The American journal of cardiology
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To evaluate, in right ventricular (RV) myocardial infarction, the role of tricuspid regurgitation (TR) and left ventricular (LV) damage and the response to treatment of low cardiac output, 20 patients were prospectively studied. Volume infusion increased cardiac output only slightly (11%, p less than 0.001), despite a dramatic increase in ventricular filling pressures. Dobutamine (4 micrograms.kg-1.min-1) markedly increased cardiac output (24%, p less than 0.001) with a decrease in ventricular filling pressures. ⋯ All patients with RV infarction-induced low cardiac output responded only modestly to volume loading. Dobutamine is particularly efficacious in patients without TR who have depressed LV function by improving RV function and, consequently, LV preload. In the 5 patients with TR, increasing RV contractility failed to improve the forward stroke volume by increasing the regurgitant fraction.
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Previous studies evaluating the incidence of patent ductus arteriosus have not made a distinction between physiologic ductal patency and abnormally persistent ductus arteriosus. However, it has recently been shown that healthy premature infants without respiratory distress syndrome (RDS) undergo spontaneous closure of the ductus arteriosus in the first 4 days of life at times comparable to full-term infants. Thus, ductal patency within this time frame would appear to be physiologic. ⋯ By the fourth day of life, only 4 of 36 (11.1%) of the infants continued to have evidence of ductal patency. The remainder of the infants underwent spontaneous functional closure of the ductus arteriosus at times comparable to healthy infants without RDS. For most infants greater than or equal to 30 weeks gestation, uncomplicated RDS does not alter the usual timing of functional ductal closure.
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Transesophageal echocardiography (horizontal sector scan) was performed in 11 patients with secundum atrial septal defect (ASD). In all 11 patients, transesophageal echocardiography presented the definite visualization of the defect and a clear laminar shunt flow that showed its 2 peaks in late systole and late diastole. We estimated the size of ASD and a shunt volume across the defect by using transesophageal echocardiography. ⋯ Thus, transesophageal echocardiography is a useful method in evaluation of the defect size and the shunt flow volume of ASD. The mean shunt flow velocity was not a reliable index for estimating the shunt flow volume. The defect size might be a valuable determinant of left-to-right shunt volume in ASD.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparative evaluation of a new formulation of isosorbide dinitrate oral spray and sublingual nitroglycerin tablets.
The magnitude and time course of the hemodynamic effect of a new formulation of an aqueous solution of isosorbide dinitrate (ISDN) spray were compared with those of sublingual nitroglycerin (NTG) tablets in 12 patients with chronic congestive heart failure. The patients received, in a random order, ISDN spray, 2.5 mg, or sublingual NTG, 0.8 mg. Hemodynamic measurements were performed before and at 1, 3, 5, 10, 20, 30 and 60 minutes after each drug. ⋯ The peak effect of ISDN spray on PCWP and right atrial pressure was greater than that of NTG. Thus, the onset of the hemodynamic effect of the new formulation of ISDN spray is much more rapid than that of sublingual NTG tablets. At the doses used, the magnitude of the effect of the ISDN spray on some of the hemodynamic variables is greater than that of sublingual NTG.