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Biomedical subjects

G Vijayaraghavan

Publications and source records attributed to G Vijayaraghavan.

At least 19 recordsLinked to original sources
PubMed2006

Reno-protective effect of N-acetyl cysteine in patients with impaired renal function undergoing coronary angiography and interventions.

BACKGROUND: The increasingly frequent use of contrast enhanced imaging for diagnosis or interventions in patients with CAD has generated concern about avoidance of contrast induced nephropathy (CIN). Reactive oxygen species have been shown to cause CIN. OBJECTIVES: Angiographic contrasts worsen the renal function in patients with renal failure. We studied the reno-protective action of the antioxidant N-Acetyl cysteine (NAC) in patients undergoing coronary procedures. METHODS: Retrospective analysis of 51 patients with elevated serum creatinine levels (> or = 15mg%) was done, 24 of whom received NAC prior to the procedure(NAC group) and 27 who did not (Non NAC group). NAC was administered in a dose of 400 mg twice daily for four doses starting on the day prior to the procedure. Both groups of patients were hydrated with 0.45% saline at 1 ml/kg/hr for 12 hours prior to and 12 hours following the procedure. Both groups were comparable with regard to age, sex, coronary risk profile, myocardial infarction history, left ventricular function and the drugs received. Serum urea and creatinine were measured on the day prior to and the day following the angiographic procedure. RESULTS: Nine out of 51 patients developed more than 0.5mg% rise in serum creatinine level; 1 in the NAC group and 8 in the non NAC group (p<0.05), 24 hours after injection of the contrast medium. In the NAC group mean serum creatinine level decreased from 1.94 +/- 0.56 to 1.67 +/- 0.56 and blood urea from 47.58 +/- 20 to 41.58 +/- 15.1. In the non NAC group serum creatinine increased from 1.75 +/- 0.31 to 1.98 +/- 0.56 and blood urea from 44.96 +/- 15.5 to 52.85 +/- 20.1 (p<0.05). This corresponds to an increase in creatinine clearance from 30ml/min to 35.92ml/min in the NAC group and a decrease from 34.42ml/min to 29.87ml/min in the non NAC group. There was no significant difference in the levels of sodium and potassium before and after the procedure in both the groups. CONCLUSION: We conclude that prophylactit administration of N-Acetyl Cysteine along with hydration diminishes the incidence of deterioration of renal function induced by contrast agents in patients with renal insufficiency during coronary angiographic procedures.

Acetylcysteine↗
PubMed1990

Pattern of cardiac calcification in tropical endomyocardial fibrosis.

Over a two-year period we investigated 55 patients with endomyocardial fibrosis, using two-dimensional echocardiography, color-coded echocardiography, and image intensifier fluoroscopy, to delineate the regional distribution of cardiac calcification. Thirty five patients (64%) were found to have calcification of the ventricular walls. Calcific deposits were seen in the right ventricle in 26(59%) patients and in the left ventricle in 16(44%) patients. All patients who showed calcification were in severe cardiac failure indicating late stage of the disease. When image intensifier fluoroscopy was taken as the gold standard, echocardiography had a sensitivity of 100% and a specificity of 98% in detecting cardiac calcification. The high incidence of calcification in the ventricular walls in the present study is apparently due to the systematic use of two-dimensional echocardiography and image intensifier fluoroscopy.

Adolescent↗
PubMed1989

Direct communication between the left pulmonary artery and the left atrium.

A 17-year-old patient was found to have cyanosis. A right-to-left shunt was suspected clinically and confirmed by noninvasive techniques such as perfusion lung scan and contrast echocardiography. Angiography showed this shunt to be between the left pulmonary artery and the left atrium. We believe this to be the first report of a hitherto undescribed congenital anomaly.

Adolescent↗
PubMed1986

Simplified echocardiographic measurement of the mitral anulus.

Postmortem, clinical, and experimental observations suggest an approximate elliptical shape for the mitral valve anulus, limiting the accuracy of single-diameter measurements in estimating annular area and circumference. A detailed method has been reported which uses six apical echocardiographic views at 30-degree rotational intervals to measure the mitral anulus, providing results comparable with pathologic and experimental reports. Annular data from nine normal subjects and 18 patients with dilated cardiomyopathy were analyzed to test a simplified measurement procedure. Assuming an elliptical shape, mitral annular area (MAA) and mitral annular circumference (MAC) were calculated by means of major (usually corresponding to the four-chamber view) and minor diameters from two orthogonal apical planes. Assuming a circular shape, MAA and MAC were also estimated by means of single annular diameters obtained from both an apical four-chamber and a parasternal long-axis view. Systolic and diastolic points were analyzed together, providing an n = 54 in the linear regressions. The two-plane results in MAA and MAC were nearly identical to those from the six-plane method, with very close correlation (r = 0.982 to 0.990). The single-plane results systematically overestimated MAA and MAC, with less correlation (apical, r = 0.943 to 0.963; parasternal, r = 0.852). Thus, while single-diameter measurements may correlate with global changes in annular size, the two-plane method represents a simplified but accurate method for estimating MAA and MAC in humans.

Echocardiography↗
PubMed1985

In vitro study of the pressure-velocity relation across stenotic orifices.

In a hand-driven, pulsatile in vitro model, the pressure-velocity relation across stenotic orifices was studied from simultaneous measurements recorded over a wide range of pressure and across different-sized orifices, individually and paired. Velocity spectra were recorded with continuous-wave Doppler ultrasound. In a rigid, noncompliant system, integrated instantaneous maximal velocities precisely register simultaneous integrated pressure gradients without measureable phase shift. Across stenotic orifices of 5 to 10 mm in diameter, the pressure-velocity relation is independent of orifice size for pressures extending from -30 to +240 mm Hg. The relation is quadratic and crosses 0. In this model, application of the simplified Bernoulli equation transforms the relation from curvilinear to linear with a bias toward the derived-pressure axis. In the presence of 2 different-sized orifices, the pressure-velocity relation remains constant, with a given pressure producing 2 identical velocities.

Animals↗
PubMed1985

Paradoxical deterioration of left ventricular asynergy after administration of nitroglycerin.

The effects of nitroglycerin on segmental asynergy were studied by 2-dimensional echocardiography. Forty-five patients with coronary artery disease and segmental wall motion abnormality at rest were examined, 31 with Q-wave and 14 with only ST-T abnormalities. Left ventricular (LV) echocardiograms were recorded from the LV apex in 4 planes, obtained by systematically rotating the transducer at 45 degrees intervals around the mitral office, using a mechanical device. Sixteen LV segments were analyzed in each patient on real-time display by 2 observers independently. The wall motion analysis was classified as normal, hypokinetic, akinetic or dyskinetic. Of 720 segments, 596 were agreed on by 2 observers in the assessment of wall motion before and after administration of nitroglycerin: 334 segments (56%) showed no change in wall motion, 206 (35%) showed improvement of wall motion and 56 (9%) showed worsening of myocardial asynergy after nitroglycerin. These data suggest that administration of nitroglycerin may result in unexpected worsening of segmental asynergy. This may be secondary to an adverse effect of a decrease in perfusion pressure in critically occluded arteries or may represent a coronary steal phenomenon.

Aged↗
PubMed1983

Echocardiographic features of tropical endomyocardial disease in South India.

Fifteen patients with tropical endomyocardial disease which had been proved angiographically were studied using M-mode and cross-sectional echocardiography to determine the extent to which specific features of this disease could be recognised by these non-invasive methods. Tethering of the posterior mitral valve leaflet to the ventricular wall in combination with areas of echo-dense material in the posterior left ventricular wall and associated papillary muscle appeared to be a constant diagnostic feature of this disease. Colour coding of regional echo amplitude showed high intensity echoes in a distribution corresponding closely to that of the fibrosis known to occur in this condition. Though M-mode echocardiography did not contribute diagnostic information, it was useful in defining the functional consequences of myocardial or mitral valve disease. Digitisation of records allowed a restrictive pattern of left ventricular filling to be observed. It was concluded that cross-sectional echocardiography, particularly when supplemented by colour coded amplitude processing, can make a confident non-invasive diagnosis of tropical endomyocardial disease and so could be useful in assessing its progression or response to treatment.

Adolescent↗
PubMed1983

A comparison of the clinical and cardiological features of endomyocardial disease in temperate and tropical regions.

This study was designed to compare the clinical and cardiological features of endomyocardial disease in temperate and tropical regions. Eleven patients were studied in the U.K., 47 in India and 8 in Brazil. The patients in the U.K. were older, with a male predominance, and they had a systemic illness: the hypereosinophilic syndrome. Half of these patients presented in the early necrotic stage of the disease, and all had biventricular involvement. On the other hand, patients in the tropical countries were younger, with an equal sex incidence, and were from poor, malnourished communities with heavy parasite loads, especially filariasis in India. None presented in the early necrotic stage of the disease and a quarter had isolated right or left ventricular disease. In order to account for these differences between patients in temperate and tropical regions with endomyocardial disease, it was proposed that the nature of the underlying disease and the rate at which endomyocardial lesions develop, determine the clinical features of this disorder. In temperate climates eosinophil granule toxins may produce a rapidly progressive form of the disease in patients with the hypereosinophilic syndrome, whereas the disease may take longer to develop in patients in tropical climates, who have a less marked eosinophilia due to parasitic infections.

Adolescent↗
PubMed1977

Rheumatic aortic stenosis in young patients presenting with combined aortic and mitral stenosis.

This report describes 30 patients under the age of 30 years with rheumatic aortic stenosis, presenting with combined aortic and mitral stenosis. Three patients had additional tricuspid stenosis. Twenty-eight patients gave a history of rheumatic polyarthritis. The diagnosis was confirmed by right and left heart catheterisation in all. The murmur of aortic stenosis was not initially present in 8 out of 10 patients in congestive heart failure. Aortic valve calcification was not seen. Cineangiography showed a tricuspid aortic valve in all, unlike congenital aortic stenosis. A unique feature of this group was the raised pulmonary vascular resistance in 87 per cent of the patients. The present study shows that patients in India developing aortic stenosis after rheumatic fever do so early in the natural history of the disease.

Adolescent↗
PubMed1977

Left ventricular endomyocardial fibrosis in India.

Clinical, radiological, electrocardiographic, haemodynamic, and cineangiographic features of left ventricular endomyocardial fibrosis are described in 8 patients seen during the 10-year period 1965-1975. Exertional dyspnoea was the commonest presenting symptom. Mild to moderate cardiomegaly was often present. The apex beat was never forcible. A loud third heart sound over the apex and an apical early systolic murmur with late systolic decresendo were characteristic of this desease. Chest X-rays films showed left atrial enlargement and pulmonary venous congestion. A pronounced rise in left ventricular end-diastolic pressure, severe pulmonary hypertension, and low cardiac index were seen in 6. Ventriculography showed an irregular, poorly contracting left ventricle with areas of dyskinesis and large end-systolic volume. Mitral regurgitation, when present, was not severe.

Adolescent↗