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Biomedical subjects

T A Ports

Publications and source records attributed to T A Ports.

At least 73 records · Page 4Linked to original sources
PubMed1980

Oral hydralazine in chronic heart failure: sustained beneficial hemodynamic effects.

Hemodynamic effects of oral hydralazine (200 to 400 mg/d) were evaluated in 11 patients with chronic heart failure after short-term (24 hours) and long-term (average, 8.3 months) therapy. In seven of 11 patients, hemodynamic changes were evaluated after withdrawal of hydralazine. During early study, cardiac index, stroke volume index, and stroke work index increased by an average of 56%, 59%, and 68%, respectively, and systemic vascular resistance decreased by 39%. During late study, cardiac index (+65%), stroke volume index (+88%), and stroke work index (+98%) remained higher and systemic vascular resistance (-41%) lower than control values. Withdrawal of hydralazine caused a decrease in cardiac index, stroke volume index, and stroke work index and an increase in systemic vascular resistance. Heart rate and arterial, pulmonary capillary wedge, and right atrial pressures did not change significantly. These findings suggest that oral hydralazine produces sustained beneficial hemodynamic effects in patients with chronic heart failure.

Administration, Oral↗
PubMed1980

Changes in mixed venous and coronary sinus P50 secondary to anesthesia and cardiac disease.

Changes in oxyhemoglobin dissociation compensate partially for decreased O2 transport caused by high altitude, anemia, and cardiac disease. This investigation determined whether similar changes occurred in patients undergoing myocardial revascularization and the possible significance of such changes. In 15 patients scheduled for coronary vein bypass surgery the following were inserted: a #7 French catheter into the coronary sinus or great cardiac vein, a pulmonary arterial catheter (Swan-Ganz), and a radial arterial catheter. Patients were anesthetized with either halothane-N2O 50% or morphine (2 mg/kg IV) with N2O 50%. Hemodynamic status was measured and blood samples were taken from the catheters in the preoperative period and after endotracheal intubation, sternotomy, bypass, and chest closure. Blood samples were analyzed for pH, blood gas tensions, and O2 saturation. Values for P50 for mixed venous and coronary sinus blood were calculated from O2 tension and saturation. Patients were divided into two groups on the basis of peroperative mixed venous P50 values: group I had normal P50 levels of 26.1 +/- 2.0 torr (mean +/- SD); group II had elevated values for mixed venous blood P50 of 32.5 +/- 1.6 (mean +/- SD). Unlike group I, group II had depressed ventricular function and higher P50 values for coronary sinus blood than for mixed venous blood. Induction of anesthesia increased P50 values in group I but not in group II and removed the significant differences between group I and group II mixed venous P50 values. In group II patients, cardiopulmonary bypass lowered the elevated P50 of coronary sinus blood so that it equaled P50 for mixed venous blood. It is concluded that induction of anesthesia may elevate P50 in patients who have normal preoperative P50 values. The already elevated P50 values of patients with ventricular dysfunction did not change. Cardiopulmonary bypass decreased coronary sinus P50 in group II patients, and this change might be deleterious if the original elevation represents a compensatory response to a reduction in O2 transport.

Anesthesia↗
PubMed1979

Paradox of improved exercise but not resting hemodynamics with short-term prazosin in chronic heart failure.

In patients with chronic heart failure exercise allows the simultaneous observation of the cardiovascular pathophysiology and the symptoms of these patients. We administered short-term, oral prazosin to 10 patients with severe chronic heart failure. Prazosin increased cardiac output and stroke volume significantly during exercise (both P less than 0.05) but not at rest (both P greater than 0.10). Prazosin decreased the arteriovenous oxygen difference and left ventricular filling pressure significantly during exercise (both P less than 0.05) but not at rest (both P greater than 0.10). There was no significant correlation between prazosin-induced changes at rest and during exercise in cardiac output (r = 0.12), stroke volume (r = 0.02), arteriovenous oxygen difference (r = 0.33) or left ventricular filling pressure (r = 0.43). Prazosin predominantly affects hemodynamics during exercise because its pharmacologic activity as an alpha-adrenergic blocking agent is most prominent during exercise. The full evaluation of prazosin-induced changes in the hemodynamics of patients of patients with chronic heart failure requires evaluation during exercise.

Aged↗
PubMed1979

Detection of left ventricular functional reserve by supine exercise hemodynamics in patients with severe, chronic heart failure.

Hemodynamic changes during exercise were evaluated in 20 patients with severe, chronic congestive heart failure. Two groups were identified by their stroke work response to maximal exercise. Group I (eight patients) showed an increase in stroke work index. This occurred because the stroke volume increased and the difference between mean systolic pressure and left ventricular filling pressure increased. Group II (12 patients) showed a decrease in stroke work index. This occurred because stroke volume decreased while the difference between mean systolic pressure and left ventricular filling pressure did not change. Despite hemodynamic differences, the groups could not be distinguished by the usual clinical criteria for heart failure including etiology, New York Heart Association functional class, heart size on chest X-ray film or duration of heart failure. Clinical criteria are relatively insensitive in predicting the exercise hemodynamics of any given patient with chronic severe heart failure. Determining the exercise hemodynamics may be helpful as a means of assessing left ventricular functional reserve in heart failure. Prognostic implications, drug therapy and prescription of activities may require adjustment based on this spectrum of hemodynamic response to exercise in patients with chronic heart failure.

Adult↗
PubMed1979

Influence of short-term oral hydralazine therapy on exercise hemodynamics in patients with severe chronic heart failure.

Changes in left ventricular performance were evaluated in 14 patients with functional New York Heart Association class III or IV chronic heart failure before and after the addition of oral hydralazine to conventional therapy. With conventional therapy, cardiac output increased from 3.4 +/- 0.8 (mean +/- 1 standard deviation) at rest to 4.7 +/- 1.4 liters/min during exercise. This increase in cardiac output on exercise during conventional therapy was mainly due to an increase in heart rate. After the addition of hydralazine, cardiac output at rest increased to 5.0 +/- 1.4 liters/min. The increase in cardiac output was essentially due to an increase in stroke volume. This enhanced stroke volume after hydralazine therapy was maintained during exercise. Hydralazine therapy did not change either the left ventricular filling pressure at rest or the magnitude of increase in left ventricular filling pressure during exercise. Nevertheless, increased cardiac output and stroke volume with similar changes in left ventricular filling pressure during exercise indicated improved left ventricular performance after hydralazine therapy. After short-term hydralazine therapy, symptom-limited peak exercise work load, duration of exercise and maximal oxygen consumption during exercise did not increase. Clinical follow-up at 2 months after long-term therapy revealed subjective improvement in exercise tolerance in 13 of the 14 patients.

Administration, Oral↗
PubMed1979

Operative correction of total left anomalous pulmonary venous return.

The evaluation, surgical repair, and follow-up are described in an asymptomatic 27-year-old man with unilateral total anomalous pulmonary venous return from the left lung through an innominate vein and a patent foramen ovale. The anomalous vein was divided and anastomosed directly to the left atrium using a vascular technique that produced an orifice larger than the vein diameter. Radionuclide scanning accurately identified the anomaly before operation and allows periodic noninvasive reevaluation after operation. Correction is recommended in all patients with unilateral anomalous pulmonary venous return because disease in the one normal lung could be fatal.

Adult↗
PubMed1979

Comparison of haemodynamic effects of oral hydralazine and prazosin hydrochloride in patients with chronic congestive heart failure.

The comparative haemodynamic effects of oral prazosin hydrochloride and hydralazine were evaluated in 11 patients with chronic congestive heart failure. The maximum total dose of prazosin received by an individual varied up to 25 mg. Ten patients received a maximum of 75 mg and one received 50 mg of hydralazine at six-hour intervals. There was no significant change in heart rate with either drug. Decrease in mean arterial and left ventricular filling pressures were modest and similar with both agents. With prazosin, the average cardiac index increased 20 per cent and systemic vascular resistance decreased 20 per cent. By contrast, hydralazine increased cardiac index by 58 per cent and decreased systemic vascular resistance by 40 per cent. The increase in stroke work and stroke volume indices was significantly greater with hydralazine than with prazosin. These findings suggest that in some patients with severe chronic congestive heart failure, improvement in left ventricular performance may be greater with hydralazine than with prazosin.

Adult↗
PubMed1979

Echocardiographic evaluation of ventricular septal aneurysms.

The spontaneous closure of ventricular septal defects is frequently associated with septal aneurysm formation. In this paper we discuss the M-mode and two-dimensional echocardiographic findings in nine children with aneurysms of the ventricular septum in association with ventricular septal defects. In all patients the diagnosis was confirmed by angiography. The ventricular septal aneurysms were detected by both M-mode and two-dimensional echocardiography. With M-mode echocardiography, septal aneurysms could be recognized by a pattern of multiple systolic echoes within the right ventricle. With two-dimensional echocardiography, the protrusion of the septal aneurysm into the right ventricle could be seen from several views and the location and the relative size of the aneurysm assessed. Echocardiographic techniques useful in the detection of ventricular septal aneurysms are discussed and examples presented.

Adolescent↗
PubMed1979

Left ventricular volume from paired biplane two-dimensional echocardiography.

To evaluate the applicability of two-dimensional echocardiography to left ventricular volume determination, 30 consecutive patients undergoing biplane left ventricular cineangiography were studied with a wide-angle (84 degrees), phased-array, two-dimensional echocardiographic system. Two echographic projections were used to obtain paired, biplane, tomographic images of the left ventricle. We used the short-axis view (from the precordial window) as an anolog of the left anterior oblique angiogram, and the long-axis, two-chamber view (from the apex impulse window) as a right anterior oblique angiographic equivalent. A modified Simpson's rule formula was used to calculate systolic and diastolic left ventricular volumes from the biplane echogram and the biplane angiogram. These methods correlated well for ejection fraction (r = 0.87) and systolic volume (r = 0.90), but only modestly for diastolic volume (r = 0.80). These correlations are noteworthy because 65% of the patients had significant segmental wall motion abnormalities. The volumes determined from the minor-axis dimensions of M-mode echograms in 23 of the same patients correlated poorly with angiography.

Adult↗
PubMed1979

Attenuation of prazosin effect on cardiac output in chronic heart failure.

The persistence of the hemodynamic effects of prazosin was studied in 12 patients with chronic congestive heart failure. Multidose evaluation involving five 5-mg doses showed the initial decrease in systemic vascular resistance and increase in cardiac index, stroke work index, and stroke volume index to be transient. Doubling the dose did not restore effect. Modest decreases in pulmonary capillary-wedge and mean arterial pressures persisted throughout the study. In six patients, plasma prazosin concentration measured at times of hemodynamic observations showed the initial hemodynamic effect of prazosin to attenuate upon further administration despite mean plasma concentrations that exceeded those measured after the first dose. In patients with chronic heart failure, resting hemodynamic studies suggest a rapid attenuation of prazosin-mediated hemodynamic effect in the presence of adequate plasma concentration. Recognizing this phenomenon, if long-term prazosin therapy for congestive heart failure is contemplated, we suggest the hemodynamic response in individual patients be monitored.

Adult↗
PubMed1979

Early and long-term prognosis after vasodilator therapy in the acute phase of myocardial infarction.

Cautious administration of vasocilator agents with careful hemodynamic monitoring may improve cardiac function in many patients with severe pump failure and cardiogenic shock complicating myocardial infarction. However, the immediate prognosis tends to improve only in a specific subset of patients, that is, those with left ventricular stroke work index above 10 g.m/m2 and elevated left ventricular filling pressure. In the presence of very severe pump failure, cardiogenic shock, stroke work index of less than 10 g.m/m2 and grossly elevated left ventricular filling pressure, vasodilator therapy alone does not tend to improve in-hospital mortality. Furthermore, the long-term prognosis in the survivors with severe pump failure complicating myocardial infarction remains unfavorable. The poor prognosis of these patients is probably a result of the extensive myocardial necrosis sustained at the onset of infarction.

Drug Evaluation↗
PubMed1978

Long-term outpatient vasodilator therapy of congestive heart failure. Consideration of agents at rest and during exercise.

Increased left ventricular filling pressure and reduced cardiac output are two major hemodynamic deficits in pump failure. In patients with chronic heart failure, consequences of these hemodynamic deficits and diminished cardiac reserve are manifested initially during stress and eventually at rest. The purpose of therapeutic interventions include reduction of ventricular filling pressure increase in cardiac output and improvement in cardiac reserve. To achieve these goals, the hemodynamic effects of predominantly venodilators (nitrates), predominantly arteriolar dilators (hydralazine) and the combination of nitrates and hydralazine were evaluated in patients with chronic heart failure at rest: left ventricular filling pressure (mm Hg) control 28, nitrates 17, hydralazine 25, nitrates plus hydralazine 18; cardiac output (liters/min/m2) control 2.1, nitrates 2.1, hydralazine 3.2, nitrates plus hydralazine 3.3; mean blood pressure (mm Hg) control 87, nitrates 85, hydralazine 83, nitrates plus hydralazine 85. These data suggest improved left ventricular performance with a combination of nitrates and hydralazine. Exercise hemodynamics improved in some patients, suggesting that such vasodilator therapy may be beneficial in chronic heart failure.

Chronic Disease↗
PubMed1978

Two-dimensional echocardiographic assessment of Ebstein's anomaly.

Nine patients with Ebstein's anomaly of the tricuspid valve were studied by two-dimensional echocardiography, using the standard long and short axis views as well as the apex four chamber view. With this latter view, the displacement of the tricuspid valve into the right ventricle was clearly seen in all nine cases of Ebstein's anomaly and was not noted in a control population. The severity of the tricuspid displacement was assessed by comparing the position of the mitral and tricuspid valves relative to the cardiac apex. The apex four chamber view allowed visualization of the atrioventricular (AV) ring simultaneously with the displaced tricuspid valve, and therefore the size of the "atrialized" right ventricle, true right ventricle and right atrium could be determined. These dimensions compared favorably with angiography.

Adolescent↗