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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To study the role of catecholamines in the pathogenesis of hypertrophic cardiomyopathy (HCM), hemodynamic responses to low and high dose infusions of epinephrine (0.037 and 0.074 micrograms/Kg/min) were compared between 21 patients with nonobstructive HCM and 21 healthy controls, matched for age and sex. During low dose infusion, patients with HCM showed significantly greater responses (p less than 0.05) than controls in echocardiographic left ventricular (LV) end-systolic dimension (-8 +/- 1% vs -4 +/- 1%, mean +/- SEM), fractional shortening (12 +/- 2% vs 7 +/- 1%) and peak systolic velocity of the LV posterior wall (32 +/- 5% vs 15 +/- 4%), but the differences disappeared during high dose infusion. Thus, patients with HCM started to respond to epinephrine earlier than controls and seemed to have an increased sensitivity of beta-adrenergic receptors in the cardiovascular system. As the augmented responses were more evident in younger patients (less than 35 years) who manifested frequent familial occurrences of HCM, the increased sensitivity to catecholamine was postulated to be genetically determined and to be related to the abnormal myocardial hypertrophy of HCM.
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PMID:Increased cardiovascular response to epinephrine in hypertrophic cardiomyopathy. 408 67

Restrictive cardiomyopathy is rare in childhood and little is known about the causes and outcome. This lack of information results in extrapolation of adult data to the care and management of children, who might require different treatment from that of adults. This study was undertaken retrospectively to evaluate the causes and natural history of restrictive cardiomyopathy in childhood. Twelve cases of restrictive cardiomyopathy were identified by database review of patient records from 1967 to 1994. The cases were selected on the basis of echocardiographic and cardiac catheterization criteria. Charts were reviewed for the following variables: age, sex, cause, right-and left-sided hemodynamics, pulmonary vascular resistance index, shortening fraction, therapy, and outcome. There were 6 males and 6 females with a mean age of 4.6 years at presentation (median, 3.4 yr; range, 0.9 to 12.3 yr). Etiologies included hypertrophic cardiomyopathy in 3 patients, cardiac hypertrophy with restrictive physiology in 3, idiopathic in 2, familial in 2 (twins), "chronic eosinophilia" in 1, and "post inflammatory" with no definitive causes in 1. At presentation the mean shortening fraction was 33% +/- 2% (mean +/- SEM), average right ventricular pressures were 44/13 +/- 3/1, average left ventricular pressures were 88/25 +/- 4/3, and the mean pulmonary vascular resistance index was 3.4 +/- 1.3 U.m2 (n = 9), but increased to 9.9 +/- 3.1 U.m2 (n = 5, p = 0.04) by 1 to 4 years after diagnosis. Four of the 12 patients had embolic events (1, recurrent pulmonary emboli; 1, saddle femoral embolus; 2, cerebrovascular accidents) and 9 of 12 died within 6.3 years despite medical therapies, which included diuretics, verapamil, propranolol, digoxin, and captopril. In conclusion, restrictive cardiomyopathy in childhood is commonly idiopathic or associated with cardiac hypertrophy, and the prognosis is poor. Embolic events occurred in 33% of our patients, and 9 of 12 patients died within 6.3 years. Within 1 to 4 years of diagnosis, patients may develop a markedly elevated pulmonary vascular resistance index; therefore, transplantation should be considered early.
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PMID:Restrictive cardiomyopathies in childhood. Etiologies and natural history. 906 38

1. There is controversy regarding plasma catecholamine levels in patients with hypertrophic cardiomyopathy (HCM) and few data exist on serial plasma catecholamine measurements during exercise. The present study determined whether cardiovascular and plasma catecholamine responses to exercise were altered in patients with HCM. 2. Plasma noradrenaline (NA) and adrenaline were measured at rest, at the end of each stage during exercise and immediately and 5 min after submaximal treadmill exercise in 15 patients with non-obstructive HCM (13 males, two females; mean (+/- SEM) age 54 +/- 3 years) and in 15 age- and sex-matched controls. The ratio of the increment in heart rate (HR) divided by the increment in plasma NA during exercise (delta HR/delta NA) was used as an index of chronotropic sympathetic responsiveness to exercise. 3. Exercise duration was shorter (11.2 +/- 0.6 vs 8.7 +/- 0.6 min for control vs HCM, respectively; P < 0.01) and diastolic blood pressure was significantly higher at stages I and II of modified Bruce protocol HCM. 4. Resting plasma NA levels (149 +/- 17 vs 167 +/- 28 pg/mL for control vs HCM, respectively; NS) were not different, but plasma NA levels at stages I and II were significantly higher in HCM than in controls (243 +/- 26 vs 399 +/- 69 pg/mL (P < 0.05) and 308 +/- 30 vs 548 +/- 110 pg/mL (P < 0.05), respectively). 5. Peak plasma NA levels were not significantly higher in HCM than in controls (578 +/- 59 vs 918 +/- 184 pg/mL, respectively; NS). 6. The ratio delta HR/delta NA was significantly lower in HCM compared with control at stages I and II (0.49 +/- 0.10 vs 0.21 +/- 0.05 (P < 0.05) and 0.38 +/- 0.06 vs 0.20 +/- 0.05 (P < 0.05), respectively). There were no differences in plasma adrenaline responses during exercise between the two groups. 7. Patients with HCM had augmented plasma NA levels during submaximal exercise with a higher diastolic blood pressure response. Chronotropic sympathetic responsiveness was impaired during the early stages of exercise in patients with HCM.
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PMID:Augmented exercise plasma noradrenaline with impaired chronotropic responsiveness in patients with hypertrophic cardiomyopathy. 988