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Biomedical subjects

S Mittal

Publications and source records attributed to S Mittal.

At least 55 records · Page 3Linked to original sources
PubMed1999

Comparison of a novel rectilinear biphasic waveform with a damped sine wave monophasic waveform for transthoracic ventricular defibrillation. ZOLL Investigators.

OBJECTIVES: We compared the efficacy of a novel rectilinear biphasic waveform, consisting of a constant current first phase, with a damped sine wave monophasic waveform during transthoracic defibrillation. BACKGROUND: Multiple studies have shown that for endocardial defibrillation, biphasic waveforms have a greater efficacy than monophasic waveforms. More recently, a 130-J truncated exponential biphasic waveform was shown to have equivalent efficacy to a 200-J damped sine wave monophasic waveform for transthoracic ventricular defibrillation. However, the optimal type of biphasic waveform is unknown. METHODS: In this prospective, randomized, multicenter trial, 184 patients who underwent ventricular defibrillation were randomized to receive a 200-J damped sine wave monophasic or 120-J rectilinear biphasic shock. RESULTS: First-shock efficacy of the biphasic waveform was significantly greater than that of the monophasic waveform (99% vs. 93%, p = 0.05) and was achieved with nearly 60% less delivered current (14 +/- 1 vs. 33 +/- 7 A, p < 0.0001). Although the efficacy of the biphasic and monophasic waveforms was comparable in patients with an impedance < 70 ohms (100% [biphasic] vs. 95% [monophasic], p = NS), the biphasic waveform was significantly more effective in patients with an impedance > or = 70 ohms (99% [biphasic] vs. 86% [monophasic], p = 0.02). CONCLUSIONS: This study demonstrates a superior efficacy of rectilinear biphasic shocks as compared with monophasic shocks for transthoracic ventricular defibrillation, particularly in patients with a high transthoracic impedance. More important, biphasic shocks defibrillated with nearly 60% less current. The combination of increased efficacy and decreased current requirements suggests that biphasic shocks as compared with monophasic shocks are advantageous for transthoracic ventricular defibrillation.

Aged↗
PubMed1999

Induction of neurally mediated syncope with adenosine.

BACKGROUND: Tilt testing is used to establish the diagnosis of neurally mediated syncope. However, applicability of the tilt test is limited by test sensitivity and length of time required to perform the test. We hypothesized that adenosine could facilitate the induction of neurally mediated syncope through its sympathomimetic effects and therefore could be used as an alternative to routine tilt testing. METHODS AND RESULTS: In protocol 1, the yield of adenosine tilt testing (12 mg while upright, followed by 60 degrees tilt for 5 minutes) and a 15-minute isoproterenol tilt test were compared in 84 patients with a negative 30-minute drug-free tilt test. In protocol 2, 100 patients underwent an initial adenosine tilt test followed by our routine tilt test (30-minute drug-free tilt followed by a 15-minute isoproterenol tilt). Six additional control patients underwent microneurography of the peroneal nerve to compare the sympathomimetic effects during bolus administration of adenosine and continuous infusion of isoproterenol. In protocol 1, the yields of adenosine (8 of 84, 10%) and isoproterenol (7 of 84, 8%) tilt testing were comparable (P=NS). In protocol 2, the yields of adenosine (19 of 100, 19%) and routine (22 of 100, 22%) tilt testing were also comparable (P=NS). Although the yield of adenosine tilt testing was comparable in both protocols, patients with a negative adenosine tilt test but a positive routine tilt test usually required isoproterenol to elicit the positive response. Microneurography confirmed discordant sympathetic activation after adenosine and isoproterenol administration. CONCLUSIONS: Adenosine is effective for the induction of neurally mediated syncope, with a diagnostic yield comparable to routine tilt testing. However, the discordant results obtained with adenosine and the isoproterenol phase of routine tilt testing suggest that adenosine and isoproterenol tilt testing may have complementary roles in eliciting a positive response. Therefore, a tilt protocol that uses an initial adenosine tilt followed, if necessary, by an isoproterenol tilt would be expected to increase the overall yield and reduce the duration of tilt testing.

Adenosine↗
PubMed1999

A combined laparoscopic-endoscopic method of assessment to prevent the complications of short esophagus.

As antireflux surgery has been used increasingly for gastroesophageal reflux disease (GERD), a need has arisen for an accurate method to assess esophageal length. There are a number of preoperative tests that can help surgeons to establish the presence of a short esophagus, but intraoperative assessment after esophageal mobilization is the standard method. In this era of laparoscopic surgery, the surgeon mobilizes the esophagus extensively from the abdomen and then determines if mobilization is sufficient. We report an intraoperative technique that combines laparoscopic with endoscopic methods to determine the position of the gastroesophageal junction. Because two physicians are required, there is additional operating room time, resulting in increased costs. However, these costs are offset by the assurance that the complications of the short esophagus can be avoided. With experience, modifications were made, resulting in the technique described herein.

Endoscopy↗
PubMed1999

Etiology and outcome of chronic renal failure in Indian children.

A prospective analysis of all new pediatric cases of chronic renal failure (CRF) was performed at our hospital over a 1-year period. The diagnosis of CRF was based on serum creatinine >2 mg/dl with supportive clinical, laboratory, and radiological findings. There were a total of 48 patients with CRF with a median age of 13 years (range 10 days to 16 years). The causes of CRF included glomerulonephritis (37.5%), obstruction and interstitial (52%), hereditary (6.3%), and undetermined (4.2%). Patients were symptomatic for a mean of 33.2 months (range 10 days to 11 years) at presentation. Eight patients (16.7%) had acute reversible deterioration of renal function at presentation. This was due to accelerated hypertension in 2, infection in 3, volume depletion in 2, and nonsteroidal antiinflammatory drugs in 1 patient. At presentation, 22 (46%) children had mild to moderate renal failure and 26 (54%) had end-stage renal disease. Twenty-one children (43. 7%) had associated illness at presentation. Mean follow-up was 22.9 weeks (range 2-126 weeks). At the end of the study period, 10 (21%) patients were on conservative treatment, 7 (14.6%) on maintenance dialysis, 8 (16.7%) patients had functioning allografts, 4 (8.3%) patients had died, and 19 (39.6%) opted against further therapy. We conclude that CRF in Indian children carries a poor prognosis due to late referral and the limited availability and high cost of renal replacement therapy.

Adolescent↗
PubMed1999

Ultrasound guided aspiration of endometrioma--a new therapeutic modality to improve reproductive outcome.

OBJECTIVE: To evaluate the therapeutic efficacy and reproductive outcome following ultrasound guided aspiration (UGA) of endometrioma in infertile patients. METHOD: This is a prospective non-randomized clinical report of UGA in 22 infertile patients with endometrioma. The aspiration of endometriotic cysts was carried out transvaginally in nine and transabdominally in 13 patients. Following aspiration intranasal buserilin was given to eight and danazol to 14 patients. In the case of recurrence a reaspiration was done. Patients were allowed to conceive following medical therapy. Recurrence of endometrioma and conception rate was recorded and correlated with endometrioma size and volume aspirated. RESULT: A total of 47 aspirations were done. There were no procedure related complications. Reaspiration was required in six patients and one was operated (total recurrence 7/22--31.8%). During a mean follow-up of 20+/-8.4 months nine patients (40.9%) conceived and eight have already delivered at term. The recurrence risk and the conception rate was not affected by the cyst size or volume aspirated. CONCLUSION: UGA of endometrioma can be an effective and safe alternative therapeutic procedure in infertile patients with endometrioma to improve their reproductive outcome.

Adult↗
PubMed1999

Long-term outcome of patients with unexplained syncope treated with an electrophysiologic-guided approach in the implantable cardioverter-defibrillator era.

OBJECTIVES: We evaluated the long-term outcome of patients with coronary artery disease and unexplained syncope who were treated with an electrophysiologic (EP)-guided approach. BACKGROUND: Electrophysiologic studies are frequently performed to evaluate unexplained syncope in patients with coronary artery disease. Patients with this profile who have inducible ventricular tachycardia are considered at high risk for sudden death and increased overall mortality, and therefore are often treated with an implantable cardioverter-defibrillator (ICD). The impact of this EP-guided strategy is unknown because there are no data comparing the long-term outcome of ICD recipients with that of noninducible patients. METHODS: We evaluated 67 consecutive patients with coronary artery disease and unexplained syncope. All patients were treated with an EP-guided approach that included ICD implantation in patients with inducible ventricular tachycardia. RESULTS: Electrophysiologic testing suggested a plausible diagnosis in 32 (48%) of these patients. Inducible monomorphic ventricular tachycardia was the most common abnormality. Despite frequent appropriate therapy with ICDs, the total mortality for patients with inducible monomorphic ventricular tachycardia was significantly higher than for noninducible patients. The respective one- and two-year survival rates were 94% and 84% in noninducible patients and 77% and 45% in inducible patients (p = 0.02). CONCLUSIONS: Electrophysiologic testing suggests an etiology for unexplained syncope in approximately 50% of patients and risk stratifies these patients with regard to long-term outcome. Patients who receive an ICD for the management of inducible ventricular tachycardia have a high incidence of spontaneous ventricular arrhythmias requiring ICD therapy. However, despite ICD implantation and frequent appropriate delivery of ICD therapies, patients with inducible ventricular tachycardia have a significantly worse prognosis than do those who are noninducible.

Aged↗
PubMed1999

Mononuclear cell-modulation of granulosa cell steroidogenesis in rat: influence of ovarian cycle.

The mononuclear cells exert a paracrine influence on the ovarian function, including steroidogenesis. This study examines the ability of the conditioned medium from the cultures of splenic mononuclear cells, obtained during various phases of the ovarian cycle, on progesterone accumulation by the granulosa cells in the culture medium. Female Wistar rats, aged twenty-five days, were made pseudopregnant by an injection of pregnant mare's serum gonadotropin. The splenic mononuclear cells were isolated at follicular phase, early luteal phase, mid luteal phase and late luteal phase and cultured for 48 h. The ammonium sulphate precipitated fraction of the conditioned medium was added to the granulosa cells obtained from immature rats treated with diethylstillboestrol. The granulosa cells were cultured for 48 h, and the progesterone accumulated in the medium was assayed. The conditioned medium from the cultures of the mononuclear cells obtained during follicular phase and late luteal phase inhibited FSH-induced progesterone secretion, whereas conditioned medium obtained from mid luteal phase mononuclear cells enhanced the effect of FSH. The stimulatory effect of db-cAMP on progesterone accumulation in the culture medium is inhibited by conditioned medium obtained from all the phases of the ovarian cycle. This study demonstrates a cyclicity in the behaviour of the splenic mononuclear cells on ovarian steroidogenesis, suggesting a bi-directional paracrine and/or endocrine relationship between ovary and the mononuclear cells.

Animals↗
PubMed1999

Catecholamine facilitated reentrant ventricular tachycardia: uncoupling of adenosine's antiadrenergic effects.

INTRODUCTION: Adenosine has no direct electrophysiologic function in ventricular tissue, but in the presence of cyclic adenosine monophosphate (cAMP), stimulation exerts a potent antiadrenergic effect. This effect has been exploited in the recognition and treatment of ventricular tachycardia (VT) due to cAMP-mediated triggered activity and automaticity, which are respectively terminated and suppressed by adenosine. However, the effects of adenosine on catecholamine-facilitated reentrant VT are unknown. A pivotal issue is whether termination of VT with adenosine is mechanism specific, or whether it represents a nonspecific antiadrenergic effect. The purpose of this study, therefore, was to define the effects of adenosine in a well-characterized group of patients with catecholamine-facilitated reentrant VT. METHODS AND RESULTS: Fourteen patients with catecholamine-facilitated reentry were studied. In the 12 patients with structural heart disease (including two with arrhythmogenic right ventricular dysplasia), adenosine (260 to 550 microg/kg) failed to slow or terminate VT. Two patients without structural heart disease had intrafascicular tachycardia confined to the left posterior fascicle, a calcium-dependent, verapamil-sensitive arrhythmia. In the absence of isoproterenol, verapamil terminated VT but adenosine did not. However, when isoproterenol was subsequently required for facilitation of tachycardia, adenosine terminated VT in both patients. CONCLUSION: Adenosine has no antiadrenergic (antiarrhythmic) effect in patients with catecholamine-facilitated VT due to structural heart disease. Patients with verapamil-sensitive, left posterior intrafascicular reentry have an unusual dual response to adenosine. In the unstimulated state, adenosine has no effect on basal inward calcium current and, therefore, no effect on VT. However, when induction of VT requires amplification of the inward calcium current through stimulation of cAMP, adenosine sensitivity of VT becomes manifest. These results indicate that with few exceptions, termination of VT with adenosine is strongly suggestive of a cAMP-mediated triggered mechanism rather than reentry.

Adenosine↗
PubMed1999

Differential effects of adenosine on focal and macroreentrant atrial tachycardia.

INTRODUCTION: The effects of adenosine on atrial tachycardia (AT) remain controversial, and the mechanistic implications of adenosine termination have not been fully established. The purpose of this study was to elucidate the differential effects of adenosine on focal and macroreentrant AT and describe the characteristics of adenosine-sensitive AT. METHODS AND RESULTS: Thirty patients received adenosine during AT. Tachycardia origins were identified as focal or macroreentrant during invasive electrophysiologic studies. Responses to adenosine were analyzed and characterized as tachycardia termination, transient suppression, or no effect. Electrophysiologic studies demonstrated a focal origin of tachycardia in 17 patients. Adenosine terminated focal tachycardias in 14 patients (dose 7.3 +/- 4.0 mg) and transiently suppressed the arrhythmias in three others (dose 10.0 +/- 6.9 mg). A macroreentrant mechanism was demonstrated in 13 patients; adenosine terminated only one of these tachycardias and had no effect on the remaining 12 patients (dose 10.2 +/- 2.9 mg). Four classes of adenosine-sensitive AT were identified. Class I consisted of nine patients with tachycardia arising from the crista terminalis; these tachycardias also terminated with verapamil (4/4). Class II consisted of four patients with repetitive monomorphic AT arising from diverse sites in the right atrium; these either slowed or terminated in response to verapamil (2/2). Class III consisted of the three patients with transient suppression and demonstrated electropharmacologic characteristics consistent with an automatic mechanism, including insensitivity to verapamil (2/2). In the one patient with macroreentrant AT that was comprised of decremental atrial tissue, adenosine terminated tachycardia in a zone of decremental slow conduction (Class IV); this tachycardia slowed with verapamil. CONCLUSIONS: Adenosine-sensitive AT is usually focal in origin and arises either from the region of the crista terminalis (inclusive of the sinus node) or from diverse atrial sites with an incessant nonsustained repetitive pattern. Although most forms of macroreentrant AT are insensitive to adenosine, rarely macroreentrant AT with zones of decremental slow conduction can demonstrate adenosine sensitivity.

Adenosine↗
PubMed1999

Cytological study of serous effusions with the aid of tumour markers.

Clinicocytological evaluation with the help of tumour markers was done in 25 cases presenting with serous effusions. The main aim was to differentiate between reactive mesothelial cells and malignant cells, type the tumour cells in effusions with the aid of tumour markers--carcino-embryonic antigen (CEA), epithelial membrane antigen (EMA), cytokeratin and vimentin. It was observed that immunocytochemistry has complemented conventional cytology in diagnosis of carcinoma specially in cases labelled as suspicious of malignancy. EMA was found to be the most reliable epithelial marker and very useful in differentiating carcinoma cells from reactive mesothelial cells.

Abdominal Neoplasms↗
PubMed1998

Mammary coronary artery anastomosis without cardiopulmonary bypass through minithoracotomy: one year clinical experience.

OBJECTIVE: The recent concept of minimally invasive coronary artery surgery in selected patients has dramatically affected surgical management of coronary artery disease. We explored the possibility of coronary artery bypass grafting of anterior coronary arteries with in situ internal mammary artery through a limited anterior thoracotomy on beating heart. METHOD: Minithoracotomy and direct coronary artery surgery without cardiopulmonary bypass (CPB) was attempted in 116 patients. The procedure was completed in 108 cases while in eight cases minithoracotomy was converted to mid sternotomy. In 107 cases, left internal mammary artery (LIMA) to left anterior descending (LAD) coronary artery anastomosis was done through left anterior minithoracotomy and in one case LIMA to LAD and right internal mammary artery (RIMA) to right coronary artery (RCA) anastomosis was done through bilateral minithoracotomy. Left anterior minithoracotomy through 4th intercostal space and right anterior minithoracotomy through 5th intercostal space was used for left and right internal mammary artery dissection respectively. With this approach 4-8 cm length of mammary artery was easily dissected. Mammary coronary artery anastomosis were performed on a beating heart without CPB through window pericardiotomy. Two patients also underwent left carotid endarterectomy along with LIMA to LAD anastomosis. In two patients complementary percutaneous transluminal coronary angioplasty (PTCA) to circumflex artery was done 5 days after minithoracotomy and LIMA to LAD anastomosis. RESULTS: Forty-two patients were extubated in the operating room and 66 in the intensive care unit 2-10 h after surgery. Blood transfusion was used in one case who was reexplored for postoperative bleeding due to a displaced hemoclip from the internal mammary artery branch. None of these patients required inotropic support. Postoperative predischarge check angiogram in 53 cases revealed adequate mammary coronary flow in 51 cases, the remaining two had anastomotic problems, one was subjected to PTCA and the other for redo coronary bypass grafting through mid sternotomy. Doppler flow assessment of anastomosis was done in 102 cases, of which two showed problems which was confirmed on check angiography. One-hundred and six patients are in our regular follow-up (mean follow-up 10+/-1.5 months), 98 of them are in functional class I. CONCLUSION: In our experience mammary coronary artery anastomosis without CPB through minithoracotomy is a safe, simple and minimally invasive procedure. Favorable cost/benefit ratio, has been achieved due to no early/late mortality and minimal early morbidity. Postoperative check angiogram and Doppler flow study revealed excellent mid term results.

Cardiopulmonary Bypass↗
PubMed1998

Posterior scleritis: clinical profile and imaging characteristics.

Posterior scleritis is relatively uncommon and is often misdiagnosed due to its protean manifestations. We report eight cases of posterior scleritis to analyse the clinical profile, ultrasonographic and computed tomography (CT) scan features of this rare disorder. Fundus findings included serous retinal detachment, choroidal folds, retinal folds, subretinal mass, choroidal detachment, disc edema, and macular edema. There was associated anterior scleritis and anterior uveitis in the majority of the cases. In all cases ultrasound with or without CT scan confirmed the clinical diagnosis. All patients responded to systemic steroids except one who required immunosuppressive therapy. This paper describes the clinical profile of a series of posterior scleritis cases highlighting varied clinical presentation, and the role of ultrasound and CT scan findings in the diagnosis.

Adolescent↗
PubMed1998

Evaluation of endothelial function in postkeratoplasty eyes.

BACKGROUND AND OBJECTIVE: To evaluate corneal endothelium function in postkeratoplasty eyes. PATIENTS AND METHODS: Endothelial function was assessed in 23 clear corneal grafts. After a measurable corneal edema was induced by soft contact lens wear, serial pachometric readings were taken for 3 hours to arrive at the percentage recovery per hour (PRPH) index. RESULTS: The assessed PRPH values of the clear corneal grafts ranged from 24.6% to 73.0%, with a mean value of 51.8% +/- 12.2%. Of the six corneal grafts that demonstrated an initial PRPH value of less than 47.5%, four became edematous within 6 months of follow-up. CONCLUSIONS: Assessed PRPH, as an in vivo-measured index of endothelial function, is a valuable method for monitoring endothelial function in postkeratoplasty eyes. The low PRPH index identifies eyes at risk of spontaneous nonimmunologic failures.

Corneal Edema↗
PubMed1998

Primary amenorrhoea: analysis of 48 cases.

The clinical analysis of 48 patients of primary amenorrhoea seen at All India Institute of Medical Sciences, New Delhi for a period of 3 years, was performed. Twenty-six patients (54.2%) had muellerian anomalies, 11 (22.9%) had hypogonadotropic hypogonadism, 8 (16.6%) had hypergonadotropic hypogonadism and 3 (6.3%) had genital tuberculosis. The study highlights the role of transabdominal sonography in the work up of these cases. It suggests the reproductive potential of these cases by visualising the genital organs and makes laparoscopy and intravenous pyelography obsolete and selects the cases who deserve to be further investigated.

Adolescent↗