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Biomedical subjects

R Narang

Publications and source records attributed to R Narang.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

Acute hemodynamic effects of tocainide in patients undergoing cardiac catheterization.

To characterize the acute hemodynamic effects of tocainide hydrochloride, a new antiarrhythmic agent, 11 patients undergoing diagnostic cardiac catheterization were given intravenous infusions of the drug for 15 minutes at rates of 0.50 (six patients) or 0.75 (five patients) mg/kg/min. The hemodynamic status of these subjects was determined before, during, and for 15 minutes after treatment, and blood levels of tocainide were followed during and after treatment. Tocainide blood levels at the end of the infusions were 14.9 +/- 1.6 microgram/ml (S.E.) and 15 minutes later were 6.0 +/- 0.7 microgram/ml. In these subjects treatment was not associated with significant changes in Ao or PCW, but it was associated with a statistically significant but small decrease in LV dp/dt. At the same time, LVED was not significantly elevated. Treatment was also accompanied by small increases in PA diastolic and mean pressures, but RA and RV were unchanged. Significant changes were not seen in HR, CO, CI, SV, SVR, or PVR. Thus, the intravenous infusion of 0.50 and 0.75 mg/kg/min of tocainide for 15 minutes produced small but statistically significant depression of left ventricular function without producing changes in CO or clinical evidence of congestive heart failure.

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

Apolipoprotein(a) polymorphism and its association with plasma lipoprotein(a) levels: a north Indian study.

Elevated levels of lipoprotein(a) has been regarded as an independent risk factor for coronary, peripheral and cerebral atherosclerosis. The enormous intra-personal variation in the plasma concentration of lipoprotein(a) is almost entirely controlled by the apolipoprotein(a) i.e. gene locus on the chromosome 6q 26-27. The apolipoprotein(a) molecule is highly polymorphic and is known to exist in multiple, genetically determined isoforms. These polymorphisms may be responsible for difference in promoter activity, variable size of apolipoprotein(a) and thereby variation in plasma lipoprotein(a) concentration. We studied the effect of two types of polymorphisms, (i) variation in length of the pentanucleotide repeat in the 5' flanking region starting -1373 bp upstream of AUG codon, and (ii) the Kringle-4 type 2 size polymorphism, on plasma lipoprotein(a) levels in North Indian population. The study group consisted of 88 angiographically assessed male coronary artery disease patients (age range 30-70 years) and 83 age- and sex-matched healthy controls. The pentanucleotide repeat polymorphism was analysed using polymerase chain reaction. In all, 8/11 pentanucleotide repeat isoforms were observed. Using SDS-agarose gel electrophoresis and immunoblotting isoforms having 12-50 Kringle-4 type 2 repeats were detected. Our study indicates a strong association of elevated plasma lipoprotein(a) concentration with coronary artery disease. An inverse correlation was seen between lipoprotein concentration and isoform size for both the pentanucleotide repeat polymorphism and the Kringle-4 type 2 polymorphisms; statistically significant difference (p = 0.001) was, however, observed only for the later.

Adult↗
PubMedDate not supplied

Percutaneous transseptal mitral commissurotomy in pregnant women with critical mitral stenosis.

BACKGROUND: Percutaneous transseptal mitral commissurotomy has been successfully performed in selected pregnant patients with severe symptomatic mitral stenosis. Its safety and efficacy needs to be evaluated in a large number of cases. METHODS AND RESULTS: Percutaneous transseptal mitral commissurotomy was performed in 85 severely symptomatic (New York Heart Association functional class III or IV) pregnant women aged 22.7+/-4.1 years (range 18-39 years) with critical mitral stenosis at 24.8+/-4.7 weeks (range 20-34 weeks) of gestation. Percutaneous valvotomy was performed using a flow-guided Inoue balloon in all the patients. The procedure was considered successful in 80 (94%) patients. The hemodynamic mean end-diastolic gradient decreased from 26.7+/-6.8 mm Hg (range 16-35 mmHg) to 4.5+/-3.8 mmHg (range 0-14 mmHg) (p<0.001). The mean diastolic gradient decreased from 29.1+/-9.1 mmHg (range 18-38 mmHg) to 7.2+/-4.1 mmHg (range 4.1-18 mmHg) (p<0.001). The mean mitral valve area assessed by echocardiography increased from 0.75+/-0.5 cm2 (range 0.4-1.0 cm2) to 2.0+/-0.5 (range 1.0-2.7 cm2) (p<0.001). The mean fluoroscopy time was 3.6+/-3.2 minutes. The results of the mitral valvotomy were considered suboptimal in 4 patients. Mitral regurgitation increased by 1 grade in 16 patients and more than 2 grades in 2 patients. One patient developed pericardial tamponade during the procedure and was managed by catheter drainage. Percutaneous mitral valve dilatation was then successfully performed in this patient. No fetal abortion occurred after the procedure. CONCLUSIONS: The results of this study indicate that percutaneous transseptal mitral commissurotomy is a safe and effective procedure for severe symptomatic mitral stenosis in pregnancy.

Adolescent↗