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Biomedical subjects

G Das

Publications and source records attributed to G Das.

144 records · Page 8Linked to original sources
PubMed1976

Left axis deviation: a spectrum of intraventricular conduction block.

The effects of left axis shift (greater than -30 degrees) on intraventricular conduction time (IVCT) were studied in 63 subjects in whom electrocardiograms before and after appearance of the left axis shift were available. Subjects with electrocardiographic evidence of left or right ventricular hypertrophy, left or right bundle branch block, myocardial infarction, pre-excitation and those receiving antiarrthymic drugs were excluded. The IVCT increased by an average of 25 msec when the QRS axis shifted to -30 degrees or beyond. When the individual AQRS was related to the IVCT a linear correlation (r = -0.8) was observed. It appears that a continuum relation between the AQRS and the IVCT exists throughout the counterclockwise range of +90 degrees to -90 degees. In all leftward shifts in AQRS from from +90 degrees there is a prolongation in IVCT. Our observations indicate that all leftward shifts in AQRS, including the extreme left axis shift (left anterior hemiblock), represent a spectrum of intraventricular conduction block.

Adult↗
PubMed1975

New observations on the effects of atropine on the sinoatrial and atrioventricular nodes in man.

Previous observations of slowing of the heart rate after administration of atropine in doses smaller than 0.4 mg and recent reports of development of rhythm disorders in patients with acute myocardial infarction given atropine prompted us to evaluate systematically the effects of various doses of atropine (0.1 to 0.8 mg) on the response of the sinoatrial (S-A) and atrioventricular (A-V) nodes in healthy volunteers. The response of the S-A node to atropine was characteristically bimodal, slowing at smaller doses and accelerating at larger doses. In contrast, the A-V node showed acceleration of conduction in response to all doses of atropine used. A hypothesis based on current understanding of the electrophysiologic parameters governing impulse formation and impulse conduction is advanced to explain the apparent paradox in the S-A and A-V nodal responses to small doses of atropine. The results suggest the need for caution and continuous rhythm monitoring when giving atropine to patients with acute myocardial infarction.

Adult↗
PubMedDate not supplied

Effect of the balloon-anulus ratio on the intermediate and follow-up results of pulmonary balloon valvuloplasty.

Pulmonary balloon valvuloplasty (PBV) is an effective method to treat congenital valvular pulmonic stenosis, but the ideal balloon-anulus ratio (BAR) for this procedure remains unclear. We studied 71 procedures where BARs of 1.0-1.5 were used, since it has been shown that a ratio of < 1.0 is less effective and that of > 1.5 may produce more complications. A curvilinear relation was found between BAR and the fractional fall in haemodynamic parameters reflecting stenosis severity, both immediately after dilatation and at follow-up. Best results were observed with a BAR of 1.25, with progressive worsening on either side of this ratio. The relationship remained significant in multiple regression analysis involving age, sex and baseline haemodynamic variables. The data show that a BAR of 1.25 is probably the ideal ratio for PBV.

Adolescent↗
PubMedDate not supplied

In vitro micropropagation of Lawsonia inermis (Lythraceae).

A successful protocol was developed for mass propagation of Lawsonia inermis Linn., an important medicinal plant. Multiple shoots were induced in apical and axillary meristems derived from mature explants of L. inermis on Murashige and Skoog (1962) medium supplemented with 0.25 mg/l 6-benzylaminopurine (BA), 0.25 mg/l Kinetin (Kn), 0.5 mg/l ascorbic acid and 3% (w/v) sucrose. The rate of multiplication was higher when the cultures were incubated under continuous light rather than the 14 hr photoperiod. Rooting was readily achieved upon transferring the microshoots onto MS basal semi-solid medium supplemented with 0.25 mg/l indole-3-butyric acid (IBA) after ten days of culture. Micropropagated plantlets were acclimatized and successfully grown in soil.

Acclimatization↗
PubMedDate not supplied

Profile of coronary artery disease in Indian women: correlation of clinical, non invasive and coronary angiographic findings.

Clinical and risk factor profile of 101 consecutive female patients subjected to coronary angiography was analysed. Coronary angiography showed single vessel disease (SVD) in 15.8 per cent, double vessel disease (DVD) in 12.9 per cent, triple vessel disease (TVD) in 39.6 per cent and normal coronary arteries (NC) in 30.7 per cent. Risk factor profile in patients with angiographic coronary artery disease (group II) included hypertension (HT) in 52.9 per cent, diabetes mellitus (DM) in 44.3 per cent, post menopausal state in 84.3 per cent, positive family history in 51.4 per cent, obesity in 58.3 per cent, low density and high density lipoprotein ratio (LDL/HDL) more than 3.0 in 58 per cent and smoking in 4.3 per cent. Risk factors in 31 patients with NC (group I) included HT in 29 per cent, DM in 6.5 per cent, positive family history in 45.2 per cent, obesity in 45.2 per cent, post menopausal state in 48.4 per cent, LDL/HDL ratio more than 3.0 in 30 per cent and smoking in none. The clinical presentation in group II was unstable angina in 64.3 per cent, stable angina pectoris in 24.3 per cent, myocardial infarction in 4.3 per cent and atypical chest pain in 2.8 per cent. In group I half the patients presented with atypical chest pain. The other modes of presentation included unstable angina 25.8 per cent, stable angina pectoris in 16.2 per cent and myocardial infarction in 6.5 per cent. Predictive value of exercise electrocardiography (Ex ECG) or exercise radionuclide studies (Ex RNU) was 61.7 and 68.4 per cent respectively. DM, post-menopausal state and LDL/HDL ratio more than 3 were significant risk factors in women.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Echocardiographic assessment of the size of aortic and pulmonary valve annulus before balloon valvoplasty.

Two dimensional echocardiographic measurements of the size of aortic and pulmonary valve annulus were made in 60 patients before balloon valvoplasty and compared to the angiographic measurements. Aortic valve annulus was measured in 34 patients (26 with valvar aortic stenosis and 8 with discrete subaortic stenosis) in the parasternal long axis or apical 5-chamber views. The pulmonary valve annulus was measured in 26 patients with valvar pulmonary stenosis (PS) in the parasternal short axis view of the right ventricular outflow view. The visualization of the annulus was good in all except 2 patients with valvar PS. Angiographic measurements of the aortic and pulmonary valve annulus were made in aortic root and right ventricular angiograms respectively, taken in both right and left anterior oblique views. There was an excellent correlation between the measurements of the annulus size by the two techniques (r value for pulmonary valve 0.91; for aortic valve 0.96; over all 0.94). Echocardiography can accurately measure valve annulus size and help in choosing balloon dilatation catheter of appropriate size before the valvoplasty procedure.

Adolescent↗