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Biomedical subjects

G Manoharan

Publications and source records attributed to G Manoharan.

13 recordsLinked to original sources
PubMed2006

Head to head comparison of N-terminal pro-B-type natriuretic peptide and B-type natriuretic peptide in patients with/without left ventricular systolic dysfunction.

BACKGROUND: Human pro-B-type natriuretic peptide is cleaved into the active B-type natriuretic peptide (BNP) and the inactive fragment NT-proBNP. It is unclear if, similar to BNP, NT-proBNP can be used as a marker of impaired left ventricular (LV) ejection fraction (EF). This study evaluated the analytical performance of both assays to detect LV systolic dysfunction. METHODS: In 72 patients with various degrees of left ventricular systolic dysfunction (LVSD), blood analysis for BNP and NT-proBNP was performed prior to cardiac catheterization, using a point-of-care analyzer (Biosite) and a fully automated laboratory analyzer (Roche-Elecsys), respectively. The within-run and between-run imprecision for BNP and NT-proBNP was calculated. RESULTS: Both markers were able to detect impaired LV EF with the largest area under the receiver-operating-characteristic curve for NT-proBNP (NT-proBNP: 0.851 (0.747-0.924); BNP: 0.803 (0.692-0.887) 95% confidence interval; P = 0.07). A significant correlation was observed between BNP and NT-proBNP (r = 0.9; P < 0.0001). Estimating the within-run imprecision, the coefficient of variance for BNP was 3.14% (n = 20, mean 316 ng/L) to 3.32% (n = 20, mean 820 ng/L) and for NT-proBNP 0.9% (n = 20, mean 4390.8 ng/L) to 1.4% (n = 20, mean 225 ng/L). The between-run imprecision for NT-proBNP ranged between 2.1% (n = 20, mean 224.6 ng/L) and 2% (n = 20, mean 4391 ng/L). Optimal discriminator values for BNP and NT-proBNP were 139 ng/L and 358 ng/L, respectively. However, adjusting the BNP cut-off value to 54 ng/L improved the negative predictive value and sensitivity of the assay. CONCLUSION: Similar to BNP, NT-proBNP is a promising marker in identifying LVSD. Although both assays are reliable and have good analytical performance, their diagnostic cut-off value is dynamic and population-dependent. The slightly wider detection range and the more stable structure of NT-proBNP compared to the BNP assay suggest that NT-proBNP could play an additional role in the evaluation of patients with LV systolic dysfunction.

Adult↗
PubMed2003

Transvenous cardioversion--a novel asymmetric rectangular biphasic waveform from a radiofrequency defibrillator compared with conventional waveforms in atrial fibrillation.

BACKGROUND: We investigated a novel device that delivered biphasic and monophasic shocks without tilt, in transvenous cardioversion of atrial fibrillation (AF). The device contains a radiofrequency (RF) transmitting primary, a 15mm air gap and a passive secondary unit that produces the required direct current waveform. METHODS: The device was assessed in 10 anaesthetised and ventilated sheep (65 +/- SD 12kg). Defibrillation leads were positioned in the distal coronary sinus and the lateral right atrium. The novel RF defibrillator was assessed using rectangular monophasic or biphasic pulses and compared to conventional (C) tilted waveforms (Ventritex HVS-02). During AF placebo shocks were delivered to a 50 Omega dummy load. Sustained AF was induced by rapid atrial pacing and 5 attempts at cardioversion were made for each waveform. Success was defined as reversion to sinus rhythm within 5 beats of shock delivery. RESULTS: No arrhythmic complications were observed for the 400 shocks delivered. CONCLUSION: A reduction in phase 2 voltage does not affect the efficacy of rectangular waveforms but does facilitate energy reduction. Asymmetric rectangular biphasic waveforms with phase 2 voltage at 50% of phase 1 are more efficacious than equivalent voltage conventional waveforms for transvenous cardioversion of AF. The novel defibrillator is safe and effective. Design modifications will enable this device to be used as an implantable defibrillator with an external RF power source.

Animals↗
PubMed2003

Body surface mapping improves early diagnosis of acute myocardial infarction in patients with chest pain and left bundle branch block.

OBJECTIVE: To test prospectively depolarisation and repolarisation body surface maps (BSMs) for mirror image reversal, which is less susceptible to artefact, in patients with acute ischaemic-type chest pain, and to compare these BSM criteria with previously published 12 lead ECG criteria. METHODS: An 80 lead portable BSM system was used to map patients presenting with acute ischaemic-type chest pain and a 12 lead ECG with left bundle branch block (LBBB). Acute myocardial infarction (AMI) was defined by serial cardiac enzymes. Each 12 lead ECG was assessed by the criteria of Sgarbossa et al and Hands et al for diagnosis of AMI. Depolarisation and repolarisation BSMs were assessed for loss of mirror image reversal of QRS with ST-T isointegral map patterns and a change in vector angle from QRS to ST-T outside 180+/-15 degrees -findings typically seen in LBBB with AMI. RESULTS: Of 56 patients with chest pain and LBBB, 18 had enzymatically confirmed AMI. Patients with loss of BSM image reversal were significantly more likely to have AMI (odds ratio 4.9, 95% confidence interval 1.5 to 16.4, p = 0.007). Loss of BSM image reversal was significantly more sensitive (67%) for AMI than either 12 lead ECG method (17%, 33%) albeit with some loss in specificity (BSM 71%, 12 lead ECG 87%, 97%). Patients with AMI compared with those without AMI had a greater mean change in vector angle outside the normal range (180+/-15 degrees ), particularly between QRS isointegral and ST60 isopotential (the potential 60 ms after the J point at each electrode site) BSMs (19 degrees v 9 degrees, p = 0.038). Loss of image reversal and QRS-ST60 vector change outside 180+/-15 degrees had 61% sensitivity and 82% specificity for AMI (odds ratio 7.0, 95% confidence interval 2.0 to 24.4, p = 0.001). CONCLUSIONS: BSM compared with the 12 lead ECG improved the early diagnosis of AMI in the presence of LBBB.

Adult↗
PubMed2002

Syncopal episodes in a young amateur body builder.

A 36 year old male weight training enthusiast suffered several syncopal episodes. An electrocardiogram confirmed atrial fibrillation with normal ventricular response. The patient admitted to taking anabolic steroids and bromocriptine. The atrial fibrillation was considered to be due to bromocriptine misuse.

Adult↗
PubMed1999

The therapeutic use of glycoprotein IIb/IIIa inhibitors in acute coronary syndromes.

Acute coronary syndrome (ACS) embraces the clinical diagnoses of unstable angina and non-Q-wave myocardial infarction (NON-Q-MI). Conventional treatment for these conditions with aspirin, heparin and other anti-anginal drugs has its limitations. Treatment of acute symptoms with lytic therapy has not been beneficial. A large proportion of patients in this high-risk group will eventually need revascularisation due to ongoing symptoms. Platelet aggregation plays a crucial role in the pathogenesis of ACS and ischaemic complications of coronary intervention. The glycoprotein (GP) IIb/IIIa receptor, which belongs to a family of surface receptors called integrins, is the final step in this pathway. This has led to the development and use of GP IIb/IIIa inhibitors as potential therapeutic agents. Inhibitors developed so far include abciximab, a chimeric monoclonal antibody, and more recently, novel synthetic intravenous and orally administered competitive integrin blocking agents. To date, abciximab, tirofiban and eptifibatide are commercially available for clinical use. Completed clinical trials have looked at these agents as a primary treatment and as an adjunct to intervention for ACS; they have shown improvement over existing treatments, with reductions in the incidence of death, myocardial infarction (MI), refractory ischaemia and need for urgent revascularisation. Risk of bleeding and thrombocytopenia is low, and appears to be dose related and associated with concomitant treatment with high dose heparin. Cost benefit has been proven.

Journal Article↗
PubMed1991

Topical phenytoin in diabetic foot ulcers.

OBJECTIVE: The efficacy of topical phenytoin in the treatment of diabetic foot ulcers was evaluated in a controlled inpatient study. RESEARCH DESIGN AND METHODS: Fifty patients were treated with topical phenytoin, and 50 patients matched for age, sex, and ulcer areas, depth, chronicity, and infection were dressed with dry sterile occlusive dressing. RESULTS: Both groups improved, but the ulcers treated with topical phenytoin healed more rapidly. Mean time to complete healing was 21 days with phenytoin and 45 days with control. The differences seen were statistically significant (P less than 0.05) via the chi 2 test. CONCLUSIONS: Phenytoin appears to be useful as a topical agent in promoting the healing of diabetic foot ulcers.

Adult↗
PubMedDate not supplied

An unusual cause of small bowel obstruction. A case report.

A patient presented with recurrent episodes of colicky abdominal pain, nausea and vomiting, precise cause of which could not be established on evaluation. Exploratory laparotomy revealed internal herniation of proximal small bowel loops into the mesentericoparietal fossa of Waldeyer. There was a successful surgical outcome.

Adult↗
PubMedDate not supplied

Omental plug closure of large duodenal defects--an experimental study.

This study was conducted to evaluate the efficacy of omental plugging in the management of large duodenal defects and analyse the serial histopathological changes occurring in the omental plug and the edges of the defect until healing occurred as evidenced by complete mucosal cover. The study was conducted in 12 dogs. Through a laparotomy wound a 20 mm diameter defect was created in the first part of the duodenum. The abdomen was closed, leaving the defect open, for a period of three hours to allow peritonitis to set in. Subsequently the abdomen was reopened and the perforation was plugged with omentum pulled into the duodenal lumen and fixed to the edges. They were randomly sacrificed two at a time on the first week, second week, fourth week, sixth week and eight week post operatively. The morphology of the perforation site, adequacy of the duodenal lumen, and the histological picture at each stage were studied. There was no morbidity except in one dog which showed signs of high intestinal obstruction that resolved after conservative management. There was one mortality due to sepsis unrelated to the procedure. The omentum was firmly adherent and there was no evidence of leak from the site of closure. The omental plug underwent inflammation, necrotic changes, granulation, reduction in size and fibrosis. The defects decreased rapidly in size and healing was complete at eight weeks with the mucosa taking a normal histological appearance. None of the dogs exhibited luminal obstruction on autopsy. This study reaffirms the reliability of the omental plug in safely occluding large duodenal defects and producing healing through a process of inflammation, granulation, vascularisation and fibrosis eventually providing a normal duodenal mucosal cover to the perforation site.

Animals↗