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Biomedical subjects

T A Ports

Publications and source records attributed to T A Ports.

At least 55 records · Page 3Linked to original sources
PubMed1985

Using beta blockers after MI in the elderly.

Data from the BHAT and the Norwegian timolol trail indicate that beta-blocking agents may provide significant benefit for the post-MI patient--regardless of the location of the infarct or the presence or absence of symptoms (ventricular arrhythmias) or risk factors (heart failure). Despite the lack of data, there is general agreement that beta blockers should be continued for at least 1 to 2 years after infarction in patients who are otherwise asymptomatic, and that these drugs should be continued indefinitely in post-MI patients with angina or hypertension who have no contraindications to beta blockers.

Administration, Oral↗
PubMed1984

Hypertrophic obstructive cardiomyopathy. Effects of acute and chronic verapamil treatment on left ventricular systolic and diastolic function.

Changes in left ventricular systolic and diastolic function and outflow gradient were evaluated in patients with obstructive hypertrophic cardiomyopathy after intravenous acute treatment with verapamil (15 patients) and after six months of oral chronic treatment (11 patients). All patients had severe symptoms despite beta blockade, and the condition of all but two improved appreciably after chronic treatment with verapamil. Resting left ventricular outflow tract gradient decreased in six of 15 patients after intravenous verapamil, and in five of 11 patients after long term treatment, but there was no change in provocable gradients nor any correlation between changes in gradient and improvement in symptoms. Left ventricular ejection rate did not change after intravenous or oral treatment. End systolic pressure/end systolic volume index remained unchanged after oral verapamil treatment. Whereas left ventricular total stroke volume index and end diastolic volume index increased without any significant change in left ventricular end diastolic pressure, indicating improved left ventricular diastolic function. In some patients the left ventricular diastolic pressure-volume curve shifted downwards or to the right or both. These findings suggest that improvement in symptoms with verapamil in patients with obstructive hypertrophic cardiomyopathy is unlikely to be related to changes in left ventricular outflow gradient or in systolic function and may be related to improved diastolic function.

Adolescent↗
PubMed1983

Trimazosin in chronic congestive heart failure: improved left ventricular function at rest and during exercise.

The hemodynamic effects of the oral vasodilator trimazosin were evaluated in patients with chronic congestive heart failure (CHF), initially over a 72-hour period (13 patients), and after 3 months of maintenance therapy (seven patients). During the initial evaluation, cardiac index and stroke work index increased an average of 24% and 37% respectively, and pulmonary capillary wedge pressure decreased by 26%. These beneficial hemodynamic effects were maintained during supine bicycle exercise. After 3 months of maintenance therapy, cardiac index (+30%) and stroke work index (+38%) remained elevated, and pulmonary capillary wedge pressure was lower (-38%). Improved hemodynamics during exercise were also seen after maintenance therapy. Withdrawal of trimazosin was associated with deterioration in hemodynamics and left ventricular function. Thus trimazosin has the potential to cause sustained improvement in left ventricular function, both at rest and during exercise, in patients with chronic CHF.

Adrenergic alpha-Antagonists↗
PubMed1983

Severe aortic insufficiency in juvenile chronic arthritis.

Valvular heart disease is rare in patients with juvenile chronic arthritis. We describe a 27-year-old woman with the systemic-onset form of juvenile chronic arthritis in whom aortic insufficiency necessitated valve replacement. Nodules were seen on both the aortic and anterior mitral leaflets at surgery, and histopathologic evaluation of the excised aortic leaflets demonstrated nonspecific changes similar to those described in rheumatoid valve disease causing aortic insufficiency in adults with rheumatoid arthritis. We believe that this is the first reported case of aortic insufficiency in systemic-onset juvenile chronic arthritis in which the pathologic condition of the valve can be attributed to the underlying disease.

Adult↗
PubMed1983

Mechanism of relief of pacing induced angina with oral verapamil: reduced oxygen demand.

To evaluate the influence of oral verapamil (80 and 120 mg) on angina threshold, coronary blood flow, myocardial oxygen consumption and left ventricular function, we subjected 13 patients with effort angina and fixed obstructive coronary artery disease to atrial pacing at progressively higher heart rates. After 120 mg of verapamil, the time to onset of angina and the heart rate at the onset of ST-segment depression increased by 18% (p less than 0.005) and 10% (p less than 0.001), respectively, without any change in the angina threshold (rate-pressure product at the onset of angina). The rate-pressure product, coronary blood flow and myocardial oxygen consumption were lower at rest and at pre-angina heart rates but not when the angina threshold was reached. Thus, the beneficial effect of verapamil was primarily due to decreased myocardial oxygen demand rather than to increased coronary blood flow. The decreased demand resulted from a lower arterial pressure at each pacing rate. In these patients without heart failure, left ventricular pump function did not deteriorate. This beneficial response was less with 80 mg of oral verapamil. These findings suggest that oral verapamil has a potential role in the management of patients with effort angina due to fixed obstructive coronary artery disease.

Administration, Oral↗
PubMed1982

Efficacy of diltiazem in angina on effort: a multicenter trial.

During a multicenter study 57 patients with exercise-induced angina were evaluated with serial exercise testing to assess the efficacy of diltiazem, a calcium slow channel blocking agent, compared with a placebo. The study consisted of a 1 week single-blind placebo stabilization period followed by a double-blind triple crossover between diltiazem and placebo. Three dose levels were tested (120, 180 and 240 mg/day) in each patient. For the three time-related variables there was a significant dose-related response, with 240 mg/day being the most effective. The increases, over the washout placebo stabilization values, of the time-related variables for the 240 mg/day week compared with the corresponding placebo week were total duration of exercise 1.87 versus 1.05 minutes (p less than 0.002), time to onset of angina 1.81 versus 1.17 minutes (p less than 0.01) and time to appearance of 1 mm S-T segment depression 1.81 versus 1.01 minutes (p less than 0.002). Analysis of exercise variables indicated a significant reduction in heart rate, diastolic blood pressure, and pressure-rate product at submaximal exercise after administration of diltiazem. Diastolic blood pressure was significantly reduced at maximal exercise. Heart rate and pressure-rate product were unchanged at rest during submaximal or maximal exercise. Submaximal and maximal exercise S-T depression was not significantly altered by diltiazem. The reduction in pressure-rate product at submaximal exercise was a possible mechanism for the drug's beneficial effect in enhancing the three time-related variables.

Adult↗
PubMed1982

Minoxidil therapy in chronic congestive heart failure: acute plus long-term hemodynamic and clinical study.

The hemodynamic response to minoxidil, an orally active, potent vasodilator, was evaluated in 11 patients with severe chronic congestive heart failure (CHF). The hemodynamic response was determined following single doses of 10, 15, 20, 25, and 30 mg of minoxidil. The hemodynamic response was characterized by marked increases in cardiac index (+63%) and stroke volume index (+52%) and by decrease in systemic vascular resistance (-38%). There was also a slight decrease in pulmonary capillary wedge pressure from an average of 24 +/- 8 to 21 +/- 7 mm Hg. Although the average mean arterial pressure remained unchanged, one patient developed significant hypotension. Chronic minoxidil therapy (eight patients) was associated with fluid retention and weight gain. In four patients in whom fluid retention could be minimized with larger doses of diuretics, a sustained clinical and hemodynamic improvement was observed. These findings suggest that minoxidil has the potential to improve cardiac function and may be useful in chronic vasodilator therapy of CHF, provided fluid retention can be controlled.

Adult↗
PubMed1982

Constrictive pericarditis: techniques for differential diagnosis.

Although the incidence of constrictive pericarditis is low, the increasing number of patients receiving chronic dialysis, aggressive radiotherapy, or cardiovascular surgery has caused an increase in the iatrogenic incidence. The most common symptoms are dyspnea, fatigue, weight gain, peripheral edema, and abdominal swelling and discomfort. They may be present for years before the diagnosis is made. Physical examination, x-ray studies, electrocardiography, echocardiography, cardiac catheterization, and angiography are all helpful in the differential diagnosis. Pericardiectomy, the only treatment, has a success rate of up to 90%. Untreated, the condition progresses to an incapacitating state.

Angiography↗
PubMed1982

The role of right ventricular systolic dysfunction and elevated intrapericardial pressure in the genesis of low output in experimental right ventricular infarction.

To elucidate the pathophysiology of severe right ventricular infarction (RVI), isolated RVI was produced in 15 dogs with the pericardium intact or open. After RVI in dogs with the pericardium intact, RV systolic pressure decreased by 27%, aortic pressure by 29% and cardiac output by 34%. RV transmural pressure, RV end-diastolic size and intrapericardial pressure increased, left ventricular transmural pressure and end-diastolic size decreased and the diastolic pressures equalized. Pericardiotomy after RVI resulted in increased ventricular transmural pressures and diastolic size, improved cardiac output and resolution of equalized diastolic pressures. RVI in dogs with the pericardium open resulted in similar changes, but of lesser magnitude and without equalization of diastolic pressures. These results indicate that reduced left ventricular preload due to impaired RV systolic function contributes to low cardiac output in RVI. Elevated intra-pericardial pressure further reduced left ventricular preload and produces equal diastolic pressures.

Animals↗
PubMed1982

Hemodynamic benefit of atrial pacing in right ventricular myocardial infarction.

Right ventricular and inferior-posterior myocardial infarctions in four patients were complicated by low-output syndrome unresponsive to increasing intravascular volume. Ventricular pacing was started because of bradyarrhythmias, but failed to increase cardiac output; atrial pacing at identical rates resulted in dramatic increases in cardiac output. The importance of atrial contribution to ventricular function, as well as the role of the pericardium in this clinical setting, are discussed. In treating right ventricular myocardial infarction, atrial or atrioventricular sequential cardiac pacing may be preferable to ventricular pacing.

Aged↗
PubMed1981

Left atrial volume estimation by two-dimensional echocardiography.

We examined 12 patients aged six months to 76 years by echocardiography to determine left atrial volume. The results were compared with angiographic left atrial volumes calculated by the biplane Simpson's rule method. Three two-dimensional planes were used: precordial long axis, apical two-chamber, and four-chamber. Area outlines were traced using a light pen computational system providing single plane area length estimates of left atrial volume. The two apical left atrial outlines were combined, and Simpson's rule method was used to calculate left atrial volume. M-mode echocardiograms performed on these patients were used to estimate left atrial volume. As the results of covariance analysis showed that there was no significant difference in the line of regression in systole and diastole, these data were pooled for subsequent comparison with angiography. The closest correlation with angiography was the biplane Simpson rule method with the echocardiographic left atrial volume (Y) = 1.0, angiographic volume (X) + 6.3 ml, r = 0.86. The single plane area length estimates also correlated well with angiography, but correction factors were required. M-mode estimates of left atrial volume could only correlate to angiography using a power function y = 3.7 X(1.80), r = 0.69. We conclude that left atrial volume can be determined by two-dimensional echocardiography and that this technique is superior to M-mode echocardiography.

Adolescent↗
PubMed1981

Dobutamine in chronic ischemic heart failure: alterations in left ventricular function and coronary hemodynamics.

Changes in cardiac performance and coronary hemodynamics were evaluated during dobutamine infusion in patients with chronic heart failure associated with ischemic heart disease. At the maximal administered dose (10 micrograms/kg per min) cardiac index increased by 54 percent and stroke work index by 65 percent, indicating improved left ventricular function. Coronary sinus flow and myocardial oxygen consumption increased concomitantly, but myocardial lactate production occurred in only one of eight patients. These findings suggest that improved left ventricular function with dobutamine is associated with increased myocardial oxygen consumption; however, overt myocardial ischemia occurs infrequently.

Aged↗
PubMed1981

Influence of oral prazosin therapy on exercise hemodynamics in patients with severe chronic heart failure.

In 10 patients with severe chronic congestive heart failure, changes in hemodynamic and cardiac performance at rest and during exercise were evaluated following short-term oral prazosin therapy. The median total dose of prazosin was 43 mg (range 23 to 95 mg) and the median duration of therapy was 47 hours (range 18 to 92 hours). 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). The magnitude of the increase in pulmonary capillary wedge pressure during exercise with the addition of prazosin was also significantly less than that during conventional therapy, suggesting improved cardiac performance during exercise. Peak oxygen consumption, peak lactate concentration and rate of disappearance of the increased concentration of lactate induced by exercise, however, remained unchanged following prazosin therapy. These findings suggest that short-term prazosin therapy, as other vasodilators, improves cardiac performance during exercise but may not necessarily influence oxygen consumption.

Administration, Oral↗
PubMed1981

Halothane and morphine-nitrous oxide anesthesia in patients undergoing coronary artery bypass operation. Patterns of intraoperative ischemia.

To examine whether the hemodynamic responses to halothane or morphine-nitrous oxide anesthesia produce different patterns of myocardial ischemia in patients undergoing myocardial revascularization, we studied 26 patients anesthetized with nitrous oxide (50%) and either halothane (0.2% to 1.0% end-tidal concentration) or morphine (2 mg/kg, given intravenously). We measured systemic and coronary hemodynamics and took blood samples to measure blood gases, oxygen content, and lactate and norepinephrine concentrations. Systemic blood pressure, rate-pressure produce, systemic vascular resistance, cardiac output, and stroke work were elevated following sternotomy in patients anesthetized with morphine, whereas halothane obtunded these hemodynamic responses to surgical stress. Intraoperative myocardial ischemia occurred in both patient groups. Ten of 14 patients receiving halothane and eight of 12 receiving morphine had at least one episode of either ST-segment depression or myocardial lactate production. The difference between these groups was not statistically significant. Only patients anesthetized with morphine had a significantly elevated rate-pressure product when ischemia occurred. In this selected series of patients subjected to myocardial revascularization, two sustained a myocardial infarction and four died in the postoperative period. The incidence of these and other indices of postoperative morbidity was not related to choice of primary anesthetic and did not differ between the patients who sustained ischemia and those who did not.

Anesthesia, General↗