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Biomedical subjects

U Thadani

Publications and source records attributed to U Thadani.

At least 91 records · Page 5Linked to original sources
PubMed1981

Kinetics of isosorbide dinitrate and relationships to pharmacological effects.

1 The inter-relationships among oral isosorbide dinitrate (ISDN) dose, drug pharmacokinetics and pharmacological effects were studied in 12 angina patients following single and chronic doses of 15, 30, 60 and 120 mg. 2 Significant accumulation of intact ISDN in plasma was observed after four times a day dosing at 30, 60 and 120 mg for 1 week. 3 The area under the plasma concentration v time curve (AUC), form 0-6 h, was shown to be proportional to dose following single doses. In contrast, AUC increased disproportionately to dose after chronic dosing. 4 Pharmacokinetic correction provided modest improvements in the dose-response relationships of ISDN. 5 Adverse hypotensive effects were observed in five patients after the single 60 mg dose. These patients showed statistically higher AUC and lower intrinsic clearance of ISDN at doses of 15, 30 and 60 mg compared to those who did not develop adverse effects. A possible relationship exists, therefore, between lower drug clearance and hypersensitivity to ISDN.

Adult↗
PubMed1980

Subaortic annular left ventricular aneurysm: an unusual cause of aortic regurgitation.

A subaortic left ventricular aneurysm in a 21-year-old white woman is described. The clinical features were those of moderately severe aortic regurgitation, and the chest x-ray film showed cardiac enlargement with a bulge on the left heart border. Angiography confirmed the presence of gross aortic regurgitation and revealed an aneurysm behind the aortic root. At surgery, the aneurysm was found to be located below the aortic valve ring and communicated with the left ventricle through an ostium of 2.5 cm. Aortic valve replacement and closure of the aneurysmal ostium were carried out successfully.

Adult↗
PubMed1980

Comparison of five beta-adrenoreceptor antagonists with different ancillary properties during sustained twice daily therapy in angina pectoris.

The effects of five beta-adrenoreceptor blocking agents and placebo during twice daily sustained therapy were compared in 23 patients with stable, exertional angina pectoris. The study was double blind in design, and each drug was prescribed for a period of one month in a random fashion. The number of anginal attacks and consumption of glyceryl trinitrate tablets during the one month period were significantly reduced by a similar degree during therapy with all five beta blocking drugs in comparison to the placebo (P less than 0.01). Exercise tolerance, when assessed 12 hours after a previous dose had been given and 1 hour after the morning dose was given, also improved by a similar degree with all five drugs in comparison to the placebo (P less than 0.01). The increase in exercise duration was associated with a significant reduction in the S-T segment depression, heart rate, systolic blood pressure, and the product of heart rate and systolic blood pressure, with each of the five drugs--effects markedly different from those obtained with the placebo (P less than 0.01). These data show that noncardioselective (propranolol and oxprenolol) and cardioselective (practolol, metoprolol and tolamolol) agents, as well as drugs with intrinsic sympathomimetic activity (oxprenolol and practolol), were equally effective antianginal agents during sustained therapy. Furthermore, twice daily therapy with any of these drugs was effective in the management of patients with angina pectoris.

Adrenergic beta-Antagonists↗
PubMed1979

Comparison of the immediate effects of five beta-adrenoreceptor-blocking drugs with different ancillary properties in angina pectoris.

We compared the immediate effects of five beta-adrenoreceptor-blocking agents in 16 patients with stable angina pectoris. Acute dose-response studies showed that all five drugs improved exercise tolerance and reduced ST-segment depression, heart rate and blood pressure by a similar degree in comparison with a placebo (P less than 0.01). Near maximum improvement in exercise tolerance occurred when the acute cumulative oral dose had reached 160 mg for propranolol and oxprenolol, 200 mg for metoprolol and tolamolol and 400 mg for practolol. When these drugs were administered as a single doses, increase in walking time before the development of angina and reduction in ST-segment depression, heart rate and systolic blood pressure all occurred within one hour and persisted for eight hours--effects markedly different from the response to a placebo (P less than 0.01). These data show that non-cardioselective agents (propranolol and oxprenolol), cardioselective agents (practolol, metoprolol and tolamolol), as well as drugs with intrinsic sympathomimetic activity (oxprenolol and practolol), were equally effective in the treatment of angina pectoris.

Adult↗
PubMed1979

Propranolol in angina pectoris: duration of improved exercise tolerance and circulatory effects after acute oral administration.

The duration of the effects of single oral doses of 80 and 160 mg of propranolol was studied in 11 patients with stable, exercise-induced angina pectoris. After administration of both doses, plasma propranolol levels peaked at 2 hours in 8 of the 11 patients and thereafter declined exponentially with an average plasma half-life of 3.98 hours (range 1.4 to 4.3) after the 80 mg dose and 4.28 hours (range 1.9 to 5.4) after the 160 mg dose. There was wide interindividual variation in plasma propranolol concentration at any given time after each dose. Treadmill walking time to the onset of angina, the total duration of exercise and the total external work performed were significantly greater by 1 hour after each dose of propranolol than after placebo. This improvement in exercise tolerance persisted unchanged for 8 hours (P less than 0.001) and was still significant although less marked at 12 hours (P less than 0.05). Improvement in exercise tolerance after propranolol was associated with a significant reduction in S-T segment depression during exercise. Both at rest and during exercise, heart rate, systolic blood pressure and rate-pressure product decreased after propranolol, and these circulatory effects persisted for 12 hours. Changes in walking time, heart rate and systolic blood pressure were similar after 80 and 160 mg of propranolol. Despite the increase in exercise duration and in total work performed after propranolol, the rate-pressure product at the onset of angina was lower after propranolol. In view of the prolonged effects of single oral doses of 80 and 160 mg of propranolol, it is suggested that administration of propranolol twice daily should be adequate in treating patients with stable angina pectoris. These studies also demonstrate that routine measurement of plasma propranolol levels is of little practical value in the management of patients with angina pectoris.

Administration, Oral↗
PubMed1979

Effects of glucose-insulin-potassium infusion on the angina response during treadmill exercise.

The effects of glucose-insulin-potassium (GIK) and placebo normal saline (S) infusion on treadmill-walking time to angina, ST depression, heart rate (HR), systolic blood pressure (SBP), rate pressure product (RPP), blood glucose (G), lactate (L) and free fatty acids (FFA) were studied in 14 non diabetic patients with exertional angina. For the whole group, the post-GIK walking time to angina (393 +/- 33 sec, mean +/- SEM) was greater than the values during control GIK (319 +/- 20 sec, p less than 0.02) and post-S infusion (334 +/- sec, p less than 0.05), but circulatory and ST responses were similar in post-GIK and post-S studies. 7 of the 14 patients experienced significantly greater improvement in exercise tolerance following GIK (467 +/- 39 sec) in comparison to control GIK (313 +/- 29 sec, p less than 0.001) and post-S infusion (334 +/- 32 sec, p less than 0.005) and exercised to a higher HR, SBP and RPP after GIK than after S infusion. At the onset of angina these patients had similar ST-segment depression before and after GIK but when ST segments were assessed after GIK at the same exercise duration when angina had occurred during the control and post-S studies, there was significantly less ST depression (p less than 0.01). Of the remaining 7 patients exercise tolerance following GIK deteriorated in 3, remained unchanged in 2 and increased by 12 and 48 sec in 2 patients in comparison to post-S values. Comparison of post-GUK and post-S values for G, L and FFA for the whole group showed significantly lower resting values of FFA and post-exercise values of G following GIK infusion. The differences in clinical and circulatory responses between patients who improved and those who did not improve following GIK were not related to the angiographically determined severity of coronary artery disease or to GIK-induced metabolic changes. Results suggest that some patients with angina pectoris do benefit from GIK infusion but the response in a given patient to this therapeutic modality is unpredictable.

Adult↗
PubMed1978

Submitral annular left ventricular aneurysm--unusual echocardiographic and angiographic features.

A submitral annular left ventricular aneurysm in a Nigerian patient is described. The features consisted of an abnormal bulge on the left heart border with curvilinear calcification, an echo-free space behind the posterior left ventricular wall, and unusual angiographic appearance of the left circumflex coronary artery. The diagnosis was confirmed by pulmonary artery and left ventricular angiography. The patient underwent open heart surgery and a multiloculated submitral annular left ventricular aneurysm which was adherent to the pericardium was successfully resected.

Adult↗
PubMed1977

Hemodynamics at rest and during supine and sitting bicycle exercise in patients with coronary artery disease.

To access left ventricular function and compare pulmonary capillary wedge pressure and left ventricular end-diastolic pressure in the supine and sitting positions, 20 men with angina pectoris secondary to coronary artery disease underwent hemodynamic studies at rest and during exercise in the two positions. At rest the values for cardiac index, stroke index, systolic ejection rate index and left ventricular stroke work index were lower in the sitting position; heart rate, left ventricular end-diastolic pressure and pulmonary capillary wedge pressure were similar in the two positions. All patients experienced angina during both exercise periods. At angina during supine exercise, stroke index, systolic ejection rate index and left ventricular stroke work index did not increase significantly from the resting values. In contrast, during sitting exercise, significant increases in these variables were observed. Comparison of data during exercise revealed higher values for heart rate, mean systemic pressure, cardiac index, systolic ejection rate index, left ventricular stroke work index and rate-pressure product and lower values for mean pulmonary capillary wedge pressure (20 +/- 3 versus 27 +/- 3 [mean +/- standard error of the mean] mm Hg, P is less than 0.001), and left ventricular end-diastolic pressure (24+/- 3 versus 31 +/- 3 mm Hg, P is less than 0.02) in the sitting position; stroke index and S-T segment depression were similar during the two exercise periods. Four patients had insignificant increases in left ventricular filling pressure during both exercise periods. Of the 16 patients with abnormal left ventricular filling pressure during supine exercise, only 10 had a similar response during exercise in the sitting position. There was a good correlation between left ventricular end-diastolic pressure and mean pulmonary capillary wedge pressure at rest and during exercise in the two postures.

Adult↗