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Biomedical subjects

K Chatterjee

Publications and source records attributed to K Chatterjee.

At least 235 records · Page 13Linked to original sources
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

Thallium-201 myocardial perfusion scintigraphy to evaluate patients after coronary bypass surgery.

To determine the utility of thallium-201 stress scintigraphy in assessing the results of coronary bypass surgery, chest pain, stress electrocardiograms and scintigrams were evaluated in 27 patients postoperatively. These findings were compared with coronary angiographic data in which a significant postoperative lesion was defined as 75 percent or more stenosis in a graft, its distal vessel or in an ungrafted native vessel. As an indicator of postoperative coronary lesions, chest pain lacked sensitivity (60 percent) and was nonspecific (20 percent). The stress electrocardiogram had poor sensitivity (60 percent) and good specificity (86 percent) but was not helpful in six patients who had equivocal or suboptimal tests. The scintigram had good sensitivity (77 percent) and was highly specific for the diagnosis of coronary stenosis. It was significantly more specific than chest pain (P less than 0.01), gave excellent localizing information and added to the accuracy of both conclusive and inconclusive stress tests. In nine patients with preoperative stress scintigrams, comparison of pre- and postoperative studies reflected the éffects of bypass surgery on coronary perfusion. Scintigraphy is a useful technique for the noninvasive evaluation of the patient after coronary bypass surgery, and postoperative scintigraphy alone is of great value in documenting surgical results.

Adult↗
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

Studies on L-ascorbic acid metabolism in rats under chronic toxicity due to organophosphorus insecticides: effects of supplementation of L-ascorbic acid in high doses.

The effects of chronic administration of two organophosphorus insecticides, parathion and malathion on the growth rate, ascorbic acid metabolism and some other nutritional and physiological parameters in rats were studied. Both parathion and malathion toxicity retarded the growth rate of rats. Inhibition of brain acetylcholinesterase was taken as an index of organophosphorus insecticide toxicity. Haemoglobin concentration of blood and organ weights were not affected under the toxic conditions. Parathion and malathion administration stimulated the activity of L-gulonolactone oxidase along with a simultaneous increase in the tissue storage and urinary excretion of vitamin C. The activities of other enzymes of ascorbic acid metabolism, dehydroascorbatase, uronolactonase, and L-gulonate dehydrogenase and decarboxylase were altered under the experimental conditions. Only minor histological changes of the liver and kidney tissues were noted under parathion and malathion toxicities. Excess intake of vitamin C under the toxic conditions was found to be very effective in counteracting the growth retardation and also the alterations produced by parathion and malathion both at the enzymatic and histological levels.

Animals↗
PubMed1978

Pronounced dependence of ventricular endocardial QRS potentials on ventricular volume.

To evalulate the relation between ventricular endocardial potentials (QRS amplitude) and ventricular dimensions, left and right ventricular endocardial potentials were recorded with hook electrodes in anaesthetised open-chest dogs during transfusion and withdrawal of blood. Left ventricular end-diastolic diameter was measured by ultrasonic crystals, and end-diastolic volume was determined by thermodilution. In each dog, left ventricular endocardial potentials, whether recorded from anterior or posterolateral walls, decreased linearly as left ventricular end-diastolic diameter or volume increased, and vice versa. With an average increase in left ventricular end-diastolic diameter from 40.1 +/- 1.7 to 44.6 +/- 1.8 mm, left ventricular endocardial potentials decreased from 32.8 +/- 2.5 to 23.5 +/- 2.3 mV (P less than 0.001); and for an increase in left ventricular end-diastolic volume from 1.36 "/- 1.25 to 3.43 +/- 0.58 ml/kg left ventricular endocardial potentials decreased from 36.2 +/- 6.6 to 14.9 +/- 4.3 mV (P less than 0.001). Changes in right ventricular endocardial potentials paralleled the changes in left ventricular endocardial potentials. These findings indicate that acute changes in ventricular dimensions influence endocardial potentials considerably, and suggest a potential clinical application for detecting acute changes in ventricular volume.

Action Potentials↗
PubMed1978

Segment stroke work and metabolism depend on coronary blood flow in the pig.

We determined the mechanical and metabolic effects of graded myocardial ischemia in 23 open-chest, anesthetized pigs. By connecting the midportion of the left anterior descending artery (LAD) to the carotid artery via a constant volume, calibrated pump, we reduced the flow in the LAD to 0, 25, 50, and 75% of control rates for periods of 1 h. Flows of 100% and 150% were also examined. Using pairs of ultrasonic crystals to measure segment dimensions, we calculated segment shortening and thickening, and total and systolic stroke work in the ischemic and normally perfused segments. Blood gases, pH, and lactate and inosine balances were determined from the regional coronary venous blood. At coronary blood flows of 0, 25, 50, and 75% of normal resting flow, total segment work was 8 +/- 8, 25 +/- 4, 51 +/- 5, and 80 +/- 6% of control, respectively, while systolic segment work was -2 +/- 5, -10 +/- 5, 40 +/- 5, and 86 +/- 7% of control, respectively (means +/- SE). Thus, the decrease in total segment stroke work is proportional to the decrease in flow over the range 0-100%. However, no useful work (i.e., systolic work) is done until flow exceeds 25%. Segment shortening and thickening are significantly depressed with flows diminished by only 25%. Segmental inosine production correlates with lactate production and parallels decreased mechanical performance.

Animals↗
PubMed1978

The clinical estimation of acute myocardial infarct size with 99mTechnetium pyrophosphate scintigraphy.

We evaluated scintigraphic techniques in estimating infarct size. In 26 patients with acute transmural myocardial infarction, 99mTechnetium pyrophosphate (TcPYP) infarct scintigraphy, gated cardiac blood pool scintigraphy and 201-Thallium (201-Tl) perfusion scintigraphy were performed. Invasive hemodynamic measurements were obtained and serial venous blood specimens taken for measurement of total and MB creatine phosphokinase (CPK). In farct size was estimated from the area of abnormal TcPYP uptake, the extent of reduced 201-Tl uptake, the percentage of abnormally contracting segments, and serial enzyme measurements. Left ventricular ejection fraction (LVEF) and stroke work index (LVSWI) were calculated. TcPYP infarct area was associated with the extent of reduced 201-Tl uptake (r = 0.66), the percentage of abnormally contracting segments (r = 0.64), and with both LVSWI (r = 0.73) and LVEF (r = 0.58). TcPYP infarct area did not correlate with cumulative total or MB-CPK release or the integrated total CPK-time curve, nor did the enzyme estimates of infarct size correlate with LVSWI or LVEF. Variable perfusion of infarcts of different sizes may explain the lack of correlation between TcPYP infarct area and enzyme estimates of infarct size. A combination of anatomic and functional indices derived from scintigraphic and hemodynamic measurements may provide the best assessment of infarct size.

Acute Disease↗
PubMed1978

The noninvasive diagnosis of right ventricular infarction.

We evaluated scintigraphy and echocardiography for the diagnosis of right ventricular (RV) infarction. Of 26 patients with acute transmural myocardial infarction (MI), six with inferior MI had abnormal radionuclide uptake localized to the RV free wall on infarct scintigraphy or segmental akinesis of the RV free wall on gated radioangiography or both. These six patients with RV involvement (group I) were compared with the remaining nine with inferior MI (group II) and 11 with anterior MI (group III). RV/LV area ratios determined radioangiographically were significantly greater in group I than group II in diastole and systole. Echocardiographic RV enddiastolic dimension and RV/LV end-diastolic dimension ratio were significantly greater and RV stroke work index was significantly lower in group I than in group II. Predominant RV involvement in inferior MI may occur commonly. Anatomic and functional evidence of this diagnosis can be obtained noninvasively.

Echocardiography↗
PubMed1978

Coronary sinus reflux. A source of error in the measurement of thermodilution coronary sinus flow.

In seven patients thermodilution coronary sinus flow (TD-CSF) was higher (164 +/- 21 ml/min) during ventricular pacing than during atrial pacing (119 +/- 21 ml/min, P less than 0.005) at identical heart rate, without an increase in the determinants of myocardial oxygen consumption. To assess the possibility of right atrial admixture in coronary sinus blood during ventricular pacing we compared electromagnetic coronary arterial blood flow (CBF) with TD-CSF in nine dogs during interventions that increased right atrial pressure. During ventricular pacing, rapid atrial pacing, pulmonary artery constriction and increased intrathoracic pressure, right atrial pressure increased and electromagnetic CBF was significantly less (41-166%) than TD-CSF. Marked reflux from the right atrium to the coronary sinus was also demonstrated by bolus injection of cold saline into the right atrium and continuous infusion of contrast material into coronary sinus. Caution needs to be exercised in interpreting TD-CSF in the presence of changing right atrial pressure.

Adult↗
PubMed1978

Beneficial effects of hydralazine in severe mitral regurgitation.

The severity of mitral regurgitation is, in part, determined by aortic impedance to left ventricular outflow. Sodium nitroprusside acutely decreases regurgitant flow, but the importance of its dual vasodilating effects, the lowering of peripheral vascular resistance and increasing of venous capacitance, is unclear. We studied the hemodynamic response to intravenous hydralazine, which selectively acts on the arteriolar resistance bed, in 10 patients with severe mitral regurgitation. Hydralazine produced a 50% increase in forward stroke volume (22 +/- 2 to 33 +/- 3 ml/m2, P less than 0.001) and a 33% reduction in regurgitant stroke volume (40 +/- 6 to 27 +/- 6 ml/m2, P less than 0.001), with a resultant fall in pulmonary capillary wedge v wave and mean pressures. Unlike nitroprusside, it did not alter left ventricular end-diastolic volume or pressure. Oral hydralazine maintained this hemodynamic improvement for at least 48 hours and, in three patients, provided more sustained clinical improvement. We conclude that hydralazine, by virtue of its selective lowering of aortic impedance, reduces the amount of mitral regurgitation and thus may be a useful mode of interim or chronic therapy in selected patients.

Adult↗
PubMed1978

The specificity of pyrophosphate myocardial scintigrams in patients with prior myocardial infarction: concise communication.

Fifty-five patients with old (9 days to 10 yr) transmural infarcts but with no evidence of recent infarction, were imaged with Tc-99m pyrophosphate. Discrete uptake was rare in the setting of an old infarct. Diffuse uptake was neither sensitive to, nor specific for, acute infarction. Prior infarction will rarely cause diagnostic error if the discrete pattern is required for a positive diagnosis.

Acute Disease↗
PubMed1978

Biochemical studies on polychlorinated biphenyl toxicity in rats: manipulation by vitamin C.

The effects of chronic polychlorinated biphenyl (PCB) compound toxicity on L-ascorbic acid metabolism in rats have been studied. PCB treatment brought about a depression in the activities of the enzymes L-gluonolactone oxidase and dehydroascorbatase along with an increased tissue levels and urinary excretion of L-ascorbic acid. PCB toxicity drastically disturbed the normal histological pattern of the liver cells and also significantly changed the hepatic lipid composition. L-ascorbic acid supplementation to the toxicated group of animals, although could not prevent the growth retardative effect of PCB, could afford a definite protection against the enzyme activity alterations and histological changes as caused by PCB toxicity.

Alcohol Oxidoreductases↗
PubMed1977

Selective cannulation of the anterior interventricular vein and coronary sinus: potential applications.

A technique of cannulation of the anterior interventricular vein (AIV) selectively, along with selective cannulation of the coronary sinus, is described. The technique was successful in 61 of 82 patients (76%) in whom it was attempted. There were no serious complications. The technique allows one to obtain blood samples simultaneously from the anterior interventricular vein and the coronary sinus, so that the metabolism of the left ventricular anterior wall and that of the overall left ventricle can be studied. Possible clinical applications of simultaneous investigation of the left ventricular anterior wall and global myocardial metabolism are discussed.

Cardiac Catheterization↗
PubMed1977

Hemodynamic advantage of combined administration of hydralazine orally and nitrates nonparenterally in the vasodilator therapy of chronic heart failure.

Patients with severe left ventricular failure generally have both reduced cardiac output and increased pulmonary and systemic venous pressures. A study was therefore made of the use of combined vasodilator therapy with nonparenterally administered nitrates, which act primarily on venous capacitance vessels and thus reduce preload, and orally administered hydralazine, which acts on arteriolar resistance vessels and thus reduces afterload. Twelve patients with chronic refractory heart failure were given these drugs individually and in combination during continuous hemodynamic monitoring. Heart rate and arterial pressure did not change significantly. Nitrates significantly reduced filling pressures of both ventricles without affecting cardiac index. Hydralazine did not alter filling pressures but dramatically increased cardiac index. The hemodynamic effects of each drug were additive during combined therapy, resulting in a 36 percent (28 to 18 mm Hg) mean decrease in left ventricular filling pressure and a 58 percent (2.1 to 3.3 liters/min per m(2)) mean increase in cardiac index. The seven patients who have continued to receive combined therapy for 3 to 10 months have shown sustained clinical improvement.

Administration, Oral↗
PubMed1977

Vasodilator treatment for acute and chronic heart failure.

The current status of the use of vasodilator drugs in the treatment of acute and chronic heart failure has been reviewed. It is apparent that vasodilator treatment can be used effectively in some patients with heart failure with a beneficial haemodynamics response, and that vasodilator agents are likely to find an important place in the management of such patients. Vasodilator treatment may be associated with complications and must be used with care. Though several nonparenteral vasodilator agents have been investigated, no ideal drug is yet available for the treatment of chronic heart failure. Nevertheless, it is probable that suitable drugs will emerge and find an important place in the management of such patients.

Aortic Valve Insufficiency↗