Abstract 3435: Left Ventricular Hypertrophy is Resistant to Inhibition of Expression of the R403Q Alpha-Myosin Heavy Chain Cardiac Hypertrophy-Inducing Mutant Protein

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Leah Cannon ◽  
Tadeusz Marciniec ◽  
Bryony Mearns ◽  
Robert M Graham ◽  
Diane Fatkin
Keyword(s):  
Left Ventricular Hypertrophy ◽  
Ventricular Hypertrophy ◽  
Interstitial Fibrosis ◽  
Myocardial Dysfunction ◽  
Left Ventricular ◽  
Familial Hypertrophic Cardiomyopathy ◽  
Lv Function ◽  
Dependent Manner ◽  
Cardiovascular Morbidity And Mortality ◽  
Lv Mass

Left ventricular hypertrophy (LVH) develops as a compensatory response to myocardial dysfunction due to diverse causes, but is nonetheless a major risk factor for premature cardiovascular morbidity and mortality. It is thus unclear if regressing LVH is beneficial or may worsen patient outcome. To evaluate the effects of LVH regression, we developed a transgenic mouse model in which the expression of a familial hypertrophic cardiomyopathy (FHC)-inducing mutation (R403Q alpha-MHC) can be regulated in a temporal and dose-dependent manner. In this model, transgene expression can be shut off by feeding with a tetracycline analogue (doxycycline). Serial echocardiography and histology studies were performed in a cohort of mice expressing the FHC mutant (“gene-on”) and in wildtype (WT) littermates. A second cohort of WT and 403/+ mice was randomised to placebo or doxycycline (“gene off”) from 6 (Dox6) or 20 weeks (Dox20) and evaluated at 40 weeks of age. Compared to WT littermates, “gene on” 403/+ mice showed increased LV mass, LV end-diastolic diameter (LVDD) and left atrial diameter (LAD), and reduced fractional shortening (LVFS), with changes evident from 12 weeks of age. LV sections from 403/+ mice showed typical features of FHC: myofibre disarray and interstitial fibrosis. LV mass, LV function and myocardial histology were unchanged in both male and female placebo- vs Dox6 or Dox20 mice at 40 weeks (Table 1 ). Thus, consistent with the major LV thickening in FHC humans occurring in adolescence, overexpression of R403Q for only 6 weeks is sufficient to trigger the complete LVH phenotypic response. Moreover, switching off the genetic trigger for LVH in 403/+ mice at 6 weeks (prior to overt disease manifestation) or 20 weeks (established disease) does not induce regression of LVH or exacerbate contractile dysfunction. Interventions to induce LVH regression may, therefore, need to be directed at downstream factors in hypertrophic pathways. Table 1. Echo data for male WT and 403/+ mice aged 40 weeks

EVALUATION OF LEFT VENTRICULAR MASS IN THE PREHYPERTENSIVES BY ELECTROCARDIOGRAPHY AND ECHOCARDIOGRAPHY

2011 ◽  
pp. 119-125
Author(s):  
Thi Thuy Hang Nguyen
Keyword(s):  
Left Ventricular Hypertrophy ◽  
Left Ventricular Mass ◽  
Ventricular Hypertrophy ◽  
Structural Changes ◽  
Left Ventricular ◽  
Control Group ◽  
Concentric Left Ventricular Hypertrophy ◽  
Increased Risk ◽  
Lv Mass ◽  
Left Ventricular Morphology

Objective: Prehypertensive individuals are at increased risk for developing hypertension and their complication. Many studies show that 2/3 prehypertensive individuals develop hypertension after 4 years. ECG and echocardiography are the routine tests used to assess LV mass. The objective of the research to determine the percentage of change in left ventricular morphology in the ECG, echocardiography, which explore the characteristics of left ventricular structural changes by echocardiography in pre-hypertensive subjects. Materials and method: We studied a total of 50 prehypertensive, 30 males (60%) and 20 females (40%), mean age 48.20±8.47years. 50 normotensive volunteers as control participants. These subjects were examined for ECG and echocardiography. Results: In prehypertensive group, with 18% of left ventricular hypertrophy on electrocardiogram, 12% of left ventricular hypertrophy on echocardiography; in the control group, we did not find any subjects with left ventricular hypertrophy. In the group with left ventricular hypertrophy, mostly eccentric left ventricular hypertrophy (83.33%), concentric left ventricular hypertrophy is 16.67%. Restructuring of left ventricular concentric for 15.9% of subjects without left ventricular hypertrophy on echocardiography. Conclusion: There have been changed in left ventricular morphology even in prehypertensive

Gαi-biased apelin analog protects against isoproterenol-induced myocardial dysfunction in rats

2021 ◽  
Vol 320 (4) ◽  
pp. H1646-H1656
Author(s):  
David Coquerel ◽  
Eugénie Delile ◽  
Lauralyne Dumont ◽  
Frédéric Chagnon ◽  
Alexandre Murza ◽  
...  
Keyword(s):  
Cardiovascular Diseases ◽  
Left Ventricular Hypertrophy ◽  
Ventricular Hypertrophy ◽  
Myocardial Dysfunction ◽  
Negative Inotropic Effect ◽  
Left Ventricular ◽  
Inotropic Effect ◽  
Camp Production ◽  
Data Point

By using more potent Gαi-biased APJ agonists that strongly inhibit cAMP production, these data point to the negative inotropic effect of APJ-mediated Gαi signaling in the heart and highlight the potential protective impact of APJ-dependent Gαi signaling in cardiovascular diseases associated with left ventricular hypertrophy.

Abstract 12952: Global Longitudinal Strain is Simple, Effective & Sensitive Assessment of Cardiac Chamber Function in Patients With Acute-phase Myocarditis

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Shaun Khanna ◽  
Aditya Bhat ◽  
Henry H Chen ◽  
Kennith Gu ◽  
Gary Gan ◽  
...  
Keyword(s):  
Acute Phase ◽  
Longitudinal Strain ◽  
Myocardial Dysfunction ◽  
Global Longitudinal Strain ◽  
Disease Process ◽  
Left Ventricular ◽  
Lv Function ◽  
Lv Mass ◽  
Echocardiographic Parameters ◽  
Cardiac Therapy

Introduction: Myocarditis is an inflammatory disease process with growing clinical relevance in the current COVID-19 pandemic. Acute-phase myocarditis is known to result in subclinical changes in left ventricular (LV) function despite normal LV ejection fraction (LVEF), as assessed by myocardial deformation indices. The presence of right ventricular (RV) and left atrial (LA) subclinical dysfunction however has not been well described in current literature. Hypothesis: Myocarditis patients have subclinical impairment of LV, RV and LA function as assessed by global longitudinal strain (GLS) on speckle tracking echocardiography. Methods: Consecutive patients with clinical diagnosis of myocarditis admitted to our institution during 2013-2018 were assessed (n=76). Patients who did not meet appropriate diagnostic criteria (n=14), had impaired LVEF or prior cardiac disease (n=8) or poor transthoracic echocardiogram images (n=14) were excluded from analysis. Clinical and echocardiographic parameters were compared to age- , gender- and risk factor- matched controls. GLS was performed by two independent observers using vendor independent software (TomTec Arena, Germany v4.6). Results: The final cohort consisted 40 patients with myocarditis (age 44.3±16.7, 60% male) and 40 matched controls (44.5±16.6, 60% male). No significant differences in baseline clinical characteristics were observed between groups. No differences in LVEF, indexed LV mass, RV fractional area change, indexed LA volume or TR pressure gradient (p>0.05 for all) were demonstrated between the two groups. Patients with myocarditis had a lower mean LV strain (GLS%: -16.4±2.9 vs -19.7±2.7, p=0.0001), a lower mean RV Free Wall Strain (FWS) (GLS%: -22.1±4.1 vs -26.2±6.9, p=0.03) and a lower mean LA reservoir strain (GLS%: 27.5±4.6 vs. 33.7±6.3, p<0.0001) when compared to controls. Conclusions: Our results demonstrate the presence of significant subclinical global myocardial dysfunction despite normal traditional echocardiographic indices, in patients with acute-phase myocarditis. Routine assessment of GLS may identify such patients for early targeted cardiac therapy.

scholarly journals Left ventricular hypertrophy in patients treated with regular hemodialyses

2008 ◽  
Vol 61 (7-8) ◽  
pp. 369-374 ◽  
Author(s):  
Dejan Petrovic ◽  
Biljana Stojimirovic
Keyword(s):  
Risk Factors ◽  
Left Ventricle ◽  
Left Ventricular Hypertrophy ◽  
Ventricular Hypertrophy ◽  
Pressure Overload ◽  
Left Ventricular ◽  
Cardiovascular Morbidity ◽  
Morbidity And Mortality ◽  
Concentric Hypertrophy ◽  
Cardiovascular Morbidity And Mortality

Left ventricular hypertrophy is the main risk factor for development of cardiovascular morbidity and mortality in patients on hemodialysis. Left ventricular hypertrophy is found in 75% of the patients treated with hemodialysis. Risk factors for left ventricular hypertrophy in patients on hemodialysis include: blood flow through arterial-venous fistula, anemia, hypertension, increased extracellular fluid volume, oxidative stress, microinflammation, hyperhomocysteinemia, secondary hyperpara- thyroidism, and disturbed calcium and phosphate homeostasis. Left ventricular pressure overload leads to parallel placement of new sarcomeres and development of concentric hypertrophy of left ventricle. Left ventricular hypertrophy advances in two stages. In the stage of adaptation, left ventricular hypertrophy occurs as a response to increased tension stress of the left ventricular wall and its action is protective. When volume and pressure overload the left ventricle chronically and without control, adaptive hypertrophy becomes maladaptive hypertrophy of the left ventricle, where myocytes are lost, systolic function is deranged and heart insufficiency is developed. Left ventricular mass index-LVMi greater than 131 g/m2 in men and greater than 100 g/m2 in women, and relative wall thickness of the left ventricle above 0.45 indicate concentric hypertrophy of the left ventricle. Eccentric hypertrophy of the left ventricle is defined echocardiographically as LVMi above 131 g/m2 in men and greater than 100 g/m2 in women, with RWT ?0.45. Identification of patients with increased risk for development of left ventricular hypertrophy and application of appropriate therapy to attain target values of risk factors lead to regression of left ventricular hypertrophy, reduced cardiovascular morbidity and mortality rates and improved quality of life in patients treated with regular hemodialyses.

Cardiac response to pressure overload in 129S1/SvImJ and C57BL/6J mice: temporal- and background-dependent development of concentric left ventricular hypertrophy

2007 ◽  
Vol 292 (5) ◽  
pp. H2119-H2130 ◽  
Author(s):  
Cordelia J. Barrick ◽  
Mauricio Rojas ◽  
Robert Schoonhoven ◽  
Susan S. Smyth ◽  
David W. Threadgill
Keyword(s):  
Heart Failure ◽  
Left Ventricular Hypertrophy ◽  
Ventricular Hypertrophy ◽  
Pressure Overload ◽  
Left Ventricular ◽  
Cardiac Response ◽  
Dependent Manner ◽  
Geometric Patterns ◽  
Concentric Hypertrophy ◽  
Eccentric Hypertrophy

Left ventricular hypertrophy (LVH), a risk factor for cardiovascular morbidity and mortality, is commonly caused by essential hypertension. Three geometric patterns of LVH can be induced by hypertension: concentric remodeling, concentric hypertrophy, and eccentric hypertrophy. Clinical studies suggest that different underlying etiologies, genetic modifiers, and risk of mortality are associated with LVH geometric patterns. Since pressure overload-induced LVH can be modeled experimentally using transverse aortic constriction (TAC) and since C57BL/6J (B6) and 129S1/SvImJ (129S1) strains, which have different baseline cardiovascular phenotypes, are commonly used, we conducted serial echocardiographic studies to assess cardiac function up to 8 wk of post-TAC in male B6, 129S1, and B6129F1 (F1) mice. B6 mice had an earlier onset and more pronounced impairment in contractile function, with corresponding left and right ventricular dilatation, fibrosis, change in expression of hypertrophy marker, and increased liver weights at 5 wk of post-TAC. These observations suggest that B6 mice had eccentric hypertrophy with systolic dysfunction and right-sided heart failure. In contrast, we found that 129S1 and F1 mice delayed transition to decompensated heart failure, with 129S1 mice exhibiting preserved systolic function until 8 wk of post-TAC and relatively mild alterations in histology and markers of hypertrophy at 5 wk post-TAC. Consistent with concentric hypertrophy, our results show that these strains manifest different cardiac responses to pressure overload in a time-dependent manner and that genetic susceptibility to initial concentric hypertrophy is dominant to eccentric hypertrophy. These results also imply that genetic background differences can complicate interpretation of TAC studies when using mixed genetic backgrounds.

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