Circulation
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Randomized Controlled Trial Clinical Trial
Starting aspirin therapy after operation. Effects on early graft patency. Department of Veterans Affairs Cooperative Study Group.
Although aspirin therapy started before operation improves vein graft patency after coronary artery bypass grafting, it also causes bleeding. The objective of this prospective, centrally directed, randomized, double-blind, placebo-controlled trial was to compare the effects of aspirin therapy started before operation with aspirin started 6 hours after operation on early (7-10-day) graft patency. ⋯ Thus, preoperative aspirin is associated with increased bleeding complications and offers no additional benefit in early vein graft patency compared with starting aspirin therapy 6 hours after operation. There was a trend, although not significant, toward improved early patency for Y grafts and internal mammary artery grafts with preoperative aspirin.
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Long QT syndrome (LQTS) is a congenital disorder accompanied by a high incidence of sudden cardiac death. beta-Adrenergic blockade is the therapy of choice, and it is successful in 75-80% of patients. For those in whom cardiac events (syncope or cardiac arrest) are not prevented by beta-blockade, experimental studies suggest that left cardiac sympathetic denervation (LCSD) may be useful. ⋯ The present findings demonstrate that for LQTS patients who continue with syncope or cardiac arrest despite the use of beta-blockers, LCSD is a very effective therapy.
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Comparative Study
Doppler and echocardiographic characteristics of patients having an Austin Flint murmur.
The purpose of this study was to investigate the genesis of the Austin Flint murmur using Doppler and echocardiographic imaging. ⋯ The results of this study suggest that the primary factor responsible for the Austin Flint murmur is the presence of an aortic insufficiency jet directed at the anterior mitral leaflet. This, combined with the biphasic pattern of transmitral flow, distorts the shape of the anterior mitral leaflet as it opens and closes during diastole, making it shudder. The leaflet's shuddering sets up vibrations and shock waves that distort the aortic insufficiency jet, causing the observed Doppler striations and probably the sound of the murmur. There is no evidence from this study to support prior theories that have proposed functional mitral stenosis or diastolic mitral regurgitation as the source of the murmur.
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The complete continuous-wave Doppler mitral regurgitant velocity curve should allow reconstruction of the ventriculoatrial (VA) pressure gradient from mitral valve closure to opening, including left ventricular (LV) isovolumic contraction, ejection, and isovolumic relaxation. Assuming that the left atrial pressure fluctuation is relatively minor in comparison with the corresponding LV pressure changes during systole, the first derivative of the Doppler-derived VA pressure gradient curve (Doppler dP/dt) might be used to estimate the LV dP/dt curve, previously measurable only at catheterization (catheter dP/dt). ⋯ The present study demonstrated an accurate and reliable noninvasive Doppler method for estimating instantaneous LV dP/dt, dP/dtmax, and -dP/dtmax.
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Background. The gas nitric oxide (NO) is an important endothelium-derived relaxing factor, inactivated by rapid combination with heme in hemoglobin. Methods and Results. ⋯ Breathing 80 ppm NO for 3 hours did not increase either methemoglobin or extravascular lung water levels nor modify lung histology compared with control lambs. Conclusions. Low dose inhaled NO (5-80 ppm) is a selective pulmonary vasodilator reversing both hypoxia- and thromboxane-induced pulmonary hypertension in the awake lamb [corrected].