Journal of the American College of Cardiology
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J. Am. Coll. Cardiol. · Mar 1993
Comparative StudyMeasurements of cardiac output by impedance cardiography in pacemaker patients at rest: effects of various atrioventricular delays.
The purpose of this study was to evaluate the ability of impedance cardiography to determine the change in cardiac output caused by modifications in the atrioventricular (AV) delay in DDD (dual-chamber) pacing mode while pacing the atrium and ventricle at different programmed rates. ⋯ 1) Impedance cardiography allows highly reproducible noninvasive assessments of cardiac output in pacemaker patients; 2) inappropriate programming of the AV interval in patients with atrial and ventricular pacing can decrease cardiac output significantly, and the extent of the decrease is similar to or less than that observed in ventricular pacing; 3) hemodynamic measurements obtained with impedance cardiography can facilitate optimal programming of pacemaker variables.
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J. Am. Coll. Cardiol. · Mar 1993
Discordance in degree of right and left ventricular dilation in patients with dilated cardiomyopathy: recognition and clinical implications.
The purpose of the present study was to assess the influence of variations in the relative degree of dilation of left and right ventricular chambers on the clinical outcome of patients with dilated cardiomyopathy. ⋯ Patients with dilated cardiomyopathy represent a heterogeneous group with regard to both clinical outcome and the relative degree of left and right ventricular chamber dilation. Patients in the LV > RV subset appear to have better overall survival and less severe mitral and tricuspid regurgitation than do patients in the LV congruent to RV subset. Longitudinal studies are needed to determine whether these morphologic subsets in fact represent a continuum within the disease spectrum of dilated cardiomyopathy.
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J. Am. Coll. Cardiol. · Mar 1993
Pulmonary and peripheral vascular factors are important determinants of peak exercise oxygen uptake in patients with heart failure.
This study was conducted to determine the relations among exercise capacity and pulmonary, peripheral vascular, cardiac and neurohormonal factors in patients with chronic heart failure. ⋯ In comparison with rest indexes of cardiac performance, measures of pulmonary function and peripheral vasodilator capacity were more closely associated with peak exercise oxygen uptake in patients with heart failure. Furthermore, the associations were independent of each other and together accounted for 50% of the variance in peak oxygen uptake. These data suggest that pulmonary and peripheral vascular adaptations may be important determinants of exercise intolerance in heart failure.
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J. Am. Coll. Cardiol. · Mar 1993
Prognostic implications of myocardial ischemia during daily life in low risk patients with coronary artery disease.
The purpose of this study was to determine the incidence and prognostic importance of myocardial ischemia detected by ambulatory monitoring in low risk, medically managed patients with coronary artery disease. ⋯ In patients categorized as at low risk on the basis of the results of cardiac catheterization and stress testing, silent myocardial ischemia during daily life was not uncommon, and its presence failed to predict future coronary events.
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J. Am. Coll. Cardiol. · Mar 1993
Which subgroup of patients with dilated cardiomyopathy would benefit from long-term beta-blocker therapy? A histologic viewpoint.
The purpose of this study was to elucidate whether the effectiveness of long-term beta-blocker therapy could be predicted before this therapy is started. ⋯ The extent and type of fibrosis may be important factors in the prediction of the effectiveness of long-term beta-blocker therapy for dilated cardiomyopathy.