Circulation
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Several studies performed before the advent of thrombolysis have shown that the presence of ventricular arrhythmias is an independent risk factor for subsequent mortality in patients recovering from acute myocardial infarction. Since fibrinolysis affects the natural history of infarction and may alter the clinical relevance of different risk factors, the aim of the present study was to establish the prevalence and prognostic value of ventricular arrhythmias in post-myocardial infarction patients treated with fibrinolytic agents during the acute phase. ⋯ This study shows that approximately 36% of patients recovering from acute myocardial infarction presented with less than one premature ventricular beat per hour in Holter recordings obtained before discharge from the hospital, whereas almost 20% of patients showed frequent (more than 10 premature ventricular beats per hour) ventricular arrhythmias. Due to the large size of the population of this study, these figures may be used as a reliable estimate of the prevalence of arrhythmias in postinfarction patients treated with fibrinolytic agents during the acute phase. Frequent premature ventricular beats are confirmed as independent risk factors of total and sudden death in the first 6 months following the acute event; the significance of nonsustained ventricular tachycardia in this population appears more controversial.
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Congenital heart lesions may be complicated by pulmonary arterial smooth muscle hyperplasia, hypertrophy, and hypertension. We assessed whether inhaling low levels of nitric oxide (NO), an endothelium-derived relaxing factor, would produce selective pulmonary vasodilation in pediatric patients with congenital heart disease and pulmonary hypertension. We also compared the pulmonary vasodilator potencies of inhaled NO and oxygen in these patients. ⋯ Inhaled NO is a potent and selective pulmonary vasodilator in pediatric patients with congenital heart disease complicated by pulmonary artery hypertension. Inhaling low levels of NO may provide an important and safe means for evaluating the pulmonary vasodilatory capacity of patients with congenital heart disease without producing systemic vasodilation.
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Case Reports
Augmentation of coronary blood flow by intra-aortic balloon pumping in patients after coronary angioplasty.
Controversy exists regarding the ability of intra-aortic balloon pumping to increase coronary blood flow in patients with obstructive coronary artery disease. To assess the effects of intra-aortic balloon pumping on coronary hemodynamics, we measured coronary blood flow velocity with a 0.018-in. Doppler-tipped angioplasty guide wire in 15 patients who received an intra-aortic balloon pump for typical clinical indications. ⋯ These data demonstrate lack of significant flow improvement beyond most critical stenoses with intra-aortic balloon pumping and the unequivocal restoration and intra-aortic balloon pump-mediated augmentation of both proximal and distal coronary blood flow velocities after amelioration of severe coronary obstructions in patients after successful coronary angioplasty.
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Although postprandial hypotension is a common cause of falls and syncope in elderly persons and in patients with autonomic insufficiency, the pathophysiology of this disorder remains unknown. ⋯ 1) In healthy elderly subjects, the maintenance of blood pressure homeostasis after food ingestion is associated with an increase in HR, forearm vascular resistance, cardiac index, and plasma NE. In both young and old, systemic vascular resistance is maintained. 2) Dysautonomic patients with postprandial hypotension fail to maintain systemic vascular resistance after a meal. This impairment in vascular response to meal ingestion may underlie the development of postprandial hypotension. 3) The measurement of mean HR or plasma NE does not adequately characterize autonomic cardiac control. Power spectral analysis suggests an impairment in the postprandial autonomic modulation of HR in healthy elderly and dysautonomic subjects, possibly predisposing to hypotension when vascular compensation is inadequate.
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Arrhythmias are a significant source of morbidity and mortality in patients with congenital heart defects. ⋯ The prevalence of arrhythmias (especially ventricular arrhythmias) was higher for patients with aortic stenosis, pulmonary stenosis, or ventricular septal defect than for an historical control population. "Serious arrhythmias" were most frequently noted in patients with aortic stenosis who also had a higher incidence of sudden death. The prevalence of "serious arrhythmias" was second highest for patients with ventricular septal defect who had the second highest incidence of sudden death.