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Biomedical subjects

V S Narain

Publications and source records attributed to V S Narain.

At least 19 recordsLinked to original sources
PubMed2006

Diastolic and systolic right ventricular dysfunction precedes left ventricular dysfunction in patients paced from right ventricular apex.

BACKGROUND: Cardiac dysfunction after right ventricular (RV) apical pacing is well known but its extent, time frame of appearance and individual effect on left ventricular (LV), RV systolic and diastolic parameters has not evaluated in a systematic fashion. METHODS: Patients with symptomatic bradycardia and ACC-AHA Class I indication for permanent pacemaker implantation (PPI) were implanted a single chamber (VVI) pacemaker. They were followed prospectively by echocardiographic examination which was done at baseline, 1 week, 1 month and 6 months after implantation. Parameters observed were chamber dimensions (M-line), chamber volumes, cardiac output (modified Simpson's method), systolic functions (ejection fraction, pre-ejection period, ejection time and ratio) and diastolic functions( isovolumic relaxation time & deceleration time) of left and right heart. RESULTS: Forty eight consecutive patients (mean age 65.6+/-11.8 yrs, 66.7% males, mean EF 61.82+/-10.36%) implanted a VVI pacemaker were enrolled in this study. The first significant change to appear in cardiac function after VVI pacing was in diastolic properties of RV as shown by increase in RV isovolumic relaxation time (IVRT) from 65.89+/-15.93 to 76.58+/-17.00 ms,(p<0.001) at 1week and RV deceleration time (DT) from 133.84+/-38.13 to 153.09+/-31.41 ms, (p=0.02) at 1 month. Increase in RV internal dimension (RVID) from 1.26+/-0.41 to 1.44+/-0.44, (p<0.05) was also noticed at 1 week. The LV diastolic parameters were significantly altered after 1 month with increase in LV-IVRT from 92.36+/-21.47 to 117.24+/-27.21ms, (p<0.001) and increase in LV DT from 147.56+/-31.84 to 189.27+/-28.49ms,(p<0.01). This was followed by LV systolic abnormality which appeared at 6 months with an increase in LVPEP from 100.33+/-14.43 to 118.41+/-21.34ms, (p<0.001) and increase in LVPEP/LVET ratio from 0.34+/-0.46 to 0.44+/-0.10, (p<0.001)]. The reduction in LV EF was manifested at 6 months falling from 61.82+/-10.36% to52.52+/-12.11%, (p<0.05) without any significant change in the resting cardiac output. CONCLUSION: The present study shows that dysfunction of right ventricle is the first abnormality that occurs in VVI paced patients, which manifests by 1 week followed by LV dysfunction which starts appearing by 1 month and the diastolic dysfunctions precede the systolic dysfunction in both ventricles.

Journal Article↗
PubMed2003

Homocysteine and lipid levels in young patients with coronary artery disease.

AIMS AND OBJECTIVES: Indians are more prone to premature coronary artery disease (CAD). The importance of homocysteine as a risk factor for CAD in Indian patients needs to be recognized. The aim of this study was to note the independent association of this novel risk factor with traditional ones in young CAD patients. METHODOLOGY: This study included 51 patients, < 45 years of age, with proven CAD. They were further divided into two subgroups based on their lipid profile. Group A (n = 30) hyperlipidemic CAD patients and Group B (n = 21) normolipidemic CAD patients. They were compared with 15 age and sex matched healthy controls. Plasma homocysteine was assayed using high pressure liquid chromatography, fasting lipid profile and other risk factors were compared. RESULTS: The mean level of homocysteine in patient group was 27.8 +/- 13.11 nmol/ml. In subgroup A it was 28.86 +/- 13.02 while in subgroup B it was 26.46 +/- 13.44. In the patient group (n = 51), 37 (72.55%) had homocysteine levels greater than 18 nmol/ml. In the control group mean homocysteine was 13.22 nmol/ml +/- 7.36 and only 4 (26.77%) had homocysteine levels greater than the cut-off. CONCLUSIONS: Thus in spite of some baseline variations, plasma homocysteine emerged as a significant (p = 0.0009, OR 6.05) independent risk factor for young CAD patients and was not altered by the baseline lipid profile of the patient. Therefore it should be evaluated in all young patients of CAD in the absence of traditional risk factors.

Adult↗
PubMed2001

Silent ischemic interval on exercise test is a predictor of response to drug therapy: a randomized crossover trial of metoprolol versus diltiazem in stable angina.

BACKGROUND AND HYPOTHESIS: There is no method available to predict the relative antianginal efficacy of beta blockers and calcium-channel antagonists. The present study was undertaken to assess the role of silent ischemic interval (SII) on exercise treadmill test (ETT) as a predictor of response to therapy with metoprolol and diltiazem in patients with stable angina. METHODS: Thirty-four patients with stable angina were divided into two groups depending upon the presence or absence of an SII gap of at least 1 min between onset of ST depression and appearance of angina on ETT. Metoprolol (50-100 mg twice daily) and diltiazem (60-120 mg three times daily) were randomly assigned for 6 weeks to patients in each group, and then patients were crossed over for further 6 weeks after a washout period of 2 weeks. Antianginal efficacy was assessed by clinical and exercise parameters. RESULTS: In patients with SII, the clinical responder rate was better with metoprolol than with diltiazem (90 vs. 60%, respectively), and on ETT, metoprolol produced significant improvement in the total exercise time (p< 0.01), time to 1 mm ST depression (p <0.01), time to angina (p <0.01), and a significant decrease in peak rate-pressure product (p<0.001), whereas diltiazem had no significant effect on exercise parameters. However, in patients without SII, metoprolol and diltiazem had a similar clinical responder rate (57%), and both produced a significant increase in total exercise time (p < 0.01), time to 1 mm ST depression (p < 0.01), and time to angina (p < 0.01). In addition, metoprolol had a significant effect on peak rate-pressure product (p < 0.001). CONCLUSION: Silent ischemic interval on ETT can be a predictor of response to antianginal therapy in stable angina, as patients with SII respond better to metoprolol and those without SII respond equally to both metoprolol and diltiazem.

Adrenergic beta-Antagonists↗
PubMed1998

Left ventricular diastolic collapse in low-pressure cardiac tamponade.

A case of systemic hypotension with volume depletion not responding to intravenous fluids was found to have features of cardiac tamponade on two-dimensional (2-D) echocardiography. Intracardiac pressures were normal on cardiac catheterization. An interesting observation was the presence of left ventricular (LV) collapse on 2-D echocardiography. To the authors' best knowledge, such a case of low pressure cardiac tamponade with LV collapse has not been reported earlier.

Adolescent↗
PubMed1990

Intravenous streptokinase in the management of a subset of patients with unstable angina: a randomized controlled trial.

We report the results of a randomized controlled trial of intravenous streptokinase in a subset of patients with unstable angina. Seventy-six patients were admitted with prolonged (more than 20 minutes) angina at rest of less than 3 weeks onset. Fifty-two patients continued to have more than 3 episodes of prolonged angina in 48 hours on medical therapy with metoprolol, isosorbide dinitrate, nifedipine and intravenous nitroglycerin. Forty-eight patients consented to enter the study and were randomized into two groups. The first group, of 24 patients, received 1.5 million units of streptokinase infusion and the second group, also of 24 patients, received a placebo. Pain relief within 48 hours was achieved in 19/24 (79.1%) patients after streptokinase infusion as compared to 9/24 (37.5%) of the controls (P less than 0.05). Approximately 90% (17/19) of patients responding to streptokinase therapy were relieved of chest pain within the first six hours as against none in the controls. The incidence of acute myocardial infarction within six months was 12.5% (3/24) in those receiving streptokinase and 25% (6/24) in the controls. Mortality at six months stood at 8.33% (2/24) in the treated patients and 16.6% (4/24) in the controls. Intravenous streptokinase thus appears to be of benefit in patients with angina at rest of recent onset which does not respond to conventional medical therapy.

Angina Pectoris↗
PubMedDate not supplied

Accelerated infusion of streptokinase in acute myocardial infarction results in better TIMI flow grade in infarct-related artery.

Bolus followed by rapid infusion of tissue plasminogen activator results in higher grade of TIMI flow in infarct-related artery as compared to slow infusion. In the present study, an accelerated regimen of streptokinase given over 15 minutes was compared with conventional infusion over one hour in 47 patients presenting within 12 hours of acute myocardial infarction. Forty-seven patients (44 males, 3 females; mean age 54.0 +/- 1.1 years) were randomly allocated to receive 1.5 million units of streptokinase either over 15 minutes (group 1, n = 24) or over one hour (group 2, n = 23) at a mean interval of 5.4 +/- 3.6 hours after onset of symptoms. All the patients received aspirin and intravenous heparin (1000 U/hr) for 96 hours after thrombolysis. Coronary angiography was performed in 43 patients (22 in group 1, 21 in group 2) prior to discharge from the hospital (mean 7 +/- 2.1 days after acute myocardial infarction) and patency of the infarct-related artery and grade of TIMI flow were determined. Infarct-related artery was patent (TIMI 2/3 flow) in 19 (86.4%) patients in group 1 as compared to 12 (57.1%) in group 2 (p < 0.05). TIMI grade 3 flow in the infarct-related artery was present in 13 (59.1%) in group 1 as compared to 7 (33.3%) in group 2 (p = 0.1). There was no significant difference between group 1 and 2 in time of presentation (mean 5.3 +/- 3.9 hrs vs 5.5 +/- 3.2 hrs), time to needle in hospital (25.6 +/- 11.2 min vs 26.3 +/- 6.2 min), site of infarct (anterior myocardial infarction 12 in group 1 vs 11 in group 2), relief of pain at 90 min (13 vs 12), more than 50 percent reduction of ST elevation at 90 minutes (17 vs 12) and left ventricular ejection fraction (48.8 +/- 9.1% vs 49.8 +/- 16.0%), respectively. Streptokinase was well tolerated in both the groups, although hypotension was more common with the accelerated regimen (5 in group 1 vs 3 in group 2; p = NS). Thus, 'accelerated' streptokinase given over 15 minutes in patients presenting within 12 hours of acute myocardial infarction is well tolerated and results in higher grades of TIMI flow in the infarct-related artery as compared to the "conventional" one-hour infusion regimen.

Adult↗
PubMedDate not supplied

Megadose heparin and streptokinase produce similar TIMI 3 flow at discharge in patients of acute myocardial infarction presenting between 7-12 hours.

The present study was undertaken to assess the impact of megadose heparin bolus on angiographic patency of infarct-related artery in patients of acute myocardial infarction presenting between 7-12 hours and to compare it with streptokinase. Forty-seven patients (27 males, mean age 58.1 +/- 9.6 years) of acute myocardial infarction between 7-12 hours of onset of chest pain were randomised to receive either megadose heparin bolus (300 IU/kg body weight, group 1, n = 24; or streptokinase 1.5 million units over one hour, group 2, n = 23). Parameters noted were: relief of pain at 90 minutes, 50 percent or more resolution of ST segment at 90 minutes, TIMI grade flow and left ventricular ejection fraction at discharge. Mean age (59.0 +/- 12.9 years in group 1; 57.2 +/- 8.1 years in group 2), mean time to drug (7.5 +/- 1.3 hours in group 1; 7.8 +/- 1.6 hours in group 2), site of anterior wall infarction (12 in group 1, 10 in group 2), relief of pain at 90 minutes (15 in group 1, 14 in group 2) and more than 50 percent resolution of ST segment elevation at 90 minutes (12 patients in each group) were similar. On coronary angiography performed in 42 patients (21 in each group) at a mean interval of 7.2 +/- 1.3 days after acute myocardial infarction, TIMI grade 3 flow was seen in 7 (33.3%) patients in each group and TIMI grade 2/3 flow was also similar in both the groups (p = NS). No major bleed occurred in either group. We conclude that heparin given as a megadose bolus produces similar TIMI 3 flow in infarct-related artery as compared to streptokinase in acute myocardial infarction patients presenting between 7-12 hours.

Aged↗
PubMedDate not supplied

Left ventricular pacing through coronary sinus tributaries: initial experience.

BACKGROUND: Left ventricular pacing is increasingly being used as a part of biventricular pacing in congestive heart failure but data on safety, feasibility, reliability and lead maturation are sparse. METHODS AND RESULTS: Seventeen patients (13 males and 4 females) with persistent symptomatic degenerative complete heart block underwent temporary left ventricular pacing by a left subclavian puncture through the coronary sinus to its tributaries using a unipolar permanent pacing lead connected to an external pulse generator. The left ventricular pacing was done for two weeks. Permanent right ventricular apical pacing was also done at the same time through a right cephalic vein cut-down or subclavian puncture and the pacing rate was kept below that of the initial left ventricular pacing rate. Pacing parameters of the left and right ventricles were assessed at the time of implantation and at two weeks. Out of 17 patients, left ventricular pacing was successful in 11 (67.7%) patients. The time taken for the total procedure was 56+/-18.1 min. Lead displacement was noted in one patient without loss of pacing. At the time of implant and after two weeks, left ventricular pacing threshold, impedance, R wave height and slew rate were not different as compared to right ventricular pacing. Holter recording for 24 hours revealed regular left ventricular pacing at the end of two weeks in all patients. CONCLUSIONS: The present study shows that left ventricular pacing through coronary sinus tributaries is feasible and reliable. Acute and subacute maturation of left ventricular pacing are similar to right ventricular apical pacing.

Aged↗
PubMedDate not supplied

Lipoprotein (a) and lipid levels in young patients with myocardial infarction and their first-degree relatives.

BACKGROUND: Studies among emigrant Indians have stressed the role of a powerful genetic factor, lipoprotein (a), in the causation of premature coronary artery disease. This study was carried out to assess lipoprotein (a) and lipid levels in 50 consecutive young north Indian patients (age less than 45 years, mean age 39+/-3.7 years) with myocardial infarction, their first-degree relatives (n=125, mean age 36+/-16 years), and age- and sex-matched controls (n=50, mean age 34+/-6.9 years). METHODS AND RESULTS: Blood samples for lipid estimation were taken within 24 hours of myocardial infarction and after overnight fasting for twelve hours. Lipoprotein (a) levels were estimated by the ELISA technique using preformed antibodies while lipid levels were estimated by kits using the colorimetric method. All were male patients. The mean lipoprotein (a) level was 22.28+5.4 mg/dl in patients, 13.88+5.19 mg/dl in their first-degree relatives and 9.28+22.59 mg/dl in controls. In addition, it was significantly higher in young patients with myocardial infarction and their relatives as compared to controls (p<0.001 for patients v. controls and p<0.05 for relatives v. controls). There was no significant difference in the levels of total cholesterol and low-density lipoprotein cholesterol among the three groups. High-density lipoprotein cholesterol was significantly lower in young patients with myocardial infarction (30.16+/-9.45 mg/dl) and their first-degree relatives (33.28+/-8.45 mg/dl) as compared to controls (46.8+/-8.04 mg/dl) (p<0.001 for patients v. controls and p<0.01 for relatives v. controls). Triglyceride levels were significantly higher in patients as compared to controls (202+/-76 mg/dl v. 149 + 82.99 mg/dl, p<0.05). Smoking was more prevalent in young patients with myocardial infarction as compared to controls (44% v. 36%, p<0.05). CONCLUSIONS: Smoking, high lipoprotein (a) and triglyceride levels and low high-density lipoprotein levels may be important risk factors for coronary artery disease in the younger population; also, there is familial clustering of high lipoprotein (a) levels in first-degree relatives of young patients with myocardial infarction.

Adult↗
PubMedDate not supplied

Short-term (48 hours) versus long-term (7 days) antibiotic prophylaxis for permanent pacemaker implantation.

BACKGROUND: Infection following permanent pacemaker implantation is a dreaded complication. Antibiotic prophylaxis for 1-10 days at the time of implant has been used in the past but there is no consensus regarding its duration. We carried out a prospective, randomized study of two durations of antibiotic prophylaxis to determine which one was more effective. METHODS AND RESULTS: One hundred and seventy-eight patients undergoing permanent pacemaker implantation for the first time were randomized to receive short duration (group A, n = 8 8) or longer duration (group B, n = 90) antibiotic prophylaxis for 2 days and 7 days, respectively. Patients in both groups received cloxacillin 2 g 2 hours prior to the procedure followed by ampicillin and cloxacillin (50 mg/kg/day in 4 divided doses) and gentamicin (3 mg/kg/day in 2 divided doses) for the respective duration. Patients were followed up for 1-17.3 months (9.3 +/- 1.8 months) in group A and 1-16.5 months (8.9 +/- 2 months) in group B. One patient in group B had an infection at the pacemaker site and two patients in each group had to undergo reimplantation due to pus in the pocket. There was no significant difference in the primary end-point in both groups. CONCLUSIONS: A short course (48 hours) of antibiotic prophylaxis following permanent pacemaker implantation is as effective as a longer course (7 days).

Anti-Bacterial Agents↗
PubMedDate not supplied

Modified cephalic vein guide wire technique for permanent pacemaker implantation.

This report describes a modified cephalic vein guide wire technique used for implantation of 18 consecutive pacemakers using bipolar leads. The modified technique appears to be a safe and simple procedure for single chamber permanent pacing. Its use may also be extended in implanting dual chamber pacemakers.

Adult↗
PubMedDate not supplied

Sites of right ventricular outflow tract obstruction in tetralogy of Fallot--a retrospective study.

Fifty one angiographically proved cases of tetralogy of Fallot (TOF) in the age group of 5-50 years were analysed retrospectively for the level(s) of right ventricular outflow tract (RVOT) obstruction. Mean age was 18.1 +/- 11 yrs. Subvalvular stenosis was found to be the commonest site of RVOT obstruction in 49 (96.1%) patients. Evidence of valvular pulmonary stenosis was seen quite commonly (42/51, 83.9% cases), mostly in association with obstruction at other sites. Supravalvular stenosis was also seen in 17 (33.3%) cases. Higher incidence of pulmonary valvular involvement in patients with TOF, in higher average age of patient population may represent valvular involvement to be an acquired phenomenon.

Adolescent↗
PubMedDate not supplied

Prostaglandin E1 (PGE1): effect on the human fibrinolytic system.

The in vitro effect of prostaglandin E1 on the fibrinolytic process was assessed in 30 patients with acute myocardial infarction (MI) using Thrombin Time (TT) and Euglobulin Clot Lysis time (ECLT) as parameters. Thrombin time was shortened and ECLT was prolonged (p less than 0.001) in acute MI as compared to thirty age and sex matched controls. In both groups, preincubation of sera with PGE1 (3.3 micrograms/ml) produced prolongation of TT and shortening of ECLT (p less than 0.001). Thus PGE1, which is a naturally occurring vasodilator and antiplatelet agent, also appears to have fibrinolytic activity.

Adult↗