Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0018801 (heart failure)
 72,216 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent epidemiologic studies have suggested that cardiac disease in common in diabetics and may often have a noncoronary basis. To examine the status of the left ventricle, 17 adult-onset diabetics of familial type without hypertension or obesity underwent hemodynamic study and were compared to 9 controls of similar age. Of the 17, 12 subjects had no significant occlusive lesions by coronary angiography. From this group eight without heart failure had a modest, but significant, elevation of left ventricular end-diastolic pressure. End-diastolic and stroke volumes were reduced, but ejection fraction and mean rate of fiber shortening were within normal limits. The left ventricular end-diastolic pressure/volume ratio was significantly higher than controls. Afterload increments effected a significant increase of filling pressure compared to normals without a stroke volume response, consistent with a preclinical cardiomyopathy. Four patients with prior heart failure had similar but more extensive abnormalities. None had local dyskinesia by angiography, and lactate production was not observed during pacing-induced tachycardia. Left ventricular biopsy in two patients without ventricular decompensation showed interstitial collagen deposition with relatively normal muscle cells. These findings suggest a myopathic process without ischemia. Postmortem studies were performed in 11 uncomplicated diabetics. Nine were without significant obstructive disease of the proximal coronary arteries, and the majority succumbed with cardiac failure. On left ventricular sections, none had evident luminal narrowing of the intramural vessels. All nine exhibited periodic acid-Schiff-positive material in the interstitium. Collagen accumulation was present in perivascular loci, between myofibers, or as replacement fibrosis. Multiple samples of left ventricle and septum revealed enhanced triglyceride and cholesterol concentrations, as compared to controls. Thus, a diffuse extravascular abnormality may be a basis for cardiomyopathic features in diabetes.
 ...
PMID:Evidence for cardiomyopathy in familial diabetes mellitus. 89 79

Tests conducted with adult (8--10 months) and old (26--28 months) rats brought evidence that in ageing the cardiac ejection, dp/dt max, contractility index, the ATP concentration, that of creatinophosphate, glycogen, pyruvate decline, the phosphorylation coefficient, the lactate content increase, while the level of water-soluble proteins and collagen diminishes and that of water-insoluble ones decreases. In adult rats hemodynamics and myocardial contractility change but unsignificantly on the 4--6th day after coarctation of the aorta, whereas in the old ones there occur functional and metabolic alterations in the heart that are indicative of a developing cardiac insufficiency. The age-specific differences persist also on the 14--16th day following coarctation of the aorta. During these periods the weight of the heart, the content of the myofribrillary proteins and collagen are on the rise, whereas in the old ones the weight of the heart remains unchanged and the level of water-soluble protein drops. Changes in the properties of the actomyosin complex, disruption of the calcium pump, shifts in the system of the energy generation, limitation of potential possibilities incident to the systems of protein biosynthesis in the myocardial cell, all this leads to the development of cardiac incompetence following loading in old age.
 ...
PMID:[Mechanisms of development of cardiac insufficiency in old age]. 102 32

A 14-year-old boy with an incomplete form of the Marfan syndrome developed an acute episode of severe congestive heart failure following exertion. The preoperative studies indicated a mitral insufficiency, and a floppy, thickened mitral valve was removed and replaced with a Starr-Edwards prosthesis. Microscopically, the valve showed increase in collagen with central myxomatous transformation. Seven months postoperatively the patient is doing well and has no symptoms of heart failure.
 ...
PMID:Mitral insufficiency in an incomplete form of Marfan syndrome corrected with valve replacement. 112 90

Angiotensin-converting enzyme (ACE) inhibitors are widely used for treatment of heart failure after myocardial infarction (MI). The beneficial effects consist of a combination of hemodynamic effects and interference with cardiac structural alterations. These effects are believed to depend on inhibition of angiotensin II (AII) formation and thus diminished angiotensin receptor stimulation. We administered the angiotensin II-1 (AT-1) receptor antagonist losartan during and after completion of the repair phase of an MI to investigate involvement of the AT-1 receptor in the above described effects of captopril. MI reduced cardiac output (CO) (sham 94 +/- 4 ml/min, MI 78 +/- 5 ml/min) and maximal CO (sham 154 +/- 4, MI 107 +/- 5 ml/min, respectively). Losartan (15 mg/kg/day) resulted in a rightward shift of the AII pressor dose-response curve by a factor of 32-40. Neither CO nor COVL,max was affected by losartan treatment in either phase (late treatment CO = 78 +/- 5, COVL,max = 118 +/- 9 ml/min). Although early treatment with losartan reduced cardiac hypertrophy measured as heart weight, DNA synthesis was reduced only slightly. In contrast, collagen deposition was inhibited completely. The results suggest that the effects of captopril in rats after MI are not dependent on AT-1 receptor-mediated mechanisms.
 ...
PMID:Angiotensin II receptor blockade after myocardial infarction in rats: effects on hemodynamics, myocardial DNA synthesis, and interstitial collagen content. 128 Jul 40

Left ventricular hypertrophy is a major risk factor associated with the appearance of adverse cardiovascular events. A distortion in myocardial structure, mediated by an abnormal accumulation of fibrillar collagen within the adventitia of intramyocardial coronary arteries and neighbouring interstitial spaces, alters the electrical and mechanical behaviour of the myocardium. The mechanisms responsible for the regulation of cardiac myocyte growth and collagen accumulation are therefore of considerable interest. Herein we review results of in vivo studies conducted in the authors' laboratory that addressed these issues in various experimental models. The findings indicate that in arterial hypertension myocardial hypertrophy is related to ventricular systolic pressure work. Myocardial fibrosis, on the other hand, is not related to haemodynamic workload, but rather the presence of mineralocorticoid excess relative to sodium intake and excretion. Accordingly, fibrosis can appear in both the hypertensive left and non-hypertensive right ventricles. Pharmacological probes, administered in variable doses, were used to further test and support this hypothesis. In both primary and secondary hyperaldosteronism, it was possible to prevent the pathological structural remodelling of the myocardium with an aldosterone receptor antagonist, while in unilateral renal ischaemia ACE inhibition was similarly cardioprotective. Other studies demonstrated that it was feasible to regress the fibrous tissue response and normalise diastolic stiffness. This concept of cardioreparation suggests that heart failure due to this type of structural remodelling may be reversible.
 ...
PMID:Regulatory mechanisms of myocardial hypertrophy and fibrosis: results of in vivo studies. 130 Dec 54

The authors present the pathologist's view of Uhl's anomaly based on 100 cases recorded over 31 years, 89 of which came from medico-legal autopsies following sudden unexpected death in young subjects. The anatomic diagnosis is made by macroscopic examination of the whole heart in diffuse forms (parchment heart) and from transverse sections of the mid third of the ventricle in incomplete forms, showing absence of myocardium in the juxta-septal anterior wall of the right ventricle. The wall entirely made up of adipose tissue, may retain its normal thickness. On microscopy, normal adipose tissue is observed between the epicardium and endocardium, sometimes with islets of myocardium dispersed in the subendocardial layer and with, in about half the cases, subendocardial bundles of non-hyalinized collagen without any inflammatory cellular infiltration. Other structural histopathological lesions may complicate the malformation, involving the intraseptal arterioles or the conductive system. In addition to the 89 cases of sudden and unexpected death before the age of 50 (preceded by some modification of the patient's life style in 29 cases), 11 cases were symptomatic and 5 were transplanted with a good result. The clinical diagnosis of Uhl's disease is important because of its consequences: ventricular tachycardia and possible sudden death, more rarely cardiac failure with age. Histological analysis should take into account the constant presence of adipose tissue in the right ventricle, and should only interpret excessive quantities with associated myocytic aplasia as pathological.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:[Anatomoclinical study of 100 cases of hypoplasia of the right ventricular muscle (including 89 unexpected sudden deaths). Relation with Uhl's anomaly]. 130 20

This review paper deals with recent data concerning the physiopathology of chronic heart failure. Broadly speaking, the cause of chronic heart failure is arterial hypertension and/or coronary disease. Myocardial hypertrophy is only one example of biological adjustment to the environment, and chronic heart failure, an adaptation disease, indicates its limits. Diastolic dysfunction includes 3 elements. Relaxation is slowed down by a decrease in density of Ca(2+)-ATPase in the sarcoplasmic reticulum and by a fall in Na+/Ca2+ exchange activity. The decline of tissue compliance is mainly explained by probably hormonal changes in collagen. Changes in isomyosins account for abnormalities of atrial contraction. At the beginning of mechanical overload, the fall in systolic function enables the heart to produce a normal tension. The determinant element is slowing down of intracellular calcium movements. Enlarged hearts generate arrhythmias. The origin is probably the presence of unstable calcium homeostasis.
 ...
PMID:[Chronic heart failure: biological bases of myocardial function]. 131 2

The major risk factor associated with the appearance of adverse cardiovascular events and outcome attributable to cardiovascular disease is left ventricular hypertrophy (LVH). Why this should be so resides not in the increase in myocardial mass per se, but in the disruption of myocardial structure. An abnormal accumulation of fibrillar collagen within the adventitia of intramyocardial coronary arteries and neighboring interstitial spaces represents such a distortion in structure. Furthermore, this fibrosis disrupts the electrical and mechanical behavior of the hypertrophied myocardium. Mechanisms responsible for fibrillar collagen accumulation have been examined in intact animals and cultured cardiac fibroblasts. In vivo studies indicate that myocardial fibrosis is associated with the presence of chronic mineralocorticoid excess, relative to sodium intake and excretion, not hemodynamic workload. Accordingly, fibrosis can appear in both the hypertensive, hypertrophied and nonhypertensive, nonhypertrophied ventricles. In both primary and secondary hyperaldosteronism it was possible to prevent myocardial fibrosis with an aldosterone receptor antagonist, while in unilateral renal ischemia angiotensin converting enzyme (ACE) inhibition was similarly cardioprotective. A regression in fibrous tissue and normalization of diastolic stiffness has also been possible using ACE inhibition, bringing forward the concept of cardioreparation and the notion that heart failure due to fibrosis may be reversible. In vitro studies indicate that effector hormones of the renin-angiotensin-aldosterone system stimulate fibroblast collagen synthesis. Aldosterone, in pathophysiologic concentrations, and angiotensin II, in much larger concentrations, each enhance collagen synthesis without altering the mitogenic potential of these cells. Thus, elevations in circulating aldosterone and angiotensin II, relative to sodium intake, have the potential to not only alter sodium homeostasis and vascular tonicity, but also the structure of cardiovascular tissue. Thus, myocardial fibrosis represents a structural basis for pathologic hypertrophy and ultimately accounts for the appearance of adverse cardiovascular events and outcomes.
 ...
PMID:Pathologic hypertrophy with fibrosis: the structural basis for myocardial failure. 136 63

In both men and women left ventricular hypertrophy (LVH) is the major risk factor associated with the appearance of diastolic and/or systolic myocardial failure. It is not the growth of cardiac myocytes, however, that is responsible for an abnormal structural remodeling of the hypertrophied myocardium in pathologic LVH, but instead, nonmyocyte cells whose behavior and growth are altered by chronic elevations in circulating hormones. Hormone-mediated cardiac fibroblast proliferation and/or enhanced collagen synthesis, for example, account for myocardial fibrosis. The signals mediating nonmyocyte cell involvement in LVH may also involve locally generated hormones having paracrine properties. Herein we review experimental findings pertaining to the reparative and reactive fibrosis of the myocardium seen in various forms of acquired and genetic arterial hypertension, where circulating or tissue renin-angiotensin-aldosterone systems are respectively activated. These hormonal systems determine whether myocardial structure will be altered in arterial hypertension and, accordingly, if myocardial failure ensues. The mechanisms by which these hormones lead to myocardial fibrosis remain to be elucidated and correspondingly will determine if fibrosis can be effectively prevented. At the same time, experimental strategies that regress excess collagen in LVH have been identified, but need to be developed further to determine if myocardial failure, caused by fibrosis, is indeed reversible in humans.
 ...
PMID:Myocardial fibrosis and the renin-angiotensin-aldosterone system. 138 Jun 19

The basis for impaired left ventricular function of hearts in moderate to severe stages of hypertrophy and congestive heart failure remains uncertain. At the cellular level, the mechanisms governing the movements of calcium in the myocardium are actually depressed and might at least in part account for the slowing of the maximum shortening velocity and the impaired relaxation. These alterations of membrane proteins seem particularly important in species where the slowing of Vmax cannot be a consequence of the myosin heavy chain shift. They lead to an unstable equilibrium of calcium homeostasis and to calcium overload in heart failure. On the other hand, the enhanced density and remodeling of collagen in the hypertrophied heart, which would depend on elevation in circulating aldosterone, impair myocardial stiffness with diastolic dysfunction and lead to altered pumping capacity of the heart. Disturbances of calcium metabolism and matrix collagen remodeling enhance early afterdepolarizations and arrhythmias.
 ...
PMID:Remodeling of the heart (membrane proteins and collagen) in hypertensive cardiopathy. 138 39


1 2 3 4 5 6 7 8 9 10 Next >>