Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0264733 (ventricular dilatation)
 2,163 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An important antecedent to the development of late congestive heart failure is left ventricular dilatation and remodeling following myocardial infarction, which occurs in 30-40% of acute anterior transmural infarcts. Dilatation and remodeling commence within the first 24 hours following myocardial infarction and may be steadily progressive over months to years. Both the infarcted and uninfarcted regions of the myocardium are equally involved in the process. The remodeling process comprises left ventricular wall thinning (mainly due to cell slippage), chamber dilatation, and compensatory hypertrophy of the uninfarcted segment of the myocardium. The hypertrophy may initially be physiologic but may ultimately become a pathologic process, and thereby contribute to pump dysfunction. The possible reasons why the ventricular hypertrophy may ultimately be dysfunctional include alterations in local architecture and their sequelae alone or in concert with local changes in the beta-adrenergic, alpha-adrenergic, or renin angiotensin systems. At the present time, there are encouraging data to suggest that nitroglycerin, or the angiotensin converting enzyme inhibitor captopril, may ameliorate this process.
 ...
PMID:Left ventricular dilatation and failure post-myocardial infarction: pathophysiology and possible pharmacologic interventions. 214 59

Challenge to a new therapeutic principle to treat heart failure is to ameliorate or eliminate symptoms, decelerate progression of the disease and reduce mortality. However, to begin, one would request improvement of objective hemodynamic parameters. Angiotensin converting enzyme (ACE) inhibitors may have acute and chronic, global and regional effects. ACE inhibitors acutely and chronically reduce pre- and afterload without reflex tachycardia. They lower myocardial oxygen consumption and improve the relation of coronary blood flow to myocardial oxygen consumption. Cerebral and renal blood flow generally are beneficially influenced if the blood pressure is not lowered too much. Left ventricular dilatation following extensive myocardial infarction which is prognostically unfavourable, may be retarded or prevented by ACE-inhibitors. It is not yet clear whether mortality may thus be reduced as in patients with severe heart failure. Large multicenter studies currently address this question. It is unclear as well whether the effects of ACE-inhibitors are exclusively due to a reduction of circulating angiotensin II. Most likely, interference is of major importance with local renin-angiotensin systems, other hormone systems and the central and peripheral nervous system.
 ...
PMID:[Modification of hemodynamics by angiotensin converting enzyme inhibitors in heart failure]. 219 16

The hemodynamic and hormonal changes produced by adriamycin-induced cardiomyopathic congestive heart failure in rabbits were studied. Adriamycin cardiomyopathy in rabbits led to ventricular dilatation, pleural and pericardial effusions, hepatic congestion, and ascites. These pathological changes were associated with the maintenance of a normal blood pressure but a lowered cardiac output and increased total peripheral resistance. Plasma renin activity and plasma norepinephrine were increased twofold in rabbits with congestive cardiac failure. However, plasma vasopressin and osmolality were normal, whereas an increased vascular sensitivity to the infusion of exogenous vasopressin was demonstrated. Despite the normal levels of plasma vasopressin, administration of a specific vascular vasopressin antagonist led to a fall in blood pressure, a significant increase in cardiac output, and a decrease in total peripheral resistance. No such hemodynamic changes occurred on infusing normal rabbits with the vascular vasopressin antagonist, nor did any significant hemodynamic changes occur on injecting vehicle in rabbits with heart failure. These results suggest that in adriamycin-induced cardiomyopathic heart failure in rabbits, there is activation of the renin-angiotensin system and the sympathetic nervous system together with an increased sensitivity to vasopressin. These three hormonal systems help to maintain blood pressure by increasing total peripheral resistance in this experimental model of heart failure.
 ...
PMID:Role of vasopressin in experimental congestive cardiac failure. 243 82

1. The circulating and tissue renin-angiotensin systems (RAS) contribute importantly to cardiovascular homeostasis. Systemic and/or local activation of the RAS is seen in many pathological conditions of the cardiovascular system (e.g. hypertension and congestive heart failure). Increased angiotensin production participates in the pathophysiology of these and other disease states. Accordingly, inhibitors of the renin angiotensin system have a broad spectrum of therapeutic efficacy. 2. Angiotensin-converting enzyme (ACE) inhibitors are effective antihypertensive agents that do not adversely affect serum lipid levels. In addition, they reduce left ventricular hypertrophy. 3. ACE inhibitors cause coronary vasodilation and reduce ventricular work and wall stress. They have been shown to reduce experimental infarct size and to increase anginal threshold in humans. 4. After experimental or human myocardial infarction that results in significant left ventricular dysfunction, ACE inhibitors prevent ventricular dilatation and development of congestive heart failure, and may improve survival. 5. ACE inhibitors can prevent ventricular fibrillation and contractile impairment (stunned myocardium) associated with reperfusion injury after experimental myocardial ischaemia. 6. ACE inhibitors reduce preload and afterload, improve exercise capacity, reduce ventricular arrhythmias, and improve patient survival in clinical cardiac failure. 7. Taken together, inhibition of the RAS may potentially result in primary as well as secondary protective effects on the cardiovascular system.
 ...
PMID:Clinical implications for therapy: possible cardioprotective effects of ACE inhibition. 269 Sep 9

The biochemical abnormalities associated with heart failure include dysfunction of contractile proteins, functional impairment of energy-linked enzymes and disruption of cell membrane structure. The haemodynamic impairment resulting from cardiac dysfunction activates several neurohormonal systems, notably the renin-angiotensin-aldosterone system, sympatho-adrenal system and vasopressin release, whilst clinically important factors include an enlarged heart, increased systolic wall stress and an increased myocardial oxygen demand. An inverse relationship exists between systolic wall stress (afterload) and contractile function in heart failure. Moreover the increased systolic wall stress that occurs as a result of reduced cardiac output raises myocardial oxygen consumption, causing cardiac function to deteriorate still further. Diastolic abnormalities play an important role in hypertrophic disorders, in ventricular dilatation and in cases of myocardial ischaemia. The therapeutic objectives are therefore to decrease heart size, to reduce wall stress and oxygen demand, and to enhance diastolic distensibility.
 ...
PMID:Contractile, haemodynamic and neurohormonal abnormalities in heart failure. 280 88

Angiotensin converting enzyme (ACE) inhibitors are not known to have a direct effect on the myocardium. However, there is some evidence to suggest that they can play an important role in protecting the heart during the evolution of hypertensive and coronary arterial disease, both acutely and on a long term basis. Reduction of afterload by balanced arterial and venular dilatation has led to a sustained improvement of cardiac performance both in hypertension and heart failure. Reversal of cardiac hypertrophy has been shown to restore inotropic responsiveness to stimulators of the adenylate cyclase system. Following myocardial infarction, captopril has prevented undue ventricular dilatation and normalized left ventricular chamber stiffness; this prevented deterioration of cardiac function and improved long term survival after infarction. Control of secondary aldosteronism and prevention of hypokalaemia can play an important role in the prevention of cardiac arrhythmias. The lack of reflex sympathetic stimulation during long term captopril therapy can also play a favourable role in that respect. Although highly speculative, evidence is accumulating that ACE inhibition could have a cardioprotective effect in acute myocardial ischaemia. It is based on the demonstration that renin can be produced by myocardial cells, that angiotensin is liberated by the ischemic myocardium and that angiotensin in high renin conditions plays an active constrictor role in regulating the coronary circulation.
 ...
PMID:Prospectives for angiotensin converting enzyme inhibition in heart diseases. 300 6

Acute myocardial infarction is associated with complex neuroendocrine changes, including release of arginine vasopressin, norepinephrine, and epinephrine, and activation of the renin-angiotensin system. Arginine vasopressin levels are maximal on admission, and subsequently fall even in patients in whom left ventricular failure develops. Plasma levels of norepinephrine and epinephrine are at their highest on admission and return to the normal range in patients with uncomplicated infarction, but they remain significantly elevated in patients in whom left ventricular failure or late ventricular arrhythmias develop. In contrast to catecholamines and arginine vasopressin, plasma renin and angiotensin levels are within normal limits on admission in patients without complications but increase by the third day. Patients with left ventricular failure already have increased plasma levels of renin and angiotensin on admission, but further marked and persistent increases occur over the following days. All of the aforementioned hormones may interact to cause systemic or coronary vasoconstriction, which may have short-term adverse hemodynamic consequences. Furthermore, increased afterload may result in infarct expansion and left ventricular dilatation, which will impair left ventricular function still further. Interruption of the cycle of vasoconstriction and worsening left ventricular failure by angiotensin converting enzyme inhibitors may reduce the incidence of heart failure after myocardial infarction.
 ...
PMID:Neuroendocrine changes in acute myocardial infarction. 306

The principle functions of the heart are to accept blood from the systemic and the pulmonary circulatory system, pump and deliver it to the whole body tissues and lungs. The term "heart failure" is used to describe the pathophysiological state in which an abnormality of cardiac function is responsible for failure of the heart to pump blood at a rate commensurate with the requirements of the metabolizing tissues, or to do so only from an elevated filling pressure. Thus, for a long period, heart failure has been thought of as a mechanical disorder of the heart and vessels, and its treatment has been based on improving impaired cardiac function and hemodynamic disorder. Recently multi-center, randomized placebo-controlled survival trials revealed that pure inotropic agents such as phosphodiesterase inhibitors succeeded in mechanical improvement, yet not only failed to prolong the patient's life, but also increased mortality. A number of neurohumoral mechanisms, which are activated in heart failure, were thought to be compensatory ones. However, survival trials demonstrated that two types of drug interfering with the renin-angiotensin system and the sympathetic nervous system reduced mortality. Those drugs are angiotensin-converting enzyme (ACE) inhibitors and beta blockers. ACE inhibitors reduce the direct effects of angiotensin II on myocardial cells, which may lead to cell necrosis, imbalanced remodeling through fibrosis, and attenuate the progressive ventricular dilatation. Local tissue renin-angiotensin system may be potentially important in regulating the angiotensin II production in both heart and vessels.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:[Pathophysiology and treatment of congestive heart failure--recently advanced strategy for heart failure]. 774 73

ACE inhibitors improve not only symptoms and signs of heart failure in patients with symptomatic left ventricular dysfunction but also lead to a slower progression of heart failure. In asymptomatic patients with left ventricular dysfunction, the progression to symptomatic heart failure is retarded by ACE inhibitors. As heart failure is preceded in about 80% by myocardial infarctions, trials were designed to influence the development of heart failure after myocardial infarction. It could be shown that therapy with ACE inhibitors ameliorates the progressive left ventricular dilatation and that this effect is translated into a significant increase of life expectancy. Mainly based on the CONSENSUS I study, large doses of ACE inhibitors were used in most subsequent trials. The mean daily doses of enalapril were 18.4 mg in the CONSENSUS I trial and 16.6 and 16.7 mg in both arms of the SOLVD trial. There is a trend towards lower doses of ACE inhibitors, as in the SAVE trial only 79% of the patients taking captopril received the target dose of 150 mg daily. Smaller studies used similar target doses, but a beneficial effect on left ventricular enlargement has been shown with a daily dose of only 75 mg captopril. Based on the hypothesis that the left ventricular enlargement is mainly determined by the activation of the local cardiac renin angiotensin system, even lower, and therefore better tolerated, doses of ACE inhibitors may prove effective. However, studies comparing the effect of different doses of ACE inhibitors on left ventricular remodeling are missing. Consequently, the above-mentioned target doses of ACE inhibitors should be aimed at when treating patients after myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Dosing of ACE inhibitors in postinfarct protection. 801 63

To investigate the contribution of the cardiac renin-angiotensin system to ventricular dilatation after myocardial infarction, we examined the effects of 3-week treatments with an angiotensin converting enzyme inhibitor, delapril, and a selective angiotensin II type 1 (AT1) receptor antagonist, TCV-116, on haemodynamics and ventricular angiotensin II contents in myocardial-infarcted rats. TCV-116 reduced mean aortic pressure, and prevented the increase of right and left ventricular weight, left ventricular end-diastolic pressure and volume of myocardial-infarcted rats, to a similar extent to delapril. Thus, AT1 receptor-mediated action of angiotensin II plays a central role in the development of ventricular dilatation. Angiotensin II contents in the right and non-infarcted left ventricles (6.0 +/- 1.0 and 5.9 +/- 0.7 pg/g tissue, respectively, mean +/- S.E.M.) of myocardial-infarcted rats were not different from those of sham-operated rats. However, angiotensin II contents in the infarcted scar (21.7 +/- 3.5 pg/g) of myocardial-infarcted rats were 4.2-fold higher than those in the left ventricle of sham-operated rats. Delapril reduced angiotensin II contents in the right and non-infarcted left ventricles, and the scar by 48, 81 and 60%, respectively, but did not reduce plasma angiotensin II in myocardial-infarcted rats. TCV-116 also decreased angiotensin II in the right and non-infarcted left ventricles by 57 and 56%, respectively, while increased plasma angiotensin II by 4.3-fold. Thus, the prevention of ventricular dilatation by these two agents was associated with the decrease in ventricular angiotensin II contents. These observations suggest that the cardiac renin-angiotensin system rather than the circulating system may play an important role in ventricular dilatation after myocardial infarction.
 ...
PMID:Contribution of cardiac renin-angiotensin system to ventricular remodelling in myocardial-infarcted rats. 830 70


1 2 3 Next >>