Cooling of the working rat heart to 30ï¿½C caused an increase in stroke volume and peak systolic pressure while the heart rate decreased. The mean aortic flow decreased at 30ï¿½C, in the presence of 2,5 and 1,25 mM CaCI2, but increased by 29% at 0,63 mM CaCI2. Power output increased by 48% at 0,63 mM CaCI2, but decreased at 2,5 and 1,25 mM CaCI2. At constant preload, isotonic contraction of isolated papillary muscle and Langendorff perfused hearts increased, respectively, by 37% and 43% at 0,63 mM CaCI2. It can therefore be concluded that preload-independent increase in power output is a major determinant of the working heart's higher aortic output at 30ï¿½C, 0,63 mM CaCI2; and also that at a Ca2+ concentration of less than 1 mM the product of stroke volume and heart rate is such that cardiac output of the isolated working rat heart is higher at 30ï¿½C than at 37ï¿½C.
Exercise scintigraphy with technetium-99m sestamibi is documented to be able to detect coronary artery disease with a high degree of accuracy. Dipyridamole scintigraphy is available for those patients who are unable to exercise. In order to assess the degree of agreement between dipyridamole and exercise scintigraphy, 11 patients with angiographically documented coronary disease underwent tomographic myocardial perfusion imaging with 99mTc sestamibi at rest, after a symptom-limited treadmill exercise test and after intravenous dipyridamole. Myocardial images after intravenous infusion of dipyridamole and after exercise were compared with rest images and the results were interpreted in relation to angiographic data.
Patients with atrioventricular septal defects (AVSDs) are prone to develop pulmonary vascular obstructive disease (PVOD) in infancy earlier than similar patients with ventricular septal defects (VSDs) or atrial septal defects (ASDs). It was hypothesised that this would be reflected in prehilar pulmonary artery hyperplasia. Review of the catheterisation data and angiograms of 34 consecutive patients with AVSD under 1 year of age who underwent repair at our institution was undertaken, and the results compared with 10 patients with secundum-type ASDs and 10 patients with perimembranous VSDs who were matched for age, size and intercardiac shunt ratio (Qp:Qs).
Infective endocarditis (IE) has high mortality and morbidity rates despite available treatment. Because of the changing predisposing cardiac abnormalities and causative organisms, a retrospective study of 29 children with this disease was undertaken to review our experience in its diagnosis and treatment. Forty-eight per cent of the patients presented with the classic clinical picture of IE. Rheumatic heart disease (69%) was the most common underlying cardiac condition. Sixty-five per cent of the blood cultures were negative, possibly because 82,5% of patients received antibiotic treatment before being referred to our institution.
A 60-year-old woman with tricuspid and pulmonary regurgitation occurring in association with carcinoid syndrome is reported. The carcinoid tumour was localised to a dermoid cyst of the ovary and was successfully removed at surgery. Diarrhoea, palpitations and elevated 5-hydroxy-indole acetic acid (5HIAA) levels, present at the time of presentation, regressed following tumour resection. Echocardiography showed the tricuspid and pulmonary valves to have thickened cusps held permanently in the open position.