Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Myocardial bridging (MB) is a rare coronary anomaly in children that is typically associated with hypertrophic cardiomyopathy or left ventricular hypertrophy. Several reports, mainly in adults, have suggested an association between MB and sudden death or ischemia without other cardiac abnormalities. In this report, we describe an 11-year-old girl with syncope and manifestations of cardiac ischemia associated with MB of the middle segment of the left anterior descending artery. The coronary anomaly was not associated with left ventricular hypertrophy. Surgical unroofing of the affected coronary artery segment resulted in complete recovery. MB should be included in the differential diagnosis of children presenting with syncope and signs of ischemia even in the absence of ventricular hypertrophy.
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PMID:Symptomatic myocardial bridging in a child without hypertrophic cardiomyopathy. 1639 Sep 19

AMP-activated protein kinase (AMPK) plays a key role in modulating cellular metabolic processes. AMPK, a serine-threonine kinase, is a heterotrimeric complex of catalytic alpha-subunits and regulatory beta- and gamma-subunits with multiple isoforms. Mutations in the cardiac gamma(2)-isoform have been associated with hypertrophic cardiomyopathy and pre-excitation syndromes. However, physiological regulation of AMPK complexes containing different subunit isoforms is not well defined and is important for an understanding of the function of this signaling pathway in the intact heart. We evaluated the kinase activity associated with heart AMPK complexes containing specific alpha- and gamma-subunit isoforms of AMPK in an in vivo rat model of regional ischemia. Left coronary artery occlusion activated the immunoprecipitated alpha(1)-isoform (6-fold, P < 0.01) and alpha(2)-isoform (9-fold, P < 0.01) in the ischemic left ventricle compared with sham controls. The degree of alpha-subunit activation depended on the extent of ischemia and paralleled echocardiographic contractile dysfunction. The regulatory gamma(1)- and gamma(2)-isoforms were expressed in the heart. The gamma(1)- and gamma(2)-isoforms coimmunoprecipitated with alpha(1)- and alpha(2)-isoforms in proportion to alpha-subunit content. gamma(1)-Isoform immunocomplexes accounted for 70% of AMPK activity and AMPK phosphorylation (Thr(172)) in hearts. Ischemia similarly increased AMPK activity associated with the gamma(1)- and gamma(2)-isoform complexes threefold (P < 0.01 for each). Thus AMPK catalytic alpha(1)- and alpha(2)-isoforms are activated by regional ischemia in vivo in the heart, irrespective of the regulatory gamma(1)- or gamma(2)-isoforms to which they are complexed. Despite the pathophysiological importance of gamma(2)-isoform mutations, gamma(1)-isoform complexes account for most of the AMPK activity in the ischemic heart.
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PMID:Activation of AMPK alpha- and gamma-isoform complexes in the intact ischemic rat heart. 1664 75

Patients with apical hypertrophic cardiomyopathy (APH) associated with paradoxic jet flow (ie, diastolic flow away from the apex) may gradually develop an apical aneurysm, which often leads to arrhythmia and mural thrombus formation. We observed systolic outward motion of the left ventricular apical myocardium in patients with APH using a magnetic resonance tagging procedure and examined the relationship of the outward motion to echocardiographic and scintigraphic findings and to cardiac events. Systolic displacement of the myocardial tags of the apical region perpendicular to the long axis in the 4-chamber view was recorded in 31 patients with APH. Of these patients, 14 showed no outward movement of tags (group A), and 17 showed outward movement (group B). In group B, apical hypertrophy was more severe (35 +/- 7 mm vs. 29 +/- 6 mm, p < 0.05), paradoxic jet flow was more frequent (64% vs. 14%, p < 0.05) and the defect score in I-123-beta-methyliodophenylpentadecanoic acid scintigraphy was higher (2.1 +/- 0.7 vs. 1.3 +/- 0.7, p < 0.01). During a mean follow-up period of 55 months, only 1 patient experienced paroxysmal atrial fibrillation in group A. In group B, 1 patient died suddenly, 1 was admitted to hospital because of congestive heart failure, 2 developed angina pectoris, 2 exhibited non-sustained ventricular tachycardia, and 1 showed multifocal premature ventricular contraction; in these 7 patients the outward movement was greater than in the 10 patients in Group B who had no cardiac events (1.00 +/- 0.59 vs. 0.52 +/- 0.40, p < 0.05). Hence, our results show that outward tag displacement is frequently associated with severe apical hypertrophy, paradoxic jet flow, apical ischemia, and cardiac events. The tagging method may be useful in assessing the severity of APH and predicting the occurrence of cardiac events at an early stage.
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PMID:Systolic outward motion of the left ventricular apical wall as detected by magnetic resonance tagging in patients with apical hypertrophic cardiomyopathy. 1675 31

We present a case of symptomatic primary hypertrophic cardiomyopathy (HCM) associated with myocardial bridging of the left anterior descending (LAD) artery and suspected ischemia that could be related either to LAD artery compression or to microvascular perfusion abnormalities. MRI demonstrated the morphological appearance of myocardial hypertrophy, and coronary MR angiography evidenced the myocardial bridge and its functional consequences with stress MR perfusion. In conclusion, as a non-invasive comprehensive imaging technique, MRI should be considered in identifying the mechanisms of myocardial ischemia in HCM with myocardial bridge.
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PMID:Usefulness of MRI to demonstrate the mechanisms of myocardial ischemia in hypertrophic cardiomyopathy with myocardial bridge. 1688 85

We present the case of a 69-year-old female with a long history of apical hypertrophic cardiomyopathy progressing to midcavitary obstruction and apical aneurysm development. A coronary angiogram showed no stenotic lesions in the epicardial coronary arteries and myocardial perfusion imaging showed no perfusion defects in the left ventricular apex, with the latter being an extremely uncommon finding. This case suggests that apical aneurysm may not be exclusively caused by ischemia and eventually different or coexisting factors are probably involved.
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PMID:Apical hypertrophic cardiomyopathy with midventricular obstruction and apical aneurysm. 1707 Sep 41

Physicians treating hypertrophic cardiomyopathy (HCM) are faced with unique management challenges. Understanding pathophysiology and overall good prognosis forms the basis for medical treatment. Treatment is tailored by the presence or absence of outflow tract gradient and individual symptoms. In all patients, formal stratification for sudden death risk is necessary, with consideration of defibrillator implantation in patients deemed to be at high risk. In patients with no or only mild symptoms the approach of watchful waiting is often appropriate. For symptomatic patients with non-obstructed disease medical treatment with calcium channel blockers and beta-blockers is aimed to improve heart failure symptoms, and ischemia. Verapamil is the most often used, with likely benefit of relieving ischemia. Obstruction, most commonly due to systolic anterior motion of the mitral valve (SAM) and mitral-septal contact, occurs in >/=50% of all HCM patients, worsening symptoms and increasing mortality. Successful medical treatment of obstruction with negative inotropes slows acceleration of left ventricular ejection with delay in SAM, ultimately yielding a lower pressure gradient. Beta -blockers are the first line treatment in obstructive HCM predominantly by mitigating provocable gradients. The magnitude of symptom relief with verapamil is similar to the effect of beta -blockade. Disopyramide combined with beta -blockade is thought by some to be the most effective medical treatment of obstruction, and has been shown to be safe and not pro-arrhythmic. Most symptomatic HCM patients with significant obstruction at rest or provocation can be successfully managed with long-term medication alone.
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PMID:Pathophysiology of hypertrophic cardiomyopathy determines its medical treatment. 1716 64

A 29-year old male was transferred to our hospital with an abnormal chest X-ray finding diagnosed as hypertrophic cardiomyopathy with apical necrosis and aneurysm formation. Four years after the initial hospitalization, we confirmed the aneurysm and necrosis using both integrated positron emission tomography (PET) and computed tomography (CT) scanning. The F-18 2-fluoro-2-deoxy-D-glucose (FDG) PET/CT enabled precise localization of the aneurysm, which was found to be composed of semi-lunar calcification of non-metabolic myocardium. A contrast-enhanced CT angiography showed an hour-glass appearance of the left ventricular cavity. The integrated PET/CT fusion scanner is a novel multimodality technology that allows for a comprehensive analysis of the anatomical and functional status of complex heart disease. Based on these findings, long standing mechanical and physiologic abnormalities may have led to chronic ischemia in the hypertrophied myocardium, induced necrosis and calcification at the cardiac apex.
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PMID:Hypertrophic cardiomyopathy complicated by left ventricular apical necrosis and aneurysm in a young man: FDG-PET findings. 1742 43

The prevalence of hypertrophic cardiomyopathy is estimated at 1:500 in the general population. Of these patients, approximately 1% develops midcavitary obstruction and subsequent apical aneurysm. We present a brief review of the literature on apical hypertrophic cardiomyopathy (HCM) using a rare case-based example. The etiology for apical aneurysm development is unclear but is thought to extend from apical fibrosis and necrosis secondary to subendocardial ischemia. The lifetime risk of cardiovascular death in patients with HCM is 2%. However, the risk may be higher in patients with apical aneurysms. Definitive therapy involves implantation of an automatic implantable cardioverter defibrillator, since medical therapy has variable success.
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PMID:Sustained ventricular tachycardia in apical hypertrophic cardiomyopathy, midcavitary obstruction, and apical aneurysm. 1754 15

The glutamic acid to lysine mutation at the 22nd amino acid residue (E22K) in the human cardiac myosin regulatory light chain (RLC) gene causes familial hypertrophic cardiomyopathy (FHC) with a phenotype of midventricular obstruction and septal hypertrophy. Our recent histopathology results have shown that the hearts of transgenic E22K mice (Tg-E22K) resemble those of human patients, demonstrating enlarged interventricular septa and papillary muscles. In this study, we show no effect of the E22K mutation on the kinetics of mutated myosin in its ATP-powered interaction with fluorescently labeled single actin filaments compared to nontransgenic or transgenic wild-type (Tg-WT) control mice. Likewise, no change in cross-bridge dissociation rates (g(app)) was observed in freshly skinned papillary muscle fibers. In contrast, maximal force and ATPase were decreased approximately 20% in Tg-E22K skinned papillary muscle fibers and intracellular [Ca2+] and force transients were significantly decreased in intact papillary muscle fibers from Tg-E22K compared to Tg-WT mice. Moreover, energy metabolism measured in isolated working Tg-E22K mouse hearts perfused under conditions of physiologically relevant levels of metabolic demand was similar in Tg-E22K and control hearts before and after 20 min of no-flow ischemia. Our results suggest that the pathological response observed in the E22K myocardium might be triggered by mutation induced changes in the properties of the RLC Ca2+-Mg2+ site, the state of the Ca2+/Mg2+ occupancy and consequently the Ca2+ buffering ability of the RLC. By decreasing the affinity of the RLC for Ca2+, the E22K mutation most likely promotes a Mg2+-saturated RLC producing less force and ATPase than the Ca2+-saturated RLC of WT fibers. Decreased Ca2+ binding may also lead to faster Ca2+ dissociation kinetics in Tg-E22K intact fibers resulting in decreased duration and amplitude of [Ca2+] and force transients. These changes when placed in vivo would result in higher workloads and consequently cardiac hypertrophy.
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PMID:Myosin regulatory light chain E22K mutation results in decreased cardiac intracellular calcium and force transients. 1760 8

Left ventricular outflow tract (LVOT) obstruction is a typical recognized feature in hypertrophic cardiomyopathy. However, it has been shown in other clinical scenarios such as acute ischemia. In some patients, LVOT obstruction may only be detectable with provocation testing such as exercise stress. Accurate and timely diagnosis, therefore, relies on recognizing an echocardiographic substrate in which LVOT obstruction may occur, such as ventricular hypertrophy. This report describes the case of a patient presenting with effort ECG and signs of myocardial ischemia, with no significant narrowing of coronary arteries but with latent LVOT obstruction due to the presence of an abnormal hypertrophic papillary muscle instead of a typical ventricle hypertrophy.
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PMID:Latent left ventricular outflow tract obstruction induced by abnormal hypertrophic papillary muscle caused myocardial ischemia. 1804 13


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