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)

The isolated perfused working rat heart preparation has been used to study the effects of respiratory acidosis on myocardial metabolism and contractilly. Hearts were perfused with 5 mM glucose and 10(-2) U/ml of insulin in order to enhance metabolsim of glucose relative to that of fatty acids. After perfusion with Krebs bicarbonate medium at pH 6.6, hearts rapidly ceased performing external work and peak left ventricular pressure fell by 75% after 5 minutes. Oxygen consumption, rate of ATP generation and overall glycolytic flux also declined rapidly. After about 2 minutes of perfusion, the fall of glycolytic flux showed a partial reversal, which was largely accounted for by increased lactate production, so that glucose oxidation decreased further. The reversal of glycoltic flux could be accounted for by partial release of H+ inhibition of phospho-fructokinase by increased tissue levels of adenosine 5'-diphosphate (ADP), adenosine monophosphate (AMP) and P1 and decreased levels of adenosine triphosphate (ATP) and creatine phosphate. The increased proportion of glucose uptake converted to lactate together with an increase of the tissue lactate/pyruvate ratio could be accounted for by inhibition of the malate-aspartate cycle combined with tissue hypoxia. Lactate accumulated in the tissue as a result of a decreased permeability of the plasma membrane to lactate. Decreased oxygen delivery to the myocardium was caused by secondary constriction of the coronary vessels. In further experiments, the coronary flow was regulated by an external pump which delivered fluid at a controlled rate into the aortic cannula above the coronary arteries, and the degree of tissue hypoxia was monitored by measuring changes of pyridine nucleotide reduction state by surface fluorescence techniques. The effects of acidosis uncomplicated by possible hypoxia were compared directly with those produced by ischemic hypoxia. The effects of acidosis under these conditions were similar to those described above, and to those produced by ischemia. From these and other data it is concluded that the effects of ischemia are caused by a lowering of the intracellular pH, which decreases the rate of energy production relative to the rate of energy demand. However, it is suggested that the primary cause of the decreased peak systolic pressure with either acidosis or ischemia is not a result of a defect of energy metabolism, but is due to alteration of the calcium cycle of the heart. Possible causes of irreversible heart failure after prolonged ischemia are discussed.
 ...
PMID:Contribution of tissue acidosis to ischemic injury in the perfused rat heart. 0 93

Geriatric patients are preferentially involved in ischemic bowel disease. The sudden occlusion of the large mesenteric arteries (a. mesenterica superior (more frequently) and inferior) is followed by intestinal gangrene and peritonitis with a poor prognosis and a high letality (greater than 90%). In chronic intestinal ischemia the leading clinical symptom is postprandial pain ('claudicatio intestinalis'). In some cases of acute mesenteric artery occlusion no embolus or thrombus will be found. In these cases the circulation in the arteriosclerotic vessels falls below a critical value due to cardiac insufficiency, shock, digitalis overdose and others. In less severe ischemia the mucosa is involved being most sensitive to O2 deprivation. It usually regenerates within a few days. This form is found more frequently in the colon than in other parts of the gut (about 40%): ischemic colitis. The therapy - if possible in acute, fulminant ischemia or if necessary in chronic intestinal ischemia - is surgical consisting in reconstructive procedures of the mesenteric circulation.
 ...
PMID:[Ischemic bowel disease (author's transl)]. 1 31

Digitalis and diuretics constitute conventional therapy of congestive heart failure, but systemic vasodilators offer an innovative approach in acute and chronic heart failure of decreasing increased left ventricular systolic wall tension (ventricular afterload) by reducing aortic impedance and/or by reducing cardiac venous return. Thus, vasodilators increase cardiac output (CO) by diminishing peripheral vascular resistance (PVR) and/or decrease increased left ventricular end-diastolic pressure (LVEDP) (ventricular preload) by diminishing venous tone. Concomitantly, there is reduction of myocardial oxygen demand, thereby reliably reducing angina pectoris in coronary disease, and potentially limiting infarct size and ischemia provided systemic arterial pressure remains normal. The vasodilators produce disparate modifications of cardiac function depending upon their differing alterations of preload versus impedance: nitrates principally cause venodilation (decrease LVEDP); nitroprusside, phentolamine and prazosin produce balanced arterial and venous dilation (decrease LVEDP and increase CO) provided left ventricular filling pressure is maintained at the upper limit of normal; whereas hydralazine predominantly effects arteriolar dilation (increases CO). With depressed CO plus highly increased LVEDP and increased PVR, nitrates also induce some increase of CO by reducing PVR. Combined nitroprusside and dopamine synergistically enhance CO and decrease LVEDP. Mechanical counterpulsation aids nitroprusside in acute myocardial infarction. The 30-minute venodilator action of sublingual nitroglycerin is extended for 4 to 6 hours by cutaneous nitroglycerin ointment, by sublingual and oral isosorbide dintrate, and by oral pentaerythritol tetranitrate and sustained-release nitroglycerin capsules. Ambulatory oral vasodilator therapy is provided by long-acting nitrates (relieve pulmonary congestion); hydralazine (improves fatigue); prazosin alone, combined nitrate-hydralazine combined prazosin-hydralazine (improve both dyspnea and fatigue).
 ...
PMID:Afterload reduction and cardiac performance. Physiologic basis of systemic vasodilators as a new approach in treatment of congestive heart failure. 9 30

Fibromuscular dysplasia of renal arteries was the cause of hypertension in four consecutive children with renal artery stenosis. Two were asymptomatic, the third had had hypertension for seven years but had not been treated, and the fourth, a 9-month-old infant, presented with cardiac failure. Heart enlargement and left ventricular hypertrophy were present in all. Rapid sequence urograms demonstrated a smaller kidney and delayed appearance and disappearance of the contrast medium on the affected side in all. Angiograms showed left RAS in all. Peripheral plasma renin activity was elevated in only three of the four patients. Antihypertensive and diuretic drugs were not very effective therapeutically. Ischemia of the ipsilateral kidney probably prevented normal growth and led to shrinkage of the kidney in one patient. Following nephrectomy the BP has remained normal without any therapy for 24 to 64 months. With normalization of BP, accelerated growth ensued, the cardiomegaly regressed and the hypertensive retinopathy resolved. These patients demonstrate that: (1) FMD is an important cause of RAS. (2) the well-known radiologic feature of FMD, the beaded appearance, is usually not seen in children. (3) control of BP leads to normalization of linear growth, usually impaired in severe hypertension, and (4) target organ complications such as cardiomegaly, LVH, and hypertensive retinopathy are reversible in one to 10 months.
 ...
PMID:Fibromuscular dysplasia of renal arteries: an important cause of renovascular hypertension in children. 15 54

Systemic causes of leg edema include idiopathic cyclic edema, heart failure, cirrhosis, nephrosis and other hypoproteinemic states. Lymphedema may be primary, or secondary to neoplasm, lymphangitis, retroperitoneal fibrosis and, rarely (in the U.S.), filariasis. Thrombophlebitis and chronic venous insufficiency are not uncommon causes. Finally, infection, ischemia, lipedema, vascular anomalies, tumors and trauma can be responsible for the swollen leg.
 ...
PMID:The swollen leg. 18 30

Echocardiographic findings in patients with ischemic heart disease are described; their correlations with clinical, hemodynamic and angiographic data are presented and discussed. Regional abnormalities of left ventricular wall motion and/or thickening during systole are detected in 84 per cent of patients with acute myocardial infarction and in a high percentage of patients with larger than or equal to 75 per cent narrowing of a major coronary artery. These abnormalities may occur with stress and may be reversible. Left ventricular wall thinning during systole indicates acute ischemia or infarction and thin, dense myocardial echoes indicate scar. Echocardiographic evidence of left ventricular dysfunction is useful in predicting heart failure and mortality in patients with acute myocardial infarction and in predicting surgical mortality for patients undergoing aneurysmectomy and/or coronary artery bypass surgery. Echocardiography has not proved useful in determining graft patency following coronary artery bypass surgery. Technical difficulties and limitations of echocardiography in patients with coronary artery disease are discussed.
 ...
PMID:Echocardiography in ischemic heart disease. 32 1

The relationship between energy metabolism and the extent of irreversible ischemic damage was examined in an isolated perfused working rat heart. The amount of cardiac work recovered after reperfusion of hearts exposed to severe global ischemia was dependent upon both the duration of ischemia and the type of substrate provided (either 5 mM glucose or 5 mM glucose + acetate). There appear to be two distinct phases in the ability to recover mechanical function in the reperfused ischemic heart. The second phase corresponds to the onset of severe irreversible tissue damage. Irreversible mitochondrial damage was not found to correspond with the onset of heart failure since the ATP/ADP ratio remained constant in the reperfused myocardium. Furthermore, there does not appear to be a direct correlation between the total ATP content and the extent of irreversible damage, either during ischemia or following reperfusion. However, the total adenine nucleotide content during ischemia showed dramatic changes which correspond temporally with the initiation of the second phase of damage. The observation that the adenine nucleotide pool becomes further depleted during reperfusion suggests that alterations in the salvage pathway for adenine nucleotide synthesis have occurred. Loss of adenine nucleotides appears to be an excellent marker for irreversible heart failure. Acetate provides some protection the the ischemic myocardium. The mechanism by which acetate mediates this protective effect is discussed.
 ...
PMID:Relationship between adenine nucleotide metabolism and irreversible ischemic tissue damage in isolated perfused rat heart. 44 6

Serial treadmill exercise testing (mean 5.5 tests/patient) was used to evaluate the prognosis of 200 males (mean age 53 years) without clinical heart failure or unstable angina pectoris 3 weeks after acute myocardial infarction (MI). Exercise-induced ischemic ST-segment depression greater than or equal to 0.2 mV 3 weeks after MI was significantly more prevalent in patients with subsequent cardiac arrest (100%) or coronary artery bypass graft surgery (64%) than in patients without subsequent events within 2 years of infarction (35%) (p less than 0.05). Exercise-induced ventricular arrhythmia on multiple tests 5-52 weeks after MI was more prevalent in patients with recurrent myocardial infarction (90%) than in patients without subsequent events (47%) (p less than 0.001). By contrast, exercise-induced ventricular arrhythmia on a single test at 3 weeks was a less powerful predictor of subsequent cardiac events. Exercise-induced ischemia 3 weeks after MI predicted early fatal events, while ventricular arrhythmia on serial testing predicted later nonfatal events.
 ...
PMID:The prognostic significance of serial exercise testing after myocardial infarction. 49 48

Eighteen infants carrying pulmonary stenosis with a complete interventricular wall whose most frequent clinical data are: precocius cyanosis, congestive cardiac insufficiency and in 25% of them hypoxic crises are presented. Complementary explorations of this entity are not definitive, but clinical diagnosis described with evolutional cardiomegaly at the expense of the right cavities and pulmonary ischemia forces authors to think that there is a severe obstruction of the infumdibulum with complete interventricular septum. The different parameters which have been proposed to evaluate severity of the stenosis are discussed and compared, finding among them significative differences. Authors consider the concept of the right diminutive ventricle, finding in these cases the electrocardiographic pattern rS in V1 and observing a great mortality both spontaneous and postsurgical. The high mortality of this heart disease, both in its' natural evolution as well as after surgery is to be pointed out as in most published series.
 ...
PMID:[Critical pulmonary stenosis in infants (author's transl)]. 50 75

In 21 patients with ischaemic heart disease, the values of the anginal threshold were investigated during cardiac pacing and an exercise test. It was found that in the pacing test, ischemia could be expected to appear at a heart rate by 30% faster than that in ischaemia induced by exercise. If ischaemia was successfully induced in both tests, the threshold values of the time-tension indexes were equal, whereas the value of the pressure-time per minute index was 20% higher in exercise-induced ischaemia. In patients with hypokinetic circulation, during pacing the pressure-time per minute index first increased and then paradoxically decreased; this reaction can help find out patients with haemodynamic signs of heart failure.
 ...
PMID:A comparison between cardiac pacing and exercise tests in patients with angina pectoris. 61 Sep 93


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