (SV) measured with the conductance catheter correlated closely with that measured by electromagnetic flowmetry ( r > 0.95). No significant difference was found between the in situ LV end-diastolic volumes measured by conductance volumetry and postmortem morphometry; a linear regression analysis indicated that the correlation coefficient was 0.934, that the slope was not significantly different from 1, and that the intercept was not significantly different from 0. During cardiac sympathotonic conditions, the ESPVR was curvilinear. The estimated slope of ESPVR (end-systolic elastance, E es) by quadratic curve fitting at end-systolic pressure of 100 mmHg was 2,647 ± 846 mmHg/ml. Bilateral cervical and stellate ganglionectomy depressed contractility and made the ESPVR linear; a quadratic equation did not improve the fit. E es was 946 ± 55 mmHg/ml with the volume-axis ( V 0) intercept of 0.076 ± 0.007 ml. Administration of propranolol (1 mg/kg) further reduced E es (573 ± 61 mmHg/ml, P < 0.001) and increased V 0 slightly (0.091 ± 0.011 ml). We conclude that the conductance catheter method is useful for the assessment of the ESPVR of the in situ rat left ventricle and that the ESPVR displays contractility-dependent curvilinearity.

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Effects Of Milrinone On Left Ventricular End-Systolic Pressure-Volume Relationship Of Rat Hearts In Situ

Clinical and Experimental Pharmacology and Physiology ◽

10.1046/j.1440-1681.2001.03512.x ◽

2001 ◽

Vol 28 (9) ◽

pp. 737-742 ◽

Cited By ~ 16

Author(s):

Takashi Kishi ◽

Kazuyoshi Nakahashi ◽

Haruo Ito ◽

Shigeki Taniguchi ◽

Miyako Takaki

Keyword(s):

Systolic Pressure ◽

Left Ventricular ◽

Rat Hearts ◽

Volume Relationship ◽

Pressure Volume Relationship ◽

Relationship Of

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Measurement of left ventricular mass in rats using electrocardiogram-gated magnetic resonance imaging

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1990.258.4.h1181 ◽

1990 ◽

Vol 258 (4) ◽

pp. H1181-H1186 ◽

Cited By ~ 3

Author(s):

W. J. Manning ◽

J. Y. Wei ◽

E. T. Fossel ◽

D. Burstein

Keyword(s):

Magnetic Resonance ◽

Left Ventricle ◽

Mr Imaging ◽

Linear Regression Analysis ◽

Left Ventricular ◽

Sprague Dawley ◽

Lv Mass ◽

Significant Difference ◽

Aortic Leaflet

To evaluate the ability of electrocardiogram (ECG)-gated magnetic resonance (MR) imaging to assess in vivo left ventricular (LV) mass in the rat, we studied 20 healthy adult Sprague-Dawley and Fischer 344 rats and 8 additional rats that underwent scanning after induction of volume overload by aortic leaflet disruption. ECG-gated spin-echo pulse sequences were used to acquire a series of 1-mm thick modified short-axis images of the left ventricle. The area enclosed by the endocardial and epicardial borders of the left ventricle was multiplied by the interslice distance and specific gravity of myocardium to obtain calculated slice mass. Total LV mass was obtained by summing the individual slices. The calculated value for LV mass was then compared with the LV mass as determined at postmortem examination. Linear regression analysis showed an excellent correlation of MR-estimated mass (x) with autopsy-measured LV mass (y) (y = 0.90x + 65, r = 0.98). For this method intraobserved and interobserver slice correlations were 0.97 and 0.96, respectively. There was no significant difference in LV mass as determined from a series of diastolic vs. systolic images in a subset of six animals. Over a mean of 6.5 wk of observation, LV mass increased by 40% in the animals subjected to aortic leaflet disruption. These results demonstrate that MR imaging is highly accurate for the non-invasive in vivo assessment of LV mass in the adult rat.

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Effects of hypertonic saline and dextran 70 on cardiac functions after burns

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1995.268.2.h856 ◽

1995 ◽

Vol 268 (2) ◽

pp. H856-H864 ◽

Cited By ~ 2

Author(s):

K. Suzuki ◽

R. Ogino ◽

M. Nishina ◽

A. Kohama

Keyword(s):

Hypertonic Saline ◽

Cardiac Contractility ◽

Systolic Pressure ◽

Left Ventricular ◽

Sudden Increase ◽

Stroke Work ◽

End Diastolic Volume ◽

Significant Difference ◽

Volume Relationship ◽

Pressure Volume Relationship

The effects of hypertonic saline-dextran (HSD) on cardiac contractility and hemodynamics after burns were studied in anesthetized animals with full-thickness 50% total body surface area burns that were resuscitated with HSD or lactated Ringer solution (LR) alone. No significant difference in cardiac contractility during 6 h postburn was observed between the two groups, as assessed by the end-systolic pressure-volume relationship and the stroke work-end-diastolic volume relationship. An additional bolus of HSD at 6 h postburn caused no significant changes in the end-systolic pressure-volume relationship and stroke work-end-diastolic volume relationship in the burned and sham-burned animals, both of which were resuscitated with HSD. Ten minutes of hemodynamic changes following HSD infusion at 30 min postburn revealed a sudden increase in stroke volume with biphasic responses in left ventricular systolic pressure, which first decreased, then increased, and finally returned to the pre-HSD value. End-diastolic volume was maintained at approximately 110% of the pre-HSD value during this period. We concluded that HSD does not enhance cardiac contractility after severe burns but does produce direct effects on postburn circulation to reduce afterload and augment preload, resulting in a short-lived increase in cardiac output.

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Left ventricular volumetric conductance catheter for rats

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1996.270.4.h1509 ◽

1996 ◽

Vol 270 (4) ◽

pp. H1509-H1514 ◽

Cited By ~ 18

Author(s):

H. Ito ◽

M. Takaki ◽

H. Yamaguchi ◽

H. Tachibana ◽

H. Suga

Keyword(s):

Systolic Pressure ◽

Left Ventricular ◽

Conductance Catheter ◽

Inferior Vena Caval ◽

Essential Parameter ◽

Cardiac Pump Function ◽

Catheter Tip ◽

Electromagnetic Flow Probe ◽

Lv Volume

Left ventricular (LV) volume (V) is an essential parameter for assessment of the cardiac pump function. Measurement of LVV in situ by a conductance catheter method has been widely used in dogs and humans but not yet in small experimental animals such as rats. We instituted a miniaturized six-electrode conductance catheter (3-F) for rat LVV measurement and its signal processing apparatus. We compared stroke volumes (SVs) simultaneously measured with this conductance catheter introduced into the LV through the apex and an electromagnetic flow probe placed on the ascending aorta during gradual decreases in LVV by an inferior vena caval occlusion. A high and linear correlation (r = 0.982) was obtained between these differently measured by SVs pooled from six rats. In another group of three rats, LV pressure was simultaneously measured with a 3-F catheter-tip micromanometer introduced into the LV through the apex. We obtained the slope of the end-systolic pressure-volume (P-V) relationship (Emax) by a gradual ascending aortic occlusion. After administration of propranolol, Emax obviously decreased with no change in volume intercept of the P-V relationship. The conductance volumetry proved to be useful in rats.

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Myocardial deformation in patients with a single left ventricle using 2D cardiovascular magnetic resonance feature tracking: a case–control study

The International Journal of Cardiovascular Imaging ◽

10.1007/s10554-021-02230-2 ◽

2021 ◽

Author(s):

Fabian Strodka ◽

Jana Logoteta ◽

Roman Schuwerk ◽

Mona Salehi Ravesh ◽

Dominik Daniel Gabbert ◽

...

Keyword(s):

Cardiovascular Magnetic Resonance ◽

Magnetic Resonance ◽

Left Ventricle ◽

Feature Tracking ◽

Systolic Function ◽

Radial Strain ◽

Left Ventricular ◽

Lv Function ◽

Significant Difference ◽

Lv Volumes

AbstractVentricular dysfunction is a well-known complication in single ventricle patients in Fontan circulation. As studies exclusively examining patients with a single left ventricle (SLV) are sparse, we assessed left ventricular (LV) function in SLV patients by using 2D-cardiovascular magnetic resonance (CMR) feature tracking (2D-CMR-FT) and 2D-speckle tracking echocardiography (2D-STE). 54 SLV patients (11.4, 3.1–38.1 years) and 35 age-matched controls (12.3, 6.3–25.8 years) were included. LV global longitudinal, circumferential and radial strain (GLS, GCS, GRS) and strain rate (GLSR, GCSR, GRSR) were measured using 2D-CMR-FT. LV volumes, ejection fraction (LVEF) and mass were determined from short axis images. 2D-STE was applied in patients to measure peak systolic GLS and GLSR. In a subgroup analysis, we compared double inlet left ventricle (DILV) with tricuspid atresia (TA) patients. The population consisted of 19 DILV patients, 24 TA patients and 11 patients with diverse diagnoses. 52 patients were in NYHA class I and 2 patients were in class II. Most SLV patients had a normal systolic function but median LVEF in patients was lower compared to controls (55.6% vs. 61.2%, p = 0.0001). 2D-CMR-FT demonstrated reduced GLS, GCS and GCSR values in patients compared to controls. LVEF correlated with GS values in patients (p < 0.05). There was no significant difference between GLS values from 2D-CMR-FT and 2D-STE in the patient group. LVEF, LV volumes, GS and GSR (from 2D-CMR-FT) were not significantly different between DILV and TA patients. Although most SLV patients had a preserved EF derived by CMR, our results suggest that, LV deformation and function may behave differently in SLV patients compared to healthy subjects.

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Rhythm effects on contractility of the beating isovolumic left ventricle

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1960.199.6.1115 ◽

1960 ◽

Vol 199 (6) ◽

pp. 1115-1120 ◽

Cited By ~ 60

Author(s):

B. Lendrum ◽

H. Feinberg ◽

E. Boyd ◽

L. N. Katz

Keyword(s):

Heart Rate ◽

Left Ventricle ◽

Systolic Pressure ◽

Ventricular Volume ◽

Contractile Force ◽

Postextrasystolic Potentiation ◽

Pressure Development ◽

Induced Changes ◽

Electrical Alternans

Variation in contractile force of the isovolumic contracting left ventricle of the dog was studied in open-chested in situ hearts. The electrocardiogram and intraventricular pressures were recorded at various heart volumes. Spontaneous changes in heart rate and rhythm occurred at all volumes. Isovolumic systolic pressure development (contractile force) varied with rate and rhythm. Contractile force increased with heart rate (treppe) regardless of pacemaker origin. When a premature beat was followed by a compensatory pause, the premature beat showed a decrease and the next beat an increase in contractile force (postextrasystolic potentiation). The magnitude of the changes varied directly with the prematurity of the beat. Mechanical alternans was observed with electrical alternans, despite the absence of significant volume change. Rate-induced changes, postextrasystolic potentiation and mechanical alternans were additive when they occurred simultaneously. For practical purposes, ventricular volume (filling), hence muscle fiber length, remained constant during these rate and rhythm change, therefore could not affect the strength of contraction. Contractile force changes directly attributable to rate and rhythm changes do, therefore, occur in the intact mammalian heart.

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Ventricular systolic interdependence: volume elastance model in isolated canine hearts

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1987.253.6.h1381 ◽

1987 ◽

Vol 253 (6) ◽

pp. H1381-H1390 ◽

Cited By ~ 18

Author(s):

W. L. Maughan ◽

K. Sunagawa ◽

K. Sagawa

Keyword(s):

Left Ventricle ◽

Right Ventricle ◽

Cross Talk ◽

Systolic Pressure ◽

Left Ventricular ◽

Ventricular Free Wall ◽

Free Wall ◽

Right Ventricular Free Wall ◽

Systolic Volume ◽

The Right

To analyze the interaction between the right and left ventricle, we developed a model that consists of three functional elastic compartments (left ventricular free wall, septal, and right ventricular free wall compartments). Using 10 isolated blood-perfused canine hearts, we determined the end-systolic volume elastance of each of these three compartments. The functional septum was by far stiffer for either direction [47.2 +/- 7.2 (SE) mmHg/ml when pushed from left ventricle and 44.6 +/- 6.8 when pushed from right ventricle] than ventricular free walls [6.8 +/- 0.9 mmHg/ml for left ventricle and 2.9 +/- 0.2 for right ventricle]. The model prediction that right-to-left ventricular interaction (GRL) would be about twice as large as left-to-right interaction (GLR) was tested by direct measurement of changes in isovolumic peak pressure in one ventricle while the systolic pressure of the contralateral ventricle was varied. GRL thus measured was about twice GLR (0.146 +/- 0.003 vs. 0.08 +/- 0.001). In a separate protocol the end-systolic pressure-volume relationship (ESPVR) of each ventricle was measured while the contralateral ventricle was alternatively empty and while systolic pressure was maintained at a fixed value. The cross-talk gain was derived by dividing the amount of upward shift of the ESPVR by the systolic pressure difference in the other ventricle. Again GRL measured about twice GLR (0.126 +/- 0.002 vs. 0.065 +/- 0.008). There was no statistical difference between the gains determined by each of the three methods (predicted from the compartment elastances, measured directly, or calculated from shifts in the ESPVR). We conclude that systolic cross-talk gain was twice as large from right to left as from left to right and that the three-compartment volume elastance model is a powerful concept in interpreting ventricular cross talk.

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Inotropic effects of ejection are myocardial properties

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1994.266.3.h1202 ◽

1994 ◽

Vol 266 (3) ◽

pp. H1202-H1213 ◽

Cited By ~ 13

Author(s):

P. P. De Tombe ◽

W. C. Little

Keyword(s):

Systolic Pressure ◽

Left Ventricular ◽

Negative Effects ◽

Inotropic Effects ◽

Contraction Duration ◽

Loading System ◽

Positive Effect ◽

Isolated Rat

Recent studies in isolated and in vivo canine hearts have suggested that the left ventricular end-systolic pressure (LVPes) of ejecting beats is the net result of a balance between positive and negative effects of ejection. At present, it is unknown whether these ejection effects are merely a ventricular chamber property or represent a fundamental myocardial property. Accordingly, we examined the effects of ejection in eight isolated rat cardiac trabeculae at the sarcomere level. We approximated in situ sarcomere shortening patterns using an iterative computer loading system. Six isovolumic contractions were compared with four ejecting contractions. The superfusing solution contained either 0.7 mM Ca2+ or 0.65 mM Sr2+ plus 0.15 mM Ca2+. With Ca2+, simulated LVPes ("LVP"es) of ejecting contractions was significantly lower than isovolumic "LVP"es (-5.3 +/- 5.6%), whereas with Sr2+, ejecting "LVP"es was significantly higher than isovolumic "LVP"es (+4.5 +/- 7.5%). Contraction duration and time to end systole were markedly prolonged in ejecting vs. isovolumic contractions with either Ca2+ or Sr2+. As a consequence, comparison of simulated LVP between ejecting and isovolumic beats throughout the contraction, i.e., at the same simulated LVV and time, revealed only a positive effect of ejection with either Ca2+ (+18.8 +/- 5.5%) or Sr2+ (+23.4 +/-9.3%). We conclude that both positive and negative effects of ejection are basic myocardial properties.

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An Echocardiographic Evaluation of Dilated Cardiomyopathy in a Tertiary Care Hospital

Journal of Nepal Medical Association ◽

10.31729/jnma.3992 ◽

2019 ◽

Vol 57 (215) ◽

Author(s):

Raj Kumar Thapa ◽

Kanchan K.C ◽

Rishi Khatri ◽

Devendra Khatri ◽

Rajeeb Kumar Deo ◽

...

Keyword(s):

Heart Failure ◽

Congestive Heart Failure ◽

Left Ventricle ◽

Ejection Fraction ◽

Dilated Cardiomyopathy ◽

Tertiary Care ◽

Left Ventricular ◽

Care Hospital ◽

Echocardiographic Evaluation ◽

Significant Difference

Introduction: Cardiomyopathies are diseases of heart muscle that may originate from genetic defects, cardiac myocyte injury or infiltration of myocardial tissues. Dilated cardiomyopathy is the most common phenotype and is often a final common pathway of numerous cardiac insults. Mostly it remains unknown in the absence of echocardiography, histopathology and genetic evaluation. Though common it is underdiagnosed with not much of data available in our setup.Methods: This study was analytical cross-sectional study of hospital data on Echocardiographic findings in 65 patients of DCM visiting cardiology unit for Echocardiographic evaluation from 1st of February to 31st July 2018 for the period of six months in Shree Birendra Hospital, a tertiary care military hospital at Chhauni, Kathmandu. Pediatric age group patients and those who refused to give consent were excluded. Data obtained were entered in Microsoft Excel 2010 and analyzed by IBM SPSS 21.Results: Among 65 patients enrolled 40 (61%) were male and 25 (39%) female with male to female ratio of 1.6:1. Elderly people (61-75 years) with an average age of 65 were commonly involved and they presented mostly with congestive heart failure, 32 (49%). Echocardiographic evaluation showed 36 (55%) with mildly dilated Left Ventricle (5.6-6.0cm). Majority had reduced Left ventricular systolic function with an average Ejection fraction (EF) of 39.6%. No significant difference between male and female with the average EF% (P=0.990) and there was no significant relation between age and average EF% (P=0.091).Conclusions: Dilated Cardiomyopathy is the commonest cardiomyopathy phenotype mostly presenting with congestive heart failure. It is often underdiagnosed in our part of the world, however echocardiography will easily detect the condition. Keywords: dilated cardiomyopathy; echocardiography; ejection fraction; left ventricle.

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