Circulation
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The amount of cross-sectional area narrowing by atherosclerotic plaque in each 5-mm-long segment from the entire lengths of the right, left main, left anterior descending and left circumflex coronary arteries and the size, predominant location and extent of myocardial scarring were determined in 59 necropsy patients with a healed transmural myocardial infarct (MI). The mean number of the four major epicardial coronary arteries narrowed severely (76-100% in cross-sectional area) was 3.0 in the 37 patients with posterior MI and 2.6 in the 22 patients with anterior MI (p less than .025). ⋯ The patients with posterior MI had a higher percentage of severely narrowed segments of the right and left circumflex coronary arteries than of the left anterior descending artery, 55% and 51% vs 32% (p less than 0.05). The anterior MI group had, on the average, larger left ventricular scars than the posterior MI group (20% vs 9%, p greater than 0.002) and more frequent scarring of the ventricular septum, 16 patients (73%) vs six patients (16%) (p less than 0.001).
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Comparative Study
Regional myocardial hemodynamic and metabolic effects of ionic and nonionic contrast media in normal and ischemic states.
The effects of intracoronary injection of two nonionic contrast media (iohexol and metrizamide) on myocardial contraction and chemical composition of coronary sinus (CS) blood were compared with those caused by the standard ionic contrast material for coronary angiography, sodium meglumine diatrizoate (R76), in 14 anesthetized dogs. The effects of each agent on regional contractility were compared in the normal state and in the presence of a critical coronary artery stenosis. The three contrast media produced equivalent decreases in hematocrit and sodium (both NS), but R76 caused a greater increase in CS osmolality (p less than 0.02). ⋯ The effects of the nonionic agents were similar in both normal and diseased states. We conclude that nonionic contrast media produce fewer alterations than ionic contrast media in coronary sinus blood chemistry and myocardial contractile state. The effect of ionic contrast media on regional contraction is accentuated in the presence of coronary artery stenosis.
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Randomized Controlled Trial Clinical Trial
Acute hemodynamic responses to sublingual nifedipine: dependence on left ventricular function.
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Phosphorus-31 nuclear magnetic resonance (31P NMR) can estimate tissue intracellular pH as well as the content of high-energy phosphate metabolites in isolated perfused hearts. We used 31P NMR to examine mechanisms associated with the recovery of ventricular function in hearts subjected to global ischemia and reperfusion, with special emphasis on intracellular pH, a previously unreported variable. Single-dose and multiple-dose administration of a hyperkalemic cardioplegic solution were compared with hypothermia alone in 18 isolated perfused rabbit hearts. ⋯ These results demonstrate that the magnitude of intracellular acidosis and the associated increase in inorganic phosphate correlate inversely with recovery of postischemic ventricular structure and function. ATP, but not creatine phosphate, content correlates with return of contractile performance after reperfusion. The overshoot in creatine phosphate during early reperfusion might impede optimal restoration of ATP content and, as a result, optimal recovery of cell functions.
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The clinical and morphologic features of hypertrophic cardiomyopathy in 20 patients recognized as having cardiac disease in the first year of life are described. Fourteen of these 20 infants were initially suspected of having heart disease solely because a heart murmur was identified. However, the infants showed a variety of clinical findings, including signs of marked congestive heart failure (in the presence of non-dilated ventricular cavities and normal or increased left ventricular contractility) and substantial cardiac enlargement on chest radiograph. ⋯ Ventricular septal thickening was substantial in patients studied both before and after 6 months of age (mean 16 mm), indicating that in patients with hypertrophic cardiomyopathy, marked left ventricular hypertrophy may be present early in life and is probably congenital. The clinical course was variable in these patients, but the onset of marked congestive heart failure in the first year of life appeared to be an unfavorable prognostic sign; nine of the 11 infants with congestive heart failure died within the first year of life. In infants with hypertrophic cardiomyopathy, unlike older children and adults with this condition, sudden death was less common (two patients) than death due to progressive congestive heart failure.