Search PubMed⌕ Search

Biomedical subjects

V Paul

Publications and source records attributed to V Paul.

At least 19 recordsLinked to original sources
PubMed2006

Predicting mortality and rehospitalization in heart failure patients with home monitoring--the Home CARE pilot study.

The increasing worldwide prevalence of heart failure is associated with numerous and protracted hospital admissions. The multidisciplinary team approach together with telemonitoring aims at reducing the number of rehospitalizations, length of hospital stay, and mortality rates. Novel cardiac resynchronization therapy (CRT) devices have a Home Monitoring capability, offering wireless, everyday transfer of the essential status and therapy data to the attending physician. The transmitted data include potential predictors of death or hospitalization, such as the onset of atrial and ventricular arrhythmias, duration of physical activity, mean heart rates over 24 h and at rest, percentage of CRT delivered, and lead impedances. We present here interim results of the prospective, longitudinal, multicenter Home CARE Phase 0 study, conducted in 123 patients (age: 67+/-9 years, 83% male) with clinical indication for CRT. Twenty-nine patients (24%) received a CRT pacemaker, 52 (42%) a prophylactic implantable cardioverter defibrillator (ICD), and 42 (34%) had other ICD indications. All devices have an integrated Home Monitoring feature. In a mean (interim) follow-up period of 3 months (9194 observational days), 11 unplanned rehospitalizations of cardiovascular etiology and 9 deaths occurred. In 70% of the rehospitalization events, the retrospective analysis of transmitted data via Home Monitoring revealed an increase in mean heart rate at rest and in mean heart rate over 24 h within 7 days preceding hospitalization. A decrease in the percentage of CRT was observed in 43% and a reduction in the patients' daily activity in 30% of rehospitalized patients. These interim findings suggest that Home Monitoring data may predict events leading to hospitalization and encourage further research.

Activities of Daily Living↗
PubMed2004

Left ventricular pacing minimizes diastolic ventricular interaction, allowing improved preload-dependent systolic performance.

BACKGROUND: Left ventricular (LV) pacing improves hemodynamics in patients with heart failure. We hypothesized that at least part of this benefit occurs by minimization of external constraint to LV filling from ventricular interaction. METHODS AND RESULTS: We present median values (interquartile ranges) for 13 heart failure patients with LV pacing systems implanted for New York Heart Association class III/IV limitation. We used the conductance catheter method to measure LV pressure and volume simultaneously. External constraint was measured from the end-diastolic pressure-volume relation recorded during inferior vena caval occlusion, during LV pacing, and while pacing was suspended. External constraint to LV filling was reduced by 3.0 (4.6 to 0.6) mm Hg from 4.8 (0.6 to 7.5) mm Hg (P<0.01) in response to LV pacing; effective filling pressure (LV end-diastolic pressure minus external constraint) increased by 4.0 (2.2 to 5.8) mm Hg from 17.7 (13.3 to 22.6; P<0.01). LV end-diastolic volume increased by 10 (3 to 11) mL from 238 (169 to 295) mL (P=0.01), whereas LV end-systolic volume did not change significantly (-1 [-2 to 3] mL from 180 [124 to 236] mL, P=0.97), which resulted in an increase in stroke volume of 11 (5 to 13) mL from 49 (38 to 59) mL (P<0.01). LV stroke work increased by 720 (550 to 1180) mL . mm Hg from 3400 (2110 to 4480) mL . mm Hg (P=0.01), and maximum dP/dt increased by 120 (2 to 161) mm Hg/s from 635 (521 to 767) mm Hg/s (P=0.03). CONCLUSIONS: This study suggests a potentially important mechanism by which LV pacing may produce hemodynamic benefit. LV pacing minimizes external constraint to LV filling, resulting in an increase in effective filling pressure; the consequent increase in LV end-diastolic volume increases stroke volume via the Starling mechanism.

Aged↗
PubMed2004

Biventricular pacing in heart failure.

Optimal pharmacological therapy for heart failure improves patients' prognosis and symptoms. Despite this, the long-term prognosis for these patients is very poor and symptoms are debilitating. Biventricular pacing, or resynchronization therapy, should be considered for patients who remain symptomatic despite optimal therapy and have evidence of dyssynchrony.

Cardiac Pacing, Artificial↗
PubMed2004

High-dose anti-snake venom versus low-dose anti-snake venom in the treatment of poisonous snake bites--a critical study.

OBJECTIVES: To asses the optimum dose of anti-snake venom to treat snake bites cases effectively. This is particulary relevant in the present scenario when the cost of anti-snake venom ( Serum Institute of India) has gone up to nearly Rs. 400 per vial and the cross-section of people usually affected belong to the poor socioeconomic class. METHODOLOGY: One hundred snake bite cases with envenomation, irrespective of whether they were bitten by viper, cobra or krait, brought within 24 hours of the bite to Jubilee Mission Hospital, Trichur, Kerala State during the 15 months from August 2001 to October 2002 were randomized into two groups of 50 cases each, irrespective of the severity of the cases. One group received a fixed dose regime of six vials of anti-snake venom and the other 12 vials of the same. RESULTS: In the low-dose group there were five deaths giving a mortality rate of 10%, nine (18%) required dialysis and three (6%) required ventilatory support. In the high-dose group there were seven deaths giving a mortality rate of 14%, 13 (26%) required dialysis and three (6%) required ventilatory support. The average hospital stay for the low-dose group was 8.42 days while that of the high-dose group was 9.02 days. CONCLUSION: While there was no additional advantage in following a high-dose regime for snake bite cases, there was considerable financial gain by following the low-dose regime, Most of the parameters showed a beneficial trend for the low-dose group though the differences were not statistically significant.

Adolescent↗
PubMed2003

The effect of endocardial defibrillator shocks on basic atrial electrophysiology in man. Is post cardioversion atrial electrical 'remodelling' artefact?

AIMS: To determine the effect of an endocardial DC shock on the basic electrophysiology of the human atrium if delivered in sinus rhythm. METHODS AND RESULTS: A 5J endocardial R wave synchronized DC shock was delivered in 10 patients in stable sinus rhythm during ICD implantation for ventricular arrhythmias. There was no prior history of atrial fibrillation. Monophasic action potential duration (APD) and atrial effective refractory periods (AERP) were evaluated before, 1 min post DC shock, and 15 min post shock. These parameters were assessed at basic cycle lengths and at atrial paced cycle lengths of 600 ms and 400 ms at two right atrial sites; mid lateral right atrial wall (MRLA) and the right atrial appendage (RAA). There were no significant differences in APD 90, AERP or atrial refractory dispersion at any site or drive cycle length before, immediately after or 15 min after shock delivery. CONCLUSIONS: There are no significant changes in basic electrophysiological parameters following a DC shock delivered in sinus rhythm in patients with no prior history of atrial fibrillation. This suggests that atrial electrical remodelling occurs as a result of atrial fibrillation and is unrelated to shock artefact.

Artifacts↗
PubMed2003

Trial of heparin in viper bites.

AIMS OF THE STUDY: Viper bites produce hematotoxicity and coagulopathy which may be either true disseminated intravascular coagulation (DIC) or DIC-like syndrome. Role of heparin is studied in the present study of viper bite cases as use of heparin provides a rational therapy for defibrination caused by viper envenomation. METHODOLOGY: One hundred and twenty two patients with viper bite and incoagulable blood were randomised into test group and control group. Test group received heparin in addition to antisnake venom (ASV). Efficacy was assessed by monitoring bleeding time (BT), clotting time (CT), prothrombin time (PT), platelets, fibrinogen, blood urea (BU), serum creatinine, development of complications and overall outcome. RESULTS: Heparin group showed favourable outcome in all parameters studied. But many of them were not statistically significant. CONCLUSION: Heparin seems to be having a beneficial role which needs to be confirmed by larger trials and longer duration of heparin administration.

Adult↗
PubMed2002

Evidence that nitric oxide production increases gamma-amino butyric acid permeability of blood-brain barrier.

Blood-brain barrier permeability (BBB) to the inhibitory neurotransmitter gamma-amino butyric acid (GABA) was studied in rats following intraperitoneal (i.p) injections of GABA alone and in combination with L-Arginine (L-Arg). Administration of GABA (600 mg/kg body weight [b. wt.]) alone increased brain GABA concentration (33%, p < 0.01), when compared to untreated rats and administration of L-Arg (2000 mg/kg b. wt.) alone also increased GABA concentration (65%, p < 0.01) in the brain. Moreover, GABA + L-Arg treated brains showed a fourfold increase in GABA level (383.3%, p < 0.01) when compared to controls. Dose-dependent increase in nitric oxide production was observed 10 min after i.p injections of L-Arg (400, 800, 1000, and 2000 mg/kg b. wt.) and a peak nitric oxide (NO) production was observed at the dose level of 2000 mg/kg b. wt. On the other hand, administration of GABA failed to increase NO production in the brain. Rats pretreated (10 min) with a nonspecific nitric oxide synthase (NOS) inhibitor N(omega)-nitro-L-Arginine methyl ester (L-NAME, 50 mg/kg b. wt.) completely blocked the production of NO induced by L-Arg. In addition, L-NAME attenuated GABA entry into the brain after the administration of GABA alone or in combination with L-Arg. We conclude that high NO concentrations in the brain following L-Arg administration may increase the permeability of BBB to peripheral GABA.

Animals↗
PubMed2001

Enantiomeric synthesis of D- and L-cyclopentenyl nucleosides and their antiviral activity against HIV and West Nile virus.

Enantiomeric synthesis of D- and L-cyclopentenyl nucleosides and their antiviral activity against HIV and West Nile virus are described. The key intermediate (-)- and (+)-cyclopentenyl alcohols (7 and 15) were prepared from D-gamma-ribonolactone and D-ribose, respectively. Coupling of 7 with appropriately blocked purine and pyrimidine bases via the Mitsunobu reaction followed by deprotection afforded the target L-(+)-cyclopentenyl nucleosides (24-28, 31, 33, and 36). D-(-)-Cyclopentenyl nucleosides (1, 40, 43, and 52-56) were also prepared by a similar procedure for L-isomers from 15. The synthesized compounds were evaluated for their antiviral activity against two RNA viruses: HIV and West Nile virus. Among the synthesized D-(-)-nucleosides, adenine (1, neplanocin A), cytosine (55, CPE-C), and 5-fluorocytosine (56) analogues exhibited moderate to potent anti-HIV activity (EC(50) 0.1, 0.06, and 5.34 microM, respectively) with significant cytotoxicity in PBM, Vero, and CEM cells. Also, cytosine (55) and 5-fluorocytosine (56) analogues exhibited the most potent anti-West Nile virus activity (EC(50) 0.2-3.0 and 15-20 microM, respectively). Among L-(+)-nucleosides, only the cytosine (27) analogue exhibited weak anti-HIV activity (EC(50) 58.9 microM).

Animals↗
PubMed2001

Pharmacological evidence for a role of gamma-aminobutyric acid A receptor mechanism in modulating nitric oxide synthase activity in rat brain.

The role of gamma-aminobutyric acid (GABA) mechanism on the synthesis of nitric oxide (NO) has been investigated by measuring the activity of nitric oxide synthase (NOS) and the concentration of NO in rat brain 15 min after administration of anticonvulsant doses of diazepam (0.25 and 0.5 mg/kg) which is known to activate GABA A receptor for its anticonvulsant action. Diazepam enhanced both NOS activity and the concentration of NO in a dose-dependent manner. A reversal has been observed in animals treated with a convulsant dose of picrotoxin (5 mg/kg) which is known to produce convulsions by blocking GABA A receptor mechanism. These results suggest that a functional interaction occurs between GABA A receptor activity and NO synthesis in the brain.

Animals↗
PubMed2001

Calcium preventing locomotor behavioral and dental toxicities of fluoride by decreasing serum fluoride level in rats.

Spontaneous motor activity, rota-rod performance (motor co-ordination), body weight gain, food intake, activities of total cholinesterase (blood) and acetylcholinesterase (brain), and dental structure were determined in adult female rats treated with a very high dose of sodium fluoride (500 ppm in drinking water) alone and in combination with calcium carbonate (50 mg/kg body weight by oral intubation) for 60 days. The concentration of fluoride and calcium were measured in the serum of these animals. Administration of sodium fluoride with drinking water produced both behavioural and dental toxicities and not lethality in the present study. A suppression of spontaneous motor activity, a shortening of rota-rod endurance time, a decreased body weight gain and food intake, a suppression of total cholinesterase and acetylcholinesterase activities and dental lesion were observed in test animals. Serum fluoride concentration was raised markedly and that of calcium was decreased in these animals. The effects of sodium fluoride were prevented significantly when animals received calcium carbonate along with sodium fluoride. Serum fluoride content was decreased and that of calcium was restored to control level in these animals. These results indicate that calcium prevents not only fluoride-induced hypocalcemia but also the locomotor behavioral and dental toxicities of fluoride by decreasing bioavailability of fluoride.

Journal Article↗
PubMed2001

No incremental benefit of multisite atrial pacing compared with right atrial pacing in patients with drug refractory paroxysmal atrial fibrillation.

OBJECTIVE: To evaluate the incremental antifibrillatory effect of multisite atrial pacing compared with right atrial pacing in patients with drug refractory paroxysmal atrial fibrillation paced for arrhythmia prevention alone. METHODS: In 20 of these patients (mean (SD) age 64 (8) years; 14 female, six male), a single blinded randomised crossover study was performed to investigate the incremental benefit of one month of multisite atrial pacing compared with one month of right atrial pacing. Outcomes included the number of episodes of paroxysmal atrial fibrillation, their total duration obtained from pacemaker Holter memory, and quality of life using a cardiac specific questionnaire (the modified Karolinska questionnaire). RESULTS: Comparing right atrial with multisite atrial pacing, there was no significant change in either the number of paroxysmal atrial fibrillation episodes (mean (SD): right atrial pacing 77 (98) episodes v multisite pacing 52 (78) episodes, NS) or their total duration (right atrial, 4.8 (5.4) days v multisite, 6.3 (9.8) days, NS). Quality of life scores compared with baseline status were equally improved by either pacing strategy (mean percentage improvement: right atrial, 38%, p = 0.003; multisite, 44%, p = 0.003). There was no significant difference in life scores comparing the two pacing modes. CONCLUSIONS: Multisite atrial pacing has no incremental antiarrhythmic effect compared with right atrial pacing in patients paced for drug refractory paroxysmal atrial fibrillation. Quality of life is equally improved with either pacing strategy, with no differences between them.

Aged↗
PubMed2001

Importance of rate control or rate regulation for improving exercise capacity and quality of life in patients with permanent atrial fibrillation and normal left ventricular function: a randomised controlled study.

OBJECTIVE: To determine the importance of rhythm regulation or rate control in patients with permanent atrial fibrillation (AF) and normal left ventricular function. PATIENTS AND INTERVENTIONS: Thirty six patients with a mixed fast and slow ventricular response rate to their AF were randomised to either His bundle ablation (HBA) and VVIR pacemaker (HBA group) or VVI pacemaker and atrioventricular modifying drugs (Med group). Outcomes assessed at one, three, six, and 12 months included exercise duration and quality of life. RESULTS: Exercise duration significantly improved from baseline in both groups. There was no difference in outcome between the groups (Med +40% v HBA +20%, p = NS). The heart rate profile on exercise was similarly slowed in both groups compared to baseline. Quality of life significantly improved in both treatment arms for the modified Karolinska questionnaire (KQ) (Med +50% v HBA +50%, p = NS) and the Nottingham health profile (NHP) (Med +40% v HBA +20%, p = NS). However, for the individual symptom scores of each questionnaire more were improved in the Med group (KQ-Med 6 improved v HBA 4, NHP-Med 3 v HBA 1). Left ventricular function was equally preserved by both treatments during follow up. CONCLUSION: In these patients control of ventricular response rate with either HBA + VVIR pacemaker or atrioventricular modifying drugs + VVI pacemaker will lead to a significant improvement in exercise duration and quality of life. Rhythm regulation by HBA did not confer additional benefit, suggesting rate control alone is necessary for the successful symptomatic treatment of these patients in permanent AF.

Aged↗
PubMed2001

Effect of systemically administered nitric oxide donor, sodium nitroprusside on picrotoxin-induced convulsions in rats.

Nitric oxide (NO), the gaseous neurotransmitter has been reported to have an endogenous anticonvulsant property. This has prompted proposals to develop NO donors as anticonvulsant drugs. In the present study, the effect of NO donor, sodium nitroprusside (SNP) on picrotoxin (PCT)-induced convulsions was investigated. A convulsant dose of PCT (5 mg/kg) was administered 5, 10, 15 and 30 min after intraperitoneal injection of graded doses (0.7, 1.25 and 2.5 mg/kg) of SNP. SNP at doses 0.7 and 1.25 mg/kg increased dose dependently the severity of PCT-induced convulsions. But, pretreatment with the higher dose (2.5 mg/kg) of SNP was protective against PCT-induced convulsions. However, post treatment (5 and 10 min) with the same dose exacerbated convulsions and caused death of the animals. These results indicate that the vasodilator effect of SNP and an increased perfusion of PCT into brain may be responsible for the proconvulsant action of SNP. A decreased entry of PCT because of marked vasodilation and hypotension has been speculated for an inhibition of convulsions in animals pretreated with a higher dose of SNP. In conclusion, the results reveal the non-suitability of SNP to be developed as an anticonvulsant.

Animals↗
PubMed2000

Randomized controlled study investigating the effect of biatrial pacing in prevention of atrial fibrillation after coronary artery bypass grafting.

BACKGROUND: Atrial fibrillation (AF) is a common problem after CABG. Prevention with prophylactic drug therapy has had limited success, therefore alternative approaches are required. This study investigated the role of biatrial pacing compared with no pacing on AF incidence after isolated first-time CABG. METHODS AND RESULTS: During surgery, temporary pacing leads were placed in the lateral wall of the right atrium and at the roof of the left atrium in Bachmann's bundle to allow bipolar pacing and sensing at each site. After surgery, all patients were connected to an external pacemaker (Chorum ELA) that also acted as a Holter monitor. Patients were consecutively randomized to either 4 days of biatrial pacing at a base rate of 80 bpm or to no pacing (control group, base rate 30 bpm). End points included an episode of AF lasting >1 hour on pacemaker Holter, clinically detected AF, intensive care unit (ICU) and hospital stay, and postoperative complications. One hundred thirty patients were randomized. Biatrial pacing significantly reduced both monitored (13.8% versus 38.5%, P:=0.001) and clinical (10.8% versus 33.8%, P:=0.002) episodes of AF. Median ICU (19 versus 24 hours, P:=NS) and mean hospital stay (7.7+/-6.9 versus 9.7+/-10, P:=NS) did not significantly change. The number of postoperative complications was lower in the biatrial group (13 versus 35, P:=0. 001). CONCLUSIONS: Biatrial pacing after CABG significantly decreases the incidence of AF. This is associated with reduced postoperative complications and a trend toward reduced ICU and hospital stay.

Aged↗
PubMed2000

Ablate and pace for drug refractory paroxysmal atrial fibrillation. Is ablation necessary?

BACKGROUND: Atrio-ventricular junctional ablation with pacemaker insertion has been shown to improve quality of life in patients with drug refractory paroxysmal atrial fibrillation. It is unknown whether this improvement is secondary to the ablation procedure or to the pacemaker mode utilised. To investigate this we reviewed our experience of implanting a dual chamber rate responsive pacemaker with mode switching (DDDR/MS) alone on quality of life in this patient group. METHODS AND RESULTS: Over a 1-year period, 19 patients (mean age 62+/-9 years, 13 female) with drug refractory paroxysmal atrial fibrillation (mean duration of symptoms 8.7+/-7 years, failed 3.1+/-0.9 anti-arrhythmic drugs, amiodarone in 15) were recruited. Quality of life was assessed at baseline and after 1 month using a cardiac specific questionnaire, the modified Karolinska questionnaire. The mean score for all patients significantly improved by 39% at follow up (baseline 59+/-24, 1 month 36+/-24, P=0.001). Individually 15 patients (79%) had an improvement in their score, whilst for 13 patients (68%) their symptoms were sufficiently improved after pacing that ablation was not required. The benefit was maintained to a mean follow up of 12+/-5 months (score 31+/-20, P<0.001). Six patients remained symptomatic after pacing and requested further treatment. Benefit was unrelated to symptoms at baseline or the number and total duration of paroxysmal atrial fibrillation episodes recorded on pacemaker Holter. CONCLUSIONS: Patients with drug refractory paroxysmal atrial fibrillation, DDDR/MS pacing alone can improve quality of life without concurrent atrio-ventricular junctional ablation in a significant proportion of patients.

Aged↗
PubMed2000

A role of nitric oxide as an inhibitor of gamma-aminobutyric acid transaminase in rat brain.

The present study has been aimed to investigate the effect of nitric oxide (NO) on the concentration of gamma-aminobutyric acid (GABA) in rat brain. The concentrations of GABA and glutamate and the activities of glutamic acid decarboxylase (GAD) and gamma-aminobutyric acid transaminase (GABA-T) were determined in groups of animals 5 and 30 min after intraperitoneal injection of a NO-increasing dose (1,000 mg/kg) of its precursor, L-arginine and a dose (50 mg/kg) of N-nitro-L-arginine methyl ester (L-NAME) that inhibits NO synthesis from L-arginine. L-arginine-induced elevation of NO concentration was accompanied by an increased concentration of GABA in the brain. GABA-T activity was inhibited in these animals. NO-decreasing action of L-NAME coincided with a reduction in the concentration of GABA and an enhancement of GABA-T activity. Both L-arginine and L-NAME did not alter the activity of GAD and the concentration of glutamate. An interpretation of these data suggests that NO has a GABA-T-inhibiting role in the brain.

4-Aminobutyrate Transaminase↗
PubMed2000

Does atrial overdrive pacing prevent paroxysmal atrial fibrillation in paced patients?

The role of atrial overdrive pacing for the suppression of paroxysmal atrial fibrillation remains unclear. To investigate this we have performed a randomised study evaluating the role of an increased atrial base rate in suppressing this arrhythmia in patients implanted with a permanent pacemaker (Chorum ELA) for sick sinus syndrome with previous documented paroxysmal atrial fibrillation. Twenty-seven patients (mean age, 69; 15 female) were randomised to two 3-month single-blinded crossover periods of DDDR pacing. The pacemaker was set with a base rate of 60 bpm (normal) during one period and at 10 bpm (overdrive) above the average heart rate during the other, mean (S.D.) 75+/-7 beats/min (range, 70-96). The fallback algorithm of the pacemaker was activated to record the number and duration of paroxysmal atrial fibrillation episodes. During the overdrive period there was a significant increase in the total duration of atrial pacing (normal 60+/-26% vs. overdrive 72+/-28%, P<0.001). However there was no significant difference in the number of paroxysmal atrial fibrillation episodes (normal 43+/-109 vs. overdrive 43+/-106, P=ns), or their total duration (normal 42+/-108 h vs. overdrive 99+/-254 h, P=ns). In conclusion, atrial overdrive pacing, achieved by increasing the atrial base rate, has no incremental benefit in the suppression of paroxysmal atrial fibrillation when compared to rate responsive pacing with a base rate of 60 bpm.

Aged↗