Search

2022 DEC 17 (NewsRx) -- By a News Reporter-Staff News Editor at Obesity, Fitness & Wellness Week -- Researchers detail new data in cardiomyopathies. According to news reporting originating from [...]

Case presentation One week postpartum, one of your patients calls to report that her leg swelling has gotten significantly worse over the past several days. Mrs. Smith is a 32-year-old [...]

Heat shock protein (Hsp)60 and IGF-1 receptor signaling protect cardiac muscle against injury. The abundance of cardiac IGF-1 receptor can be upregulated by Hsp60, but how diabetes modulates cardiac muscle Hsp60 has not yet been defined. We investigated the changes of Hsp60 and IGF-1 receptor signaling in the diabetic myocardium and studied how diabetes modulates Hsp60 and IGF-1 receptor in diabetic myocardium. In the streptozotocin (STZ)-induced diabetic rat, down-regulation of Hsp60 and IGF-1 receptor occurred 4 days after induction of diabetes. IGF-1 activation of IGF-1 receptor, Mek, and Akt were reduced accordingly in the diabetic myocardium. The independent effect of insulin and hyperglycemia on Hsp60 was investigated in primary cardiomyocytes. Incubating cardiomyocytes with insulin was associated with dose-dependent increase of Hsp60 protein. In contrast, the abundance of Hsp60 was not affected by high concentration of glucose in these cells. To further determine the independent effects of hyperglycemia and insulin deficiency on the changes of myocardial Hsp60 and IGF-1 receptor, we used phlorizin to normalize blood glucose in diabetic rats. In the phlorizin-treated diabetic rats, myocardial Hsp60 was lower than that of the normal controls. In contrast, insulin treatment normalized myocardial Hsp60 in the diabetic rats. Because phlorizin does not alter insulin secretion, Hsp60 expression was modulated by insulin and not by hyperglycemia. Similar changes of Hsp60 and IGF-1 receptor were observed in the skeletal muscle of STZ-induced diabetic rats. These findings suggest that insulin deficiency is a novel mechanism that leads to downregulation of Hsp60 in diabetic muscle tissues. The development of diabetic cardiomyopathy might have involved downregulation of Hsp60 and subsequent reduction of IGF-1 receptor signaling., Abnormalities of cardiovascular systems are common in diabetic patients, and the consequences of cardiac disease in diabetes are devastating (1). In addition to coronary artery disease and hypertension, diabetic patients [...]

Women who have experienced peripartum cardiomyopathy and whose left ventricular size and performance have recovered may still have a reduced contractile reserve. Peripartum cardiomyopathy is a rare complication of pregnancy involving heart failure in the first half or last month of pregnancy. Researchers measured contractile reserve with a dobutamine challenge test on seven women who had recovered from peripartum cardiomyopathy. Recovered women had normal starting heart rates, blood pressures, ventricular size and left ventricular function. After dobutamine challenge, however, contractile reserve was decreased.

The relationship between maximal exercise tolerance and resting radionuclide indexes of left ventricular systolic and diastolic function were evaluated in 20 ischemic and 44 idiopathic cardiomyopathy patients with New York [...]

Dilated cardiomyopathy is a disease of the heart muscle involving an enlarged left ventricle (the heart chamber which pumps oxygenated blood to the body), with consequent loss of efficiency in pumping action. The pressure in the jugular vein, which returns blood from the brain to the heart, reflects the volume and pressure of the venous blood in the right side of the heart. It is often high in these patients, which is usually taken to mean congestive heart failure, a failure of the heart to keep up with the demands of the body. However, this may not always be the case. A dominant 'a' wave showing up on an electrocardiogram more likely identifies a problem with right ventricular filling with blood returning from the jugular vein. Twenty-three patients with dilated cardiomyopathy were examined. Eleven had a dominant 'a' wave and 12 had a dominant 'v' wave. Patients with the dominant 'a' wave had a higher heart rate and a different filling time. Possible mechanisms for the 'a' wave pattern are discussed. The most likely explanation is that the pattern reflects the direct effect of the limited time available for blood to flow in. When this condition is misdiagnosed as congestive heart failure, it is usually treated with diuretics to reduce blood volume. This would be ineffective if the problem is one of filling time, which responds to lowering the heart rate or reducing the duration of tricuspid regurgitation (backflow of the blood through a defective valve), both of which would increase the filling time. Heart failure is an imprecise diagnosis, and this noninvasive method of refining the diagnosis leads to more effective treatment. (Consumer Summary produced by Reliance Medical Information, Inc.)

A case is described of a 38-year-old man who developed cardiomyopathy (disease of the heart muscle) and pulmonary infiltrates (accumulation of fluid within the lung). The patient had a heart attack in March 1988 and was shown to have narrowing of the left main coronary artery. The function of the left ventricle was depressed and the heart was enlarged. Coronary bypass surgery was performed, which is an operation to restore blood flow to the heart, and the patient was placed on therapy with steroids to prevent inflammation of the aorta and pericardium (a membrane that surrounds the heart). A biopsy of heart tissue taken during surgery revealed fibrosis, the formation of fiber-like tissue. In September 1988, the man developed heart failure and did not improve despite treatment with antibiotics for possible infection of the lungs. He had an enlarged heart and persistent infiltrates in the right mid-lung area. The patient was diagnosed with fibrosing mediastinitis, the inflammation of the mediastinum (the mass of tissue including the heart and associated blood vessels that separate the lungs). The mediastinitis was associated with fibrosis, and resulted in heart attack, cardiomyopathy, congestive heart failure, and pulmonary infiltration. The pathologic findings and X-ray studies are reviewed. (Consumer Summary produced by Reliance Medical Information, Inc.)

An evaluation and a comparison of left ventricular regional wall motion were performed in 32 patients with idiopathic dilated cardiomyopathy, none of whom had coronary artery diameter stenosis exceeding 20% in any major artery, and 17 control subjeck, using frame by frame video intensity analysis of digitized ventriculograms. This technique evaluates the whole cardiac cycle in short overlapping intervals and yields information for systolic and diastolic events, without assumptions regarding the position and orientation of the ventricle. Diastolic regional wall motion abnormalities were found in 31 of 32 patients and systolic abnormalities were present in 16 patients. Asynchronous regions most commonly detected during diastole were anteroapical and apical; they were found in 19 of 32 patients. Regional contraction abnormality was observed in the apical and the anteroapical regions in 6 of 16 patients. Dilatation-induced changes in left ventricular shape exaggerate the phenomenon of higher wall stress at the apex of the normal ventricle. Basal wall motion is thus relatively preserved in dilated cardiomyopathy. (Am J Cardiol 1990;6S:364-370), Cardiomyopathy, or an abnormality of the heart muscle, generally makes its presence known by affecting the output of the heart (the volume of blood pumped by the heart). However, within the heart, all ventricular muscle may not be the same. Since the output of the heart only provides insight into global function, more sophisticated techniques are necessary to examine the function of individual areas of heart muscle. One such technique is the application of digital image analysis to angiography. A study of 32 patients with idiopathic dilated cardiomyopathy and 17 controls with apparently normal heart function was conducted using motion picture and video angiography. Rather than merely viewing the pictures of the beating heart, the individual image frames were digitized and analyzed by computer. Using this method it was possible to detect asynchronous relaxation of the wall of the ventricle in the cardiomyopathy patients. Thirty-one of 32 patients showed some asynchronous relaxation; 40 percent also showed some abnormalities in contraction as well. Many previous studies analyzed only abnormalities in the contraction of the ventricles, and thus have underestimated the actual frequency of abnormalities of heart wall motion. Most of the abnormalities of the heart wall in this study were observed in the region of the apex, or pointed end, of the heart. This is most likely due to the fact that as the ventricle dilates, the apex loses some of the small radius of curvature which normally serves to protect it from pressure. Furthermore, the wall of the heart is thinnest at the apex, and as the heart dilates, this thin muscle becomes thinner and is subject to increasing stress with delayed contraction and relaxation. (Consumer Summary produced by Reliance Medical Information, Inc.)

Background: Cardiomyoplasty utilizes the latissimus dorsi muscle to boost the failing ventricle. However, the mechanism for clinical improvement still remains controversial. We have previously shown that left ventricular contraction was [...]

Ming Yan, MD,PhD(*); Phillip I Bird, PhD; John P Dowling, MD and Yean Leng Lim, MD,PhD. Cardiac Research Laboratory, National Heart Centre, Singapore; Department of Medicine, Box Hill Hospital, VIC, [...]

Our studies have shown that normal adult rat ventricular myocytes cultured for 1-2 days in high extracellular glucose exhibit prolonged action potentials, slower cytosolic [Ca.sup.2+] clearing and prolonged relaxation. These [...]

Background: There has been no report of ECG changes during anginal attacks in patients with coexistent hypertrophic cardiomyopathy (HCM) and vasospastic angina. Study objectives: To elucidate the change in ST-segment [...]

Doppler echocardiographic indexes of ventricular inflow have been used clinically to characterize left ventricular (LV) diastolic function. The reliability of these indexes as markers for intrinsic myocardial diastolic properties has been questioned. Micromanometer left atrial (LA) and LV pressures as well as transmitral Doppler flow velocity signals and M-mode and 2-dimensional echocardiograms were simultaneously recorded. These unique measurements were acquired in patients with dilated cardiomyopathy under baseline conditions and during infusion of high dose amrinone. The response to amrinone was chosen as a hemodynamic model because this drug has previously been described as having beneficial effects on overall LV systolic and diastolic performance. At peak amrinone effect, LV contractility increased (as assessed using load independent end-systolic indexes) and early diastolic relaxation improved whereas passive chamber stiffness, heart rate and stroke volume were unchanged. There was a significant decrease in LV end-diastolic pressure as well as a parallel downward shift of the entire LV diastolic pressure-dimension relation. These findings, which indicated an improvement in overall LV diastolic properties, probably represent the combination of more rapid early diastolic relaxation in conjunction with a reduction in venous return, the relief of pericardial restraint or the reduction in right ventricular-LV interaction. in contrast, the ratios of Doppler-determined peak transmitral early-to-late flow velocities and early-to-late diastolic flow velocity integrals decreased with amrinone infusion, thereby suggesting a drug-induced decrease in LV diastolic compliance. Thus, in patients with idiopathic dilated cardiomyopathy, administration of amrinone has a complex effect on LV diastolic properties. in these patients the most commonly used Doppler criteria for LV filling properties have to be used cautiously because the derived conclusions may be diametrically opposed to the actual hemodynamic changes. (Am J Cardiol 1989;64:1173-1179), Doppler echocardiography, in which sound waves are used to visualize internal heart structures, has been utilized to assess the function of the left ventricle of the heart during diastole, the relaxation phase of the heart cycle. The reliability of measurements of blood flow into the ventricle for reflecting the diastolic function of the heart has not been established. Hence, measurements of ventricular inflow by Doppler echocardiography were compared with direct measurements of pressures within the left atrium and ventricle in patients with dilated cardiomyopathy, or heart disease associated with dilation of the heart. Measurements were made before and after treatment with the cardiovascular agent amrinone, which was shown to improve the function of the left ventricle. Amrinone increased contractility and relaxation of the ventricle, and decreased pressures in the left ventricle at the end of diastole. It had no effect on the chamber stiffness (rigidity of the ventricular wall), heart rate, or stroke volume, which is the amount of blood pumped by the left ventricle with each heartbeat. Improvement in left ventricular function during diastole may result from: early relaxation of the ventricular muscle during diastole; decreased venous return, or amount of blood returning to the heart; less restriction by the pericardium which surrounds the heart; and reduced interaction between the right and left ventricles. However, results from Doppler echocardiography studies showed that amrinone decreased left ventricular inflow, suggesting a drug-induced decrease in compliance, or flexibility, of the left ventricle during diastole. These findings show that amrinone has complex effects on left ventricular properties during diastole in patients with dilated cardiomyopathy of unknown cause. In addition, the results obtained by Doppler echocardiography must be interpreted with caution, because of the chance that the conclusions indicated by this technique could be directly opposite to what is actually happening in the heart. (Consumer Summary produced by Reliance Medical Information, Inc.)

Many heart problems have been found in patients with infected with human immunodeficiency virus (HIV)(virus responsible for AIDS). These include fluid accumulation, high pressure in the pulmonary artery, infections of the heart lining, and tumors. Dysfunction of the left ventricle, the major pumping chamber of the heart, has become the most frequently reported cardiac complication associated with HIV infection. Autopsies have uncovered asymptomatic cardiomyopathy (disease of the heart muscle) or myocarditis (heart muscle inflammation) in up to half of patients with AIDS. Echocardiograms (ultrasound records of cardiac function) have indicated heart dysfunction in up to 75 percent of AIDS patients, and this problem occurs in all groups at risk for AIDS. Due to successful treatment of opportunistic infections (namely, those affecting patients with compromised immune systems), which are the major cause of death in AIDS, and the availability of treatment for the HIV infection itself, patients are living longer and thus the occurrence of complications such as cardiomyopathy and brain dysfunction is likely to increase. This plus the increasing prevalence of HIV infection means that the incidence of HIV-related cardiomyopathy will multiply. Although echocardiography provides diagnostic information about heart dysfunction, symptoms such as breathlessness and fatigue are likely to be attributed to pulmonary disease or anemia. HIV-related myocarditis may be caused by opportunistic infections such as toxoplasmosis, which may predispose individuals to the development of heart damage. Cell damage caused by the activated immune system or by the HIV infection itself may also be a factor, as may medications used to treat HIV or opportunistic infections. Just as with the more common dilated cardiomyopathy, in which the heart muscle increases in size to compensate for reduced function, the disease processes underlying disease of the heart muscle are not well understood. Although HIV cardiomyopathy will increasingly provide cardiologists with challenges, study of patients with HIV before heart changes occur will afford an opportunity to better understand the development and progression of cardiomyopathy. (Consumer Summary produced by Reliance Medical Information, Inc.)