The American journal of cardiology
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Comparative Study
Normal left ventricular emptying in coronary artery disease at rest: analysis by radiographic and equilibrium radionuclide ventriculography.
The volume ejected early in systole has been proposed as an indicator of abnormal left ventricular function that is present at rest in patients with coronary artery disease with a normal ejection fraction and normal wall motion. The volume ejected in systole was examined by calculating the percent change in ventricular volume using both computer-assisted analysis of biplane radiographic ventriculograms at 60 frames/s and equilibrium gated radionuclide ventriculograms. Ventricular emptying was examined with radiographic ventriculography in 33 normal patients and 23 patients with coronary artery disease and normal ejection fraction. ⋯ In all patients, there was excellent correlation between the radiographic and radionuclide ventricular emptying curves (r = 0.971). There were no difference in the ventricular emptying curves of normal subjects and patients with coronary artery disease whether volumes were measured by radiographic or equilibrium gated radionuclide ventriculography. It is concluded that the resting ventricular emptying curves are identical in normal subjects and patients with coronary artery disease who have a normal ejection fraction and normal wall motion.
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Lorcainide, a new class I antiarrhythmic drug, was administered intravenously to 10 patients with a documented history of ventricular arrhythmias. Three patients had arrhythmias resistant to all conventional antiarrhythmic drugs; in all other patients except one, previous antiarrhythmic drug therapy had to be discontinued because of poor efficacy or unacceptable adverse effects. Lorcainide was injected in incremental doses of 25 mg every 15 minutes and a dose of 182.4 +/- 26.5 mg (mean +/- standard deviation) of the drug was given. ⋯ The plasma half-life ranged from 6.2 to 23.1 hours (mean 13.1 +/- 5.0). Three patients are currently being treated orally with lorcainide. These data suggest that lorcainide is an effective antiarrhythmic drug with desirable pharmacokinetic properties, and long-term definitive studies are recommended.
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The mechanical factors by which chronic respiratory insufficiency may influence right and left ventricular performance during both spontaneous and mechanical ventilation are reviewed. During a spontaneous inspiration the right heart distends because of increased inflow and increased pulmonary vascular resistance. This decreases the effective left ventricular compliance, through ventricular interdependence, reducing the gradient for pulmonary venous return. ⋯ This increased inspiratory flow cannot be attributed to a phase lag in the right heart output reaching the left heart chambers because, even with a constant pulmonary arterial inflow, aortic flow increases during inspiration. Several factors may act in concert to improve left ventricular performance, despite the adverse effects of intermittent positive pressure ventilation on the right ventricle. These include (1) a decrease in right heart volume, increasing left ventricular compliance and hence the gradient for pulmonary venous return; (2) anterograde emptying of the alveolar capillary bed with lung inflation; (3) the increase in pleural pressure decreasing impedance to left ventricular emptying; and (4) physical compression of the heart by the lungs.
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Although stenosis and infective endocarditis are commonly appreciated complications of the congenitally bicuspid aortic valve, pure severe aortic regurgitation complicating this congenital malformation, unassociated with either stenosis or infection, is not well recognized. Among 189 patients who had aortic valve replacement at the National Heart, Lung, and Blood Institute because of isolated pure aortic regurgitation, the congenitally bicuspid aortic valve, never the site of infective endocarditis, was responsible for the aortic regurgitation in 13 (7 percent). This report describes certain clinical and morphologic findings in 13 men, aged 26 to 65 years (mean 43), who required aortic valve replacement because of severe aortic regurgitation secondary to a noninfected, nonstenotic congenitally bicuspid aortic valve. Although not generally recognized, the noninfected congenitally bicuspid aortic valve is an important cause of pure aortic regurgitation severe enough to warrant aortic valve replacement.
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A new single chambered percutaneous intraaortic balloon has been constructed around a central guidewire. The balloon can be wrapped around the guidewire, enabling its insertion into the femoral artery through a 12F sheath inserted with the conventional Seldinger technique. Percutaneous intraaortic balloon insertion has been performed in 27 patients (mean age 58 years) for a variety of medical and surgical indications. ⋯ After direct balloon removal, external pressure was applied for 30 minutes. No patient experienced hematoma of the groin, aortic dissection, compromised distal pulses or late wound complications. Percutaneous balloon insertion permits the rapid institution of circulatory support and broadens the medical and surgical applications of intraaortic balloon pumping.