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Query: UMLS:C0026850 (muscular dystrophy)
 5,870 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 17-year-old boy with Duchenne's muscular dystrophy and congestive cardiomyopathy with a left ventricular thrombus is described. The patient presented with flank pain, and computed tomography of the abdomen revealed multiple bilateral renal infarcts. An echocardiogram delineated a left ventricular thrombus and generalized hypokinesis with a left ventricular ejection fraction of 25%. Heparin therapy was started, but the patient died of refractory congestive heart failure. Autopsy revealed diffuse skeletal myopathy consistent with Duchenne's muscular dystrophy as well as biventricular cardiomyopathy with a recent left ventricular apical-septal mural thrombus. Right atrial thrombus, a left upper lobe pulmonary embolus, and splenic and renal infarcts were also noted. To our knowledge, this is the first reported case of left ventricular thrombus with or without systemic emboli in the cardiomyopathy of Duchenne's muscular dystrophy.
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PMID:Left ventricular thrombus and systemic emboli complicating the cardiomyopathy of Duchenne's muscular dystrophy. 281 62

The number of putative calcium channels in cardiac muscle from young adult hamsters (60 days old) was compared in normal (F1B) hamsters and two different mutant strains (CHF 146 and Bio 14.6) which express cardiomyopathy and muscular dystrophy. Equilibrium binding assays of high affinity sites for [3H]-nitrendipine in ventricular homogenate preparations showed that the maximum number of [3H]-nitrendipine binding sites (Bmax), which corresponds to the number of putative calcium channels, was not significantly different in normal and cardiomyopathic hearts: 79(SEM 9), 64(14) and 69(10) fmol.mg-1 protein in 4-6 hearts from F1B, Bio 14.6 and CHF 146 hamster strains, respectively. Similar results were obtained with binding data after partial purification of the preparation. These data are in agreement with earlier studies comparing two normal strains (CHF 148 and random bred Syrian hamsters) with cardiomyopathic (CHF 146) hamsters, and conflict with other studies comparing normal and cardiomyopathic hamsters. Comparisons with the conflicting data suggest (a) that change in the number of high affinity [3H]-nitrendipine binding sites is not responsible for calcium overload and cell necrosis in cardiomyopathy, and (b) that increased numbers of low affinity [3H]-nitrendipine binding sites may emerge in cardiomyopathic hearts.
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PMID:[3H]-nitrendipine binding sites in normal and cardiomyopathic hamsters: absence of a selective increase in putative calcium channels in cardiomyopathic hearts. 285 22

The myopathic Syrian hamster is a genetic model of congestive heart failure that exhibits focal myocytolytic necrosis in both heart and skeletal muscle. Previous investigations of microvascular morphology in heart and skeletal muscle have shown severe arteriolar constrictions without fixed anatomical vessel lesions. This study tested the hypothesis that these constrictions indicate a hyperreactivity of the myopathic microvasculature in vivo and that the reactivity corresponds to the developmental course of myocyte pathology. The microcirculation of the cremaster muscle was studied in eight myopathic and six control hamsters in the active stage of necrosis (39-81 days of age) and five myopathic and six control hamsters in the later stage of muscle healing (150-213 days of age). The internal diameter of second order arterioles was measured during topically applied noradrenaline. The myopathic arterioles of the younger group constricted at significantly lower concentrations of noradrenaline (p less than 0.01) and constricted to 35-50% of their resting internal diameter over a narrower range of noradrenaline (p less than 0.01). This indicated both a reduced threshold to noradrenaline and an enhanced response to the agonist. Active myocytolytic necrosis was found in the contralateral cremaster muscle of each myopathic hamster. The older myopathic and control hamsters showed no significant differences in arteriolar responsiveness to applied noradrenaline and no active necrosis. These results indicate a relation between a hyperreactive microvasculature and active necrosis and a normal reacting microvasculature and diminished necrosis in the two phases of the disease. Thus a general correspondence between vascular responsiveness and myocyte pathology exists in this model of heart failure and muscular dystrophy.
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PMID:Microvascular reactivity of the myopathic Syrian hamster cremaster muscle. 337 Jun 64

Autopsy studies have shown that cardiomyopathy of Duchenne's muscular dystrophy (DMD) is characterized by fibrosis of the posterobasal and contiguous lateral wall of the left ventricle. This study was designed to determine whether stress testing would improve the sensitivity of echocardiography to detect secondary impairment of regional myocardial function. 12 patients aged 5 to 23 years with DMD were investigated. TM- and 2D-echocardiograms were performed before and during graded infusion of angiotensin (A) (0.5 to 5.0 mcg/min), and parameters of cardiac function analyzed. Satisfactory echocardiograms were obtained in all patients. Stress testing with A proved feasible in DMD and did not interfere with echocardiography. Before A all patients were in regular sinus rhythm and free of cardiac symptoms. Left ventricular function was normal in 9 patients and considered abnormal in 3 patients with hypokinesis and increased echo intensity of the posterobasal and lateral wall (2D short axis view) and/or a posterior wall to septal amplitude ratio of less than or equal to 1.1 (TM-echocardiogram). During A mean blood pressure rose and heart rate dropped significantly. 9 patients had marked supraventricular arrhythmias, 8 complained of dyspnea, cough or chest pain. Hypo- or akinesis of the posterobasal and sometimes the lateral wall was seen in 8, and a posterior wall to septal amplitude ratio of less than or equal to 1.1 in 9 patients. 3 patients, all with a muscle score of 60% or higher, remained free of symptoms and had no regional contraction abnormalities. Thus, clinical symptoms during A suggested latent congestive heart failure in many of the patients, and echocardiography identified provokable contraction abnormalities of such segments of the ventricular wall known to be most frequently involved in the dystrophic process in DMD. Stress testing revealed a correlation between clinical symptoms, abnormal echocardiographic findings and extent of the skeletal muscle disease in our study group. Physical limitation seems to protect the heart against demands that would otherwise cause earlier clinical manifestation of the cardiomyopathy in DMD.
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PMID:[Cardiac manifestation of progressive muscular dystrophy of the Duchenne type]. 378 61

Cardiac illness in myotonic muscular dystrophy (MyD) is infrequent, but subclinical cardiac involvement in MyD is very common (found in 42 of 46 subjects) and may be responsible for sudden death. In this series, we found ECG abnormalities in 72%, left ventricular dysfunction in 70%, mitral valve prolapse in 37%, and sudden death in 4%. Four deaths during the study period were due to acute left ventricular failure, one to sepsis and respiratory insufficiency, and one was unexplained. We did not find ominous bradyarrhythmias or atrioventricular block, evidence of congestive heart failure, noninvasive evidence of coronary artery disease, or any correlation of type or amount of cardiac involvement with any clinical parameter such as age, sex, or severity of systemic dystrophy. We feel tachyarrhythmias may play as important a role in sudden death of myotonic muscular dystrophy subjects as bradyarrhythmias, and coronary artery disease in addition to cardiac dystrophy may produce arrhythmias and myocardial dysfunction in myotonic muscular dystrophy. In addition, some subjects have an unusual form of resting left ventricular dysfunction which improves with exercise. The most important problem in the clinical management of myotonic muscular dystrophy subjects is sudden death, and the solution does not appear to be empiric ventricular pacing. Our recommendations for prophylaxis of sudden death in myotonic muscular dystrophy are noninvasive investigation of coronary artery disease in subjects with significant risk factors, with angiography and surgery if indicated: detailed evaluation of syncopal and presyncopal events, including electrophysiologic testing, with pacemaker or antiarrhythmic drug therapy if indicated; and consideration of ventricular pacing of asymptomatic subjects if severe bradycardia or marked intraventricular conduction delay develops during follow-up, serial 12-lead ECGs. The documentation of tachyarrhythmias during sudden death and syncopal episodes in myotonic muscular dystrophy subjects makes ventricular pacing alone an uncertain modality for prevention of sudden death in subjects with only mildly lengthened PR or QRS intervals, and suggests a combination of pacemaker and antiarrhythmic drug therapy for the myotonic muscular dystrophy subject with syncope of no apparent cause.
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PMID:Cardiac involvement in myotonic muscular dystrophy. 405 3

Myocardial involvement in progressive muscular dystrophy of the Duchenne type was evaluated in 19 patients using thallium-201 myocardial perfusion imaging. A qualitative analysis was performed from five projection images by three experienced physicians. Distinct perfusion defects were shown in 13 patients, especially in the LV posterolateral or posterior wall (11 patients). There was no significant relationship between the presence of perfusion defects and the skeletal muscle involvements or thoracic deformities assessed by transmission computed tomography. Extensive perfusion defects were shown in 2 patients who died of congestive heart failure 1 to 2 years after the scintigraphic study. Progression of the myocardial scintigraphic abnormalities were considered to be minimal in 7 of 9 patients who underwent two serial scintigraphic studies over 2 to 3 years. It was concluded that thallium myocardial perfusion imaging is a useful clinical technique to assess myocardial involvement in Duchenne's progressive muscular dystrophy.
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PMID:Evaluation of myocardial involvement in Duchenne's progressive muscular dystrophy with thallium-201 myocardial perfusion imaging. 408 70

It is not surprising that calcium-channel blocking agents, which have numerous effects on various physiologic systems, have been employed for several "unapproved" uses. This manuscript reviews reports that have appeared within the last two years describing unapproved cardiovascular and noncardiovascular uses of the three available calcium-channel blocking agents. The cardiovascular uses discussed include hypertensive emergencies, pulmonary hypertension, congestive heart failure, aortic insufficiency, Raynaud's phenomenon, migraine headaches, antiplatelet effects and cardiac surgery. Areas of noncardiovascular use include muscular dystrophy, achalasia, esophageal spasm, dysmenorrhea, preterm labor, asthma, hyperuricemia, mania and depression and endocrinologic and oncologic conditions. While some of the data appear promising, other reports are conflicting and contradictory. Furthermore, because much of the information comes from poorly controlled trials or anecdotal reports, even the more promising uses must be studied further and compared with conventional therapy.
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PMID:Promising uses of calcium-channel blocking agents. 637 47

The physiatrist can now be instrumental in prolonging the survival of individuals with neuromuscular disease by using respiratory muscle aids. As a result, morbidity and mortality from cardiomyopathy are likely to increase for patients with generalized myopathies. One hundred consecutive patients with dystrophin-deficient muscular dystrophy and a mean age of 17.2 yr (range, 5-41) satisfied criteria for having dilated cardiomyopathy (DCM) and received digitalis and diuretics. Nine of the 14 patients were symptom-free, despite left ventricular ejection fractions (LVEFs) of 25-40%. The five patients with symptomatic heart failure had severe ventricular dilatation, with LVEFs < 25%. Two of the five patients died of heart failure within 1 yr. For the remaining three patients, we evaluated the addition of the angiotensin-converting enzyme (ACE) inhibitor enalapril and, subsequently, the use of beta-blockers to the therapeutic regimen. Addition of these medications, never before attempted in the management of cardiomyopathy associated with generalized myopathic disease, complemented each other in relieving symptoms and reversing signs of congestive heart failure and DCM. We conclude that the combination of ACE inhibitor and beta-blocker deserves further exploration for inclusion in any management regimen for the treatment of muscular dystrophy-associated cardiomyopathy.
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PMID:A management trial for Duchenne cardiomyopathy. 757 10

Membrane-mediated excessive intracellular calcium accumulation (EICA), and diminished cellular energy charge are invariably present in the myocardium of CHF-146 strain dystrophic hamsters (DH) with hereditary muscular dystrophy (HMD) and hypertrophic cardiomyopathy (HC). Therefore, we investigated respiratory dysfunctions and Ca2+ overloading in the isolated cardiac mitochondria from young and old DH, and whether these abnormalities can be reversed by controlling EICA in the in vitro mitochondria upon chelating excessive Ca2+ from the isolation medium with EDTA. Age- and sex-matched CHF-148 strain albino normal hamsters (NH) served as the disease controls. As an index of membrane-mediated EICA and chronic cellular degeneration, Ca and Mg concentrations were quantitated in the ventricular myocardium and in the cardiac mitochondria harvested in two different isolation media. Mitochondria from young and old DH, isolated in the absence of 10 mM EDTA (B0 medium), revealed poor coupling of oxidative phosphorylation, diminished stimulated oxygen consumption rate, and lower respiratory control and ADP/O ratios, than those seen in NH. However, incorporation of 10 mM EDTA in the isolation medium (B medium) restored the mitochondrial functions and reduced massive Ca(2+)-overloading in the dystrophic organelles. Ca concentration in the in vitro mitochondria from DH was significantly higher than in NH, irrespective of the composition of the isolation medium and age of the hamsters. Furthermore, the dystrophic organelles isolated in B medium had a much lower Ca concentration, and markedly improved oxidative phosphorylation as seen in the cardiac mitochondria from NH, compared to those prepared using B0 medium.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reversal of impaired oxidative phosphorylation and calcium overloading in the in vitro cardiac mitochondria of CHF-146 dystrophic hamsters with hereditary muscular dystrophy. 813 8

Idiopathic dilated cardiomyopathy (DCM) is characterised by ventricular dilatation and impaired systolic function resulting in congestive heart failure and frequently death. A dilated cardiomyopathy is common in patients with symptomatic Duchenne/Becker muscular dystrophy, a disease caused by dystrophin gene defects. However, cardiomyopathy is rarely the predominant clinical feature of this form of muscular dystrophy. To determine whether dystrophin gene defects might account for a significant number of patients with apparently isolated idiopathic DCM, we performed dystrophin gene analysis in 27 DCM patients, who were ascertained as part of a prospective study on idiopathic DCM. No dystrophin gene defects were found in our patients, whose average age was 50 years. These data suggest that dystrophin defects are not a common cause of idiopathic DCM in this age group in the absence of skeletal muscle cramps or weakness.
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PMID:Dystrophin analysis in idiopathic dilated cardiomyopathy. 830 53


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