The cardiac output was measured simultaneously by the impedance cardiography and dye dilution methods in 10 patients with acute myocardial infarction 2-3 weeks after admission to the Coronary Care Unit. The impedance cardiac output was on the average 9.7% higher than the dye dilution cardiac output. The reproducibility of impedance cardiac output 4.1%, compared with 5.1% for the dye dilution method. The study showed a satisfactory reliability of impedance in predicting the relative changed of cardiac output in response to tilting from the supine to the 30 degrees head-up position, to a 10 degrees head-down position, and to the intravenous administration of propranolol.
Summary:Changes in transthoracic electrical impedance (TEI) were recorded in 20 patients with acute myocardial infarction before, during, and 60 min after intravenous administration of furosemide (Impuganm). The major change was an increase in TEI (ZO) (6.2%, p0.05). Heart rate and blood pressure remained unchanged. It was possible to differentiate between two types of TEI changes after furosemide. In 10 patients there was an early and rapid increase in ZO (type A), while the rest of the patients showed a decreased or unchanged ZO followed by a slow increase (type-B). The line describing the mean ZO change in type A was significantly higher than that of type B and fell outside f 2 SEM of the line describing the mean ZO change found in five normal subjects (type C). The ZO change in type B was similar to that in type C. It is assumed that Z , change in type A may represent patients with an increased amount of extravascular fluid (heart failure), while the change in type B represents patients without heart failure. This assumption is based on the difference in dependency of TEI on extravascular volume versus intravascular volume changes. It is suggested that the impedance method may be used as a simple noninvasive method to assess the effect of diuretic therapy and may have the value of detecting extravascular thoracic fluids in acute myocardial infarction.
Abstract. Twenty‐four patients with chronic lung disease have been examined by means of right heart catheterization to investigate the level of the pressure difference between the pulmonary artery diastolic pressure and the mean pulmonary artery wedge pressure (PPAd ‐ P̄w) and its relation to the pulmonary vascular resistance at rest and during exercise. In patients who had a normal pulmonary vascular resistance (PVR < 3 units), there was no significant pressure difference either at rest or during exercise when P̄w was 6–27 mmHg, while in patients with increased pulmonary resistance (PVR > 3 units) a significant pressure difference has been found. A pressure difference between 4 and 5 mmHg was found, in the present material, to be an index for differentiation between a normal and an increased vascular resistance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.