Journal of the American College of Cardiology
-
J. Am. Coll. Cardiol. · Mar 1993
Randomized Controlled Trial Comparative Study Clinical TrialNoninvasive assessment of the direct action of oral nifedipine and nicardipine on left ventricular contractile state in patients with systemic hypertension: importance of reflex sympathetic responses.
This study was designed to noninvasively assess the direct action of calcium channel blockers on left ventricular contractility in humans and to establish a framework for determining the importance of reflex sympathetic responses to any pharmacologic intervention. ⋯ Totally noninvasive techniques showed a differential effect on left ventricular contractility between nifedipine and nicardipine when alterations in afterload and reflex sympathetic responses were eliminated as confounding variables. This diagnostic approach, based on the use of pharmacologic probes, should have wide applicability for assessing the direct inotropic effect of any agent, even in the presence of complex primary and secondary physiologic modes of action.
-
J. Am. Coll. Cardiol. · Mar 1993
Dobutamine stress echocardiography predicts surgical outcome in patients with an aortic aneurysm and peripheral vascular disease.
This study was conducted to assess the utility of dobutamine stress echocardiography for determining the presence of significant coronary artery disease and for predicting surgical outcome and long-term prognosis in patients scheduled to undergo peripheral vascular or aortic aneurysm surgery. ⋯ Positive and negative dobutamine study results are significant predictors of the presence or absence of perioperative events (20% vs. 0%, p = 0.003). A positive test warrants coronary angiography and further medical or surgical intervention, or both, but a negative test indicates a low likelihood of perioperative cardiac complications of aortic or peripheral vascular surgery. During the long-term follow-up period in this study (group 1 mean, 24 months; group 2 mean, 15 months), two patients (3%) from group 1 and three (15%) from group 2 developed cardiac complications (p = 0.038). Thus, dobutamine stress echocardiography is safe and can predict surgical outcome in patients undergoing aortic aneurysm repair or surgery for occlusive disease of the peripheral arteries. In addition, a negative test result is a strong predictor of decreased perioperative and long-term cardiac morbidity and mortality.
-
J. Am. Coll. Cardiol. · Mar 1993
Response of the interatrial septum to transatrial pressure gradients and its potential for predicting pulmonary capillary wedge pressure: an intraoperative study using transesophageal echocardiography in patients during mechanical ventilation.
We hypothesized that the directional movement of the interatrial septum and its curvature may reflect the pressure relations between the left and right atria. ⋯ These findings suggest that overall interatrial septum shape depends on the pressure gradient between the left and right atria. Midsystolic reversal of the interatrial septum, which probably reflects the increased venous return in the right relative to the left atrium during mechanical expiration, may be a useful indicator of the pulmonary capillary wedge pressure.
-
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.