Left Ventricular Filling in Ischemic and Hypertrophic Heart Disease

Bonow, Robert O.

doi:10.1007/978-1-4615-6832-2_23

Cited by 7 publications

(3 citation statements)

References 48 publications

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“…A possible explanation for this discrepancy would be that the relationship between the slack length of isolated myocytes and LV diastolic dimension of hearts in situ is different in TG versus WT mice, due to differences in other factors that are thought to modulate LV diastolic dimension. These include ␤-adrenergic tone, coronary blood flow, myocyte relaxation in vivo, diastolic filling pressure, LV compliance, and/or regional asynchrony of LV relaxation (4). Nevertheless, we cannot rule out the possibility that a subpopulation of myocytes exhibiting extreme structural remodeling was more prone to dam- age during the enzymatic dispersion and, therefore, contributed to changes of the LV diastolic dimension in situ but was underrepresented in the morphometric assessments in isolated myocytes.…”

Section: H965mentioning

confidence: 98%

Morphological and functional changes in cardiac myocytes isolated from mice overexpressing TNF-α

Janczewski

Kadokami

Lemster

et al. 2003

American Journal of Physiology-Heart and Circulatory Physiology

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Transgenic (TG) TNF1.6 mice, which cardiac specifically overexpress tumor necrosis factor-alpha (TNF-alpha), exhibit heart failure (HF) and increased mortality, which is markedly higher in young (<20 wk) males (TG-M) than females (TG-F). HF in this model may be partly caused by remodeling of the extracellular matrix and/or structure/function alterations at the single myocyte level. We studied left ventricular (LV) structure and function using echocardiography and LV myocyte morphometry, contractile function, and intracellular Ca(2+) (Ca(i)(2+)) handling using cell edge detection and fura 2 fluorescence, respectively, in 12-wk-old TG-M and TG-F mice and their wild-type (WT) littermates. TG-F mice showed LV hypertrophy without dilatation and only a small reduction of basal fractional shortening (FS) and response to isoproterenol (Iso). TG-M mice showed a large LV dilatation, higher mRNA levels of beta-myosin heavy chain and atrial natriuretic factor versus TG-F mice, reduced FS relative to both WT and TG-F mice, and minimal response to Iso. TG-F and TG-M myocytes were similarly elongated (by approximately 20%). The amplitude of Ca(i)(2+) transients and contractions and the response to Iso were comparable in WT and TG-F myocytes, whereas the time to 50% decline (TD(50%)) of the Ca(i)(2+) transient, an index of the rate of sarcoplasmic reticulum Ca(2+) uptake, was prolonged in TG-F myocytes. In TG-M myocytes, the amplitudes of Ca(i)(2+) transients and contractions were reduced, TD(50%) of the Ca(i)(2+) transient was prolonged, and the inotropic effect of Iso on Ca(i)(2+) transients was reduced approximately twofold versus WT myocytes. Protein expression of sarco(endo)plasmic reticulum Ca(2+)-ATPase 2 and phospholamban was unaltered in TG versus WT hearts, suggesting functional origins of impaired Ca(2+) handling in the former. These results indicate that cardiac-specific overexpression of TNF-alpha induces myocyte hypertrophy and gender-dependent alterations in Ca(i)(2+) handling and contractile function, which may at least partly account for changes in LV geometry and in vivo cardiac function in this model.

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Section: H965mentioning

confidence: 98%

Morphological and functional changes in cardiac myocytes isolated from mice overexpressing TNF-α

Janczewski

Kadokami

Lemster

et al. 2003

American Journal of Physiology-Heart and Circulatory Physiology

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“…6) Thus, the present method appears to be capable of constructing regional time-density curves which allow assessment of regional left ventricular performance noninvasively without the use of contrast medium.…”

Section: Patientsmentioning

confidence: 97%

New Noninvasive Assessment of Regional Left Ventricular Function by Digital Subtraction Angiography without the Use of Contrast Medium.

et al. 1991

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SUMMARYWe have developed a new noninvasive method to evaluate regional left ventricular (LV) function by digital subtraction angiography (DSA) without the use of contrast medium.DSA images of the left ventricle with and without contrast medium were obtained from 35 patients with anterior myocardial infarction (MI) and from 35 control subjects.Using an image-processing computer, regional LV time-density curves were constructed for one cardiac cycle. Regional LV time-density curves obtained from DSA without the use of contrast medium presented a pattern similar to those from intravenous DSA. The amplitude of regional LV time-density curves in patients with MI decreased along with increasing severity of regional wall motion abnormality assessed by conventional left ventriculography.In attempting semi-quantitative evaluation by DSA without the use of contrast medium, the regional wall motion index (RWI) in the 6 segments of the left ventricle was calculated by normalizing segmental density changes to the maximal segmental density changes. When compared with control subjects, patients with MI have significantly lower RWIs in the anterolateral and apical regions. RWI showed a good correlation with the regional ejection fraction (REF) obtained from intravenous contrast DSA (r=0.83).RWI decreased with increasing severity of regional wall motion abnormality by qualitative analysis in conventional left ventriculography, being consistent with REF.The diagnostic accuracy of RWI therefore seemed to be comparable to that of REF derived from intravenous contrast DSA. These results indicate that computerized analysis of DSA without the use of contrast medium

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“…In patients with ischemia or hypertrophy, the rate and completeness of the relaxation process can modify the diastolic filling phase. 78 In occasional patients with severe hypertrophy, the left ventricular waveform shows a continuous decay of pressure into late diastole at a time when ventricular filling is occurring.B Such patients provide evidence of the impact that impaired ventricular relaxation may have on the period of diastolic filling.…”

Section: Diastolic Relaxation and Fillingmentioning

confidence: 99%

The Physiological Basis of Left Ventricular Diastolic Dysfunction

Apstein

Lorell

1988

J Cardiac Surgery

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Overall cardiac pump function requires adequate ventricular diastolic filling as well as normal systolic ejection. Abnormalities of the rate or extent of myocardial relaxation (diastolic dysfunction) have been described in a large variety of clinical conditions, including hypertrophy, ischemia, and after cardiac surgery. Diastolic and systolic dysfunction can be readily distinguished by analysis of pressure volume loops and utilization of echocardiography or nuclear cardiology gated blood pool scans. The mechanisms by which diastolic dysfunction can occur may be structural (hypertrophy, fibrosis) or dynamic (hypoxia, ischemia, alteration of diastolic cytosolic calcium levels). Hypertrophied myocardium is particularly susceptible to diastolic dysfunction by virtue of both structural changes (increased LV mass and interstitial fibrosis) and greater susceptibility to develop impaired myocardial relaxation during hypoxia or ischemia than nonhypertrophied myocardium.

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Left Ventricular Filling in Ischemic and Hypertrophic Heart Disease

Cited by 7 publications

References 48 publications

Morphological and functional changes in cardiac myocytes isolated from mice overexpressing TNF-α

Morphological and functional changes in cardiac myocytes isolated from mice overexpressing TNF-α

New Noninvasive Assessment of Regional Left Ventricular Function by Digital Subtraction Angiography without the Use of Contrast Medium.

The Physiological Basis of Left Ventricular Diastolic Dysfunction

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