Biomedical subjects
H J Swan
Publications and source records attributed to H J Swan.
The rt-PA versus streptokinase controversy--IV.
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The pulmonary artery catheter.
First developed more than 20 years ago as a research tool for investigations of myocardial infarction, the pulmonary artery or Swan-Ganz catheter has gained general usage as a valuable clinical tool. Its development paralleled the rapid growth of technological advancements in clinical medicine. Rapid incorporation of technological advancements into clinical practice, however, is not without risk. Care must be taken to assure that clinicians possess the understanding of both basic concepts and requisite hardware to provide quality patient care. Equipment selection and calibration, patient selection, data interpretation, potential complications, troubleshooting, and procedure limitations must all be considered. Broader application of the Swan-Ganz catheter in surgery, anesthesiology, and critical care as well as in cardiology has provided information on hemodynamics that has had considerable impact on diagnostics as well as on therapy for patients with a wide variety of clinical conditions.
New method for monitoring pulmonary artery catheter location.
OBJECTIVE: To test the ability of a modified pulmonary artery (PA) monitoring catheter to detect distal catheter migration. DESIGN: Prospective nonrandomized trial. PATIENTS: Surgical ICU patients requiring invasive hemodynamic monitoring. INTERVENTIONS: Eight patients received PA catheters modified to include a right ventricular (RV) pressure monitoring port located 7 cm from the tip. Fifteen patients received catheters with an RV port located 10 cm from the tip. Guided by the RV port pressure waveform, catheters were initially positioned so that the RV port was located just proximal to the pulmonic valve. MEASUREMENTS AND MAIN RESULTS: Pulmonary capillary occlusion pressure (PAOP) could not be obtained in six of the eight patients receiving the 7-cm RV port catheter unless the RV port was advanced into the PA. PAOP was consistently obtained in all 15 patients receiving the 10-cm RV port catheter, with the RV port positioned in the RV. Chest radiographs confirmed a central PA catheter position. In this group, distal migration of the catheter occurred 14 times in eight patients, as detected by appearance of a PA pressure waveform at the RV port. Distal migration was corrected by withdrawal of the catheter until an RV waveform reappeared at the RV port. CONCLUSIONS: We conclude that distal catheter migration occurs frequently with PA monitoring catheters, but can be detected at the bedside with a catheter modified to include an RV port 10 cm from the tip. This new catheter may add a margin of safety to PA monitoring and lower its overall cost by eliminating the need for chest radiographs ordered solely to confirm catheter tip location.
Enoximone in chronic heart failure.
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Thrombocytopenia and fever in a patient taking amrinone.
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Hemodynamic monitoring: a personal and historical perspective.
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[Left ventricular function in the first 24 hours of acute transmural myocardial infarction (author's transl)].
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Photokymography: a noninvasive method of detecting ischemic segmental myocardial wall motion abnormalities.
The photokymograph is a new and simple noninvasive device for assessing epicardial segmental myocardial wall motion utilizing cardiac fluoroscopy and image intensification. The validity of this technique in detecting wall motion changes occurring with ischemia was assessed in seven closed chest dogs undergoing acute balloon occlusion of the left circumflex coronary artery. Acute occlusion resulted in a prompt change in the analog signal of the photokymogram, characterized first by a decreased systolic inward motion and late systolic outward movement that later became akinetic and dyskinetic. Systolic amplitude decreased 18 +/- 7 percent (mean +/- standard error of the mean) within 5 seconds of occlusion and progressed to systolic outward motion (- 106 +/- 24 percent) at 2 minutes. The time course and type of morphologic changes observed after occlusion were similar to those previously described using invasive methods. Furthermore, such changes preceded electrocardiographic S-T segment elevation. These data suggest that photokymography is a sensitive technique for noninvasive detection of acute ischemic segmental wall motion abnormalities and holds promise as a simple method of detecting ischemic heart disease in man.
Comparative haemodynamic and peripheral vasodilator effects of oral and chewable isosorbide dinitrate in patients with refractory congestive cardiac failure.
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Haemodynamic and electrocardiographic accompaniments of resting postprandial angina.
The early postprandial changes in 10 patients with angiographically proven coronary artery disease and history of postprandial angina were studied by the continuous recording on magnetic tape of the electrocardiogram and haemodynamic variables. The significant changes 20 minutes after a meal not followed by angina included increases in cardiac index and stroke index, with a decrease in systemic vascular resistance. When angina developed after a meal, there were significant increases in mean systemic arterial blood pressure, heart rate, pulmonary capillary wedge pressure, and systemic vascular resistance with decreases in stroke index at the onset of pain rather than at the onset of ischaemic electrocardiographic abnormalities. The first haemodynamic variable to change was pulmonary capillery wedge pressure which tended to increase coincident in time with the electrocardiographic abnormalities. In all cases, postprandial angina occurred within 25 minutes after a meal. In every instance, there was little or no change in the product of heart rate and systolic arterial blood pressure at the onset of the ischaemic electrocardiographic abnormalities at a time when the pulmonary capillary wedge pressure had begun to rise. Postprandial angina, like many cases of rest angina, may rise on the basis of a primary decrease in myocardial perfusion, the nature of which is unclear but merits further investigation.
Mechanism of rest and nocturnal angina: observations during continuous hemodynamic and electrocardiographic monitoring.
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A new technique for assessing right ventricular ejection fraction using rapid multiple-gated equilibrium cardiac blood pool scintigraphy. Description, validation and findings in chronic coronary artery disease.
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Mechanical function of the heart and its alteration during myocardial ischemia and infarction. Specific reference to coronary atherosclerosis.
Altered regional mechanical myocardial performance is an early, sensitive marker of myocardial ischemia, and can be estimated in man with reasonable accuracy. Identification, localization and quantification of abnormalities in mechanical performance can be used to predict the presence of coronary artery disease. Testing techniques that have little or no effect on diagnostic efficiency must be replaced with more sensitive indicators of ischemia. If experimental data are validated by findings in human subjects, accurate identification of regional wall motion changes during test conditions should prove to be a powerful marker of ischemia. To be of value, a diagnostic test must strongly increase the frequency of identification of subjects with a high probabilty for the presence of coronary artery disease in an otherwise low-prevalence population, and of those with known disease who are at the highest risk for complications including myocardial infarction or death.
Complications with flow-directed balloon-tipped catheters.
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Assessment of left ventricular filling by echocardiography in normal subjects and in subjects with coronary artery disease and with asymmetric septal hypertrophy.
To examine the time course of left ventricular filling, a computerized analysis of echocardiograms was performed in 16 normal subjects, 10 patients with coronary artery disease (CAD) but no cardiac enlargement and 7 patients with asymmetric septal hypertrophy (ASH). After hand-controlled digitization of the echocardiogram, a plot of the left ventricular diameter time-curve demonstrated separate phases of rapid filling, slow filling and atrial contribution. The left ventricular diameter at end-systole and at the end of the three diastolic phases was determined by pattern analysis of the diameter-time curve. On analysis of successive beats in the normals, the coefficient of variation for each of these four values of the left ventricular diameter was less than +/- 5%. Between CAD, ASH and normals there was no significant difference in left ventricular end-diastolic diameter, nor in the extent and percentage of diameter shortening during systole. In contrast, abnormalities of the filling pattern were found in CAD and ASH. The maximal rate of diameter lengthening was not different in CAD (13.0 vs 13.7 cm/sec in normals, N.S.) but decreased in ASH (9.3 cm/sec, p less than .01). The percentage of diameter lengthening occurring in the rapid filling phase was decreased in both patient groups (55% in CAD and ASH vs 73% in normals, p less than .001). The slow filling phase did not contribute to more diameter lengthening (13% in CAD and 17% in ASH vs 12% in normals, N.S.). In CAD and ASH, the atrial contribution was markedly increased (33% in CAD and 28% in ASH, vs 15% in normals, p less than .001), and there was a higher rate of diameter lengthening during the atrial contraction (7.6 cm/sec in CAD, p less than .001 and 5.7 cm/sec in ASH, p less than .01, vs 3.1 cm/sec in normals). In conclusion, after computer processing, noninvasive measurements of the left ventricular diameter allows to identify a typical filling pattern in patients with CAD and ASH, consistent with an abnormal compliance of the left ventricle and a compensatory increased atrial contribution.
Scintigraphic and hemodynamic demonstration of transient left ventricular dysfunction immediately after uncomplicated coronary artery bypass grafting.
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[Effect of reduction of impedance in acute myocardial infarct].
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