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Biomedical subjects

R Goyal

Publications and source records attributed to R Goyal.

At least 109 records · Page 6Linked to original sources
PubMed1996

Comparison of the ages of tachycardia onset in patients with atrioventricular nodal reentrant tachycardia and accessory pathway-mediated tachycardia.

Atrioventricular nodal reentrant tachycardia and accessory pathway-mediated tachycardia may have different ages of tachycardia onset. Symptom onset data were obtained in 519 patients (atrioventricular nodal reentrant tachycardia, 231, accessory pathway-mediated tachycardia, 288). The mean age of the patients at the time of evaluation was 47 +/- 17 years (atrioventricular nodal reentrant tachycardia) and 37 +/- 15 years (accessory pathway-mediated tachycardia). The mean age of symptom onset was 32 +/- 18 years for atrioventricular nodal reentrant tachycardia and 23 +/- 14 years for accessory pathway-mediated tachycardia. A significantly greater proportion of patients with atrioventricular nodal reentrant tachycardia had the initial onset of symptoms after the age of 20 years (atrioventricular nodal reentrant tachycardia, 67% vs accessory pathway-mediated tachycardia, 41%, p < 0.001). In summary, there is a different mean age of symptom onset for patients with atrioventricular nodal reentrant tachycardia and accessory pathway-mediated tachycardia.

Adult↗
PubMed1996

Evaluation and extraction of the Accufix atrial J lead.

The Accufix (Telectronics Pacing Systems, Englewood, Colo.) atrial active fixation pacemaker lead has a preformed J stiff retention wire that can fracture and erode through the atrium. We screened 85 patients with digital fluoroscopy and detected 18 (21%) lead fractures. Fourteen (16%) leads were successfully extracted by percutaneous techniques. The mean time for extraction and placement of a new atrial lead was 109 +/- 53 min, and a lead > 1 year old but not in the presence of a fracture was associated with a significantly longer extraction time. There were two extraction complications. One patient had a fever following the extraction, and one patient had a focal sensory deficit 1 week after the extraction probably caused by a paradoxical embolus. Standard percutaneous extraction tools can be used for successful and safe removal of a fractured Accufix lead.

Aged↗
PubMed1996

Use of isoproterenol during programmed ventricular stimulation in patients with coronary artery disease and nonsustained ventricular tachycardia.

Twenty-three consecutive patients (20 men and 3 women) with coronary artery disease and nonsustained ventricular tachycardia (VT) in whom sustained VT was not inducible in a baseline electrophysiology test underwent repeated testing during isoproterenol infusion to determine the inducibility of sustained monomorphic VT. After the baseline study, each patient received a 2 to 4 microgram/min infusion of isoproterenol (mean 2.5 +/- 0.8 microgram/min). The sinus cycle length shortened by a mean of 29% +/- 9% and programmed stimulation was repeated. Nineteen patients had no inducible sustained, monomorphic VT, two patients had only inducible nonsustained VT, and two patients had ventricular fibrillation. Patients were followed up for 10 to 20 months (mean 14.4 +/- 2.9 months) and had no syncope, sustained monomorphic VT, or sudden death. Isoproterenol infusion during programmed stimulation in patients with coronary heart disease and nonsustained VT does not facilitate the induction of sustained monomorphic VT.

Aged↗
PubMed1996

Visual function after laser hyperthermia and chemotherapy for macular retinoblastoma.

PURPOSE: To determine whether treatment of macular retinoblastoma with chemotherapy and laser hyperthermia can lead to satisfactory visual acuity. METHODS: A child with unilateral macular retinoblastoma was treated with chemotherapy and laser hyperthermia. Visual function was assessed one year after treatment. RESULTS: At age 25 months, the patient had normal visual behavior and a normal spatial-sweep visual-evoked potential. CONCLUSION: Treatment of macular retinoblastoma with chemotherapy and laser hyperthermia may enable recovery of satisfactory visual acuity.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Slow pathway ablation in patients with documented but noninducible paroxysmal supraventricular tachycardia.

OBJECTIVES: The purpose of this study was to assess the clinical efficacy of radiofrequency ablation of the slow pathway in patients with documented but noninducible paroxysmal supraventricular tachycardia (PSVT) who have evidence of dual atrioventricular (AV) node pathways. BACKGROUND: Patients with a documented history of PSVT at times do not have inducible PSVT in the electrophysiology laboratory. Because dual AV node pathways serve as the substrate for AV node reentrant tachycardia (AVNRT), ablation of the slow pathway potentially may be useful in these patients. METHODS: The subjects in this prospective study were seven consecutive patients who underwent an electrophysiologic procedure because of documented PSVT and were found to have dual AV node physiology or inducible single AV node echo beats, but no inducible PSVT despite the administration of isoproterenol and atropine. Their mean (+/- SD) age was 33 +/- 13 years, and they had been symptomatic for 12 +/- 12 years. The frequency of the episodes of PSVT ranged from > or = 1/day to 1/month. The rate of the documented episodes ranged from 170 to 260 beats/min, and discrete P waves were not apparent. Slow pathway ablation was performed with 9 +/- 4 applications of radiofrequency energy using a combined anatomic and electrogram mapping approach. RESULTS: All evidence of dual AV node pathways was eliminated in six patients, and dual AV node physiology remained present in one patient. During a mean follow-up period of 15 +/- 10 months (range 8 to 27), no patient had a recurrence of symptomatic tachycardia (success rate 95% confidence interval 65% to 100%). CONCLUSIONS: Slow pathway ablation may be clinically useful in patients with documented but noinducible PSVT who have evidence of dual AV node pathways.

Adult↗
PubMed1996

2:1 atrioventricular block during atrioventricular node reentrant tachycardia.

OBJECTIVES: The purpose of this study was to determine the incidence and to clarify the mechanism of 2:1 atrioventricular (AV) block during AV node reentrant tachycardia induced in the electrophysiology laboratory. BACKGROUND: In patients with 2:1 AV block during AV node reentrant tachycardia, the absence of a His bundle potential in the blocked beats has been considered evidence of intranodal, lower common pathway block. METHODS: In consecutive patients with AV node reentrant tachycardia, the incidence of 2:1 AV block and the response to atropine and a single ventricular extrastimulus was observed. RESULTS: Persistent 2:1 AV block occurred in 13 of 139 patients with AV node reentrant tachycardia. A His bundle deflection was present in the blocked beats in eight patients and absent in five. Patients with 2:1 AV block had a shorter tachycardia cycle length than did patients without such block (mean +/- SD 312 +/- 32 vs. 353 +/- 55 ms, p < 0.01). Atropine did not alter the 2:1 block in any patient. In every patient, a single ventricular extrastimulus introduced during the tachycardia converted the 2:1 block to 1:1 conduction. CONCLUSIONS: The incidence of induced 2:1 AV block during AV node reentrant tachycardia is approximately 10%. The lack of a response to atropine and the consistent conversion of 2:1 block to 1:1 conduction by a ventricular extrastimulus indicate that, regardless of the presence or absence of a His bundle potential in blocked beats, 2:1 block during AV node reentrant tachycardia is due to functional infranodal block.

Adult↗
PubMed1996

Incidence of lead system malfunction detected during implantable defibrillator generator replacement.

Implantable cardioverter-defibrillator (ICD) generator replacement due to a depleted battery is a frequently performed procedure. The frequency with which sensing and defibrillation system failures are identified during device replacement procedures has not been previously described. Therefore, the purpose of this study was to prospectively determine the frequency of lead system malfunction detected at the time of device replacement in 55 consecutive patients undergoing ICD generator replacement. The mean age of the patients was 63 +/- 10 years and 40 of them were men. Forty-nine patients had an epicardial lead system, and six patients had a nonthoracotomy lead system. Four [7%] of these 55 patients were noted to have previously undetected lead system failure, either sensing (n = 3) or defibrillation (n = 1), necessitating system revision. The lead systems that failed were 40 +/- 6 months old (33-49 months). In summary, during ICD generator replacement, previously undetected problems with sensing or defibrillation may be identified in approximately 10% of patients. Therefore, a comprehensive evaluation of the sensing and the defibrillation functions should be an essential component of the ICD generator replacement procedure.

Defibrillators, Implantable↗
PubMed1996

Temperature and impedance monitoring during slow pathway ablation in patients with AV nodal reentrant tachycardia.

INTRODUCTION: Successful radiofrequency ablation of an accessory pathway has been demonstrated to be associated with an electrode-tissue interface temperature of approximately 60 degrees C or an impedance change of -5 to -10 omega. However, the temperature and impedance changes associated with ablation of AV nodal reentrant tachycardia (AVNRT) using the slow pathway approach have not been reported. Therefore, the purpose of this study was to define the temperature and impedance changes achieved during ablation of AVNRT: METHODS AND RESULTS: The study included 35 consecutive patients with AVNRT undergoing radiofrequency ablation of the slow pathway with a fixed power output of 32 W, and using a catheter with a thermistor bead embedded in the distal 4-mm electrode. The procedure was successful in each patient. The steady-state electrode-tissue interface temperature during successful applications of energy was 48.5 +/- 3.3 degrees C (range 42 degrees to 56 degrees C), and the steady-state temperature during ineffective applications was 46.8 degrees +/- 5.5 degrees C (P = 0.03). The mean impedance change during all applications of energy was -1.4 +/- 2.8 omega, and did not differ significantly during effective and ineffective applications. Coagulum formation resulted during five applications (2.7%) in two patients (5.7%). There were no recurrences during 114 +/- 21 days of follow-up. CONCLUSIONS: Successful ablation of AVNRT using fixed power output is achieved at an electrode-tissue interface temperature of approximately 48 degrees C and is associated with a drop in impedance of 1 to 2 omega. These findings suggest that slow pathway ablation requires less heating at the electrode-tissue interface than does accessory pathway or AV junction ablation.

Adult↗
PubMed1996

Randomized comparison of two techniques for titrating power during radiofrequency ablation of accessory pathways.

INTRODUCTION: The purpose of this study was to prospectively compare the value of impedance and temperature monitoring during accessory pathway ablation. Temperature and impedance monitoring can be used during radiofrequency ablation of accessory pathways to titrate power to achieve adequate but not excessive tissue heating. METHODS AND RESULTS: One hundred thirty-two patients with a single accessory pathway were randomly assigned to undergo ablation using either impedance monitoring or temperature monitoring. During impedance monitoring, the endpoint for titration of power was a 5- to 10-omega decrease in the measured impedance while for temperature monitoring the endpoint was to achieve a temperature of 58 degrees to 62 degrees C. Two protocols were used. In protocol 1 (90 patients), impedance monitoring was performed with a nonthermistor catheter and temperature monitoring was performed with a thermistor catheter. In protocol 2 (42 patients), a thermistor catheter was used in all patients. In protocol 1, the success rate (93% vs 93%; P = 1.0), ablation procedure duration (57 +/- 56 vs 41 +/- 41 min), fluoroscopy time (48 +/- 29 vs 41 +/- 23 min; P = 0.3), number of applications (6.2 +/- 4.7 vs 5.7 +/- 4.6; P = 0.8), and the number of applications associated with coagulum formation (0.1 +/- 0.3 vs 0.3 +/- 0.6; P = 0.1) were similar in the two groups. In protocol 2, as in protocol 1, there were no differences in the success rate (91% vs 95%; P = 1.0), ablation procedure duration (49 +/- 37 vs 62 +/- 55 min; P = 0.4), fluoroscopy time (46 +/- 24 vs 49 +/- 36 min; P = 0.8), number of applications (6.8 +/- 7.0 vs 7.8 +/- 12.1; P = 0.7), or number of applications associated with coagulum formation (0.3 +/- 0.6 vs 0.2 +/- 0.7; P = 0.6), between the impedance and temperature monitoring groups. CONCLUSION: Temperature and impedance monitoring are equally effective in optimizing the results of accessory pathway ablation.

Adult↗
PubMed1996

Inflammatory myopathy causing pharyngeal dysphagia: a new entity.

Seven patients presented to our swallowing center with solid food dysphagia. The age range at presentation was 69 to 90 years. All patients had normal findings on neurologic evaluation, and in those patients undergoing electromyography and nerve conduction studies, results of all such tests were also normal. Pooling of saliva in the pharyngeal recesses was noted on fiberoptic laryngoscopy in most cases. The swallowing videofluoroscopy findings were strikingly similar. All patients had a prominent cricopharyngeus muscle, and some had a prominence in a more proximal portion of the inferior constrictor muscle. All patients had decreased epiglottic tilt and moderate or severe residue in the pharyngeal recesses. Three patients underwent pharyngoesophageal sphincter myotomy. Biopsies of the omohyoid and cricopharyngeus muscles showed inflammatory myopathy with no evidence of inclusion bodies. This is a distinct clinical entity defined by isolated pharyngeal dysphagia in elderly patients with a unique videofluoroscopic appearance and pharyngeal myopathy.

Aged↗
PubMed1995

Hairy cell leukemia--an unusual presentation.

Hairy cell leukemia is a chronic lymphoproliferative disorder affecting middle-aged adults, with the median age of 50-55 years. The majority of the patients present with cytopenia. A high count is usually a feature of the hairy cell leukemia variant. We report a case of a 23-year-old male who presented with fever and cough of 15 days duration. His peripheral blood count was 63 x 10(9)/l. His peripheral blood and bone marrow smear showed hairy cells which were positive for tartarate-resistant acid phosphatase stain. Surface markers and electron microscopic study on peripheral blood ruled out hairy cell leukemia variant as a differential diagnosis.

Adult↗
PubMed1995

Assessment of pacing maneuvers used to validate anterograde accessory pathway potentials.

Four pacing maneuvers have been proposed to validate an anterograde accessory pathway potential (APP): (1) atrial pacing to induce complete block between the atrial electrogram and the APP; (2) ventricular pacing to advance the APP without altering the timing of the atrial electrogram; (3) atrial pacing to induce complete block between the APP and the ventricular electrogram; and (4) ventricular pacing to advance the ventricular electrogram without altering the timing of the APP. The purpose of this study was to assess these validation techniques by applying them to electrograms that simulated APPs but which were known to be atrial in origin. In 32 patients undergoing an electrophysiology procedure, a split atrial electrogram containing two components separated by at least 30 msec (mean 54 +/- 15 msec) was recorded. Using an atrial extrastimulus technique, complete block between the two components of the atrial electrogram (criterion 1) could never be induced, but complete block between the second component of the atrial electrogram and the ventricular electrogram (criterion 3) consistently was induced. Using a ventricular extrastimulus technique, the second component of the atrial electrogram consistently could be advanced by 10 to 40 msec without altering the timing of the first component (criterion 2). In addition, with ventricular pacing, the ventricular electrogram consistently was advanced without altering the timing of the two components of the atrial electrogram (criterion 4). In conclusion, among the four pacing maneuvers used to validate an anterograde APP, the only one that may be specific for an APP is the ability to induce complete block between the atrial electrogram and the APP.

Adult↗
PubMed1994

Evaluation of Geriforte, an herbal geriatric tonic, on antioxidant defense system in Wistar rats.

Geriforte, an herbomineral compound prepared from several herbs and minerals, is being used as a restorative tonic to solve the problems of old age in India. Since active oxygen species have been proposed to be involved in the aging process of the brain, alterations in the level of enzymes involved in the defense system against free radicals and other active oxygen species could substantially influence the aging process. Therefore, in the present study, this antistress adaptogenic Ayurvedic preparation has been evaluated for the activities of superoxide dismutase (SOD) and catalase (CAT), key enzymes of the cellular defense system, in the brain of aging Wistar male rats. The present study was carried out on 22-month-old rats. They were given Geriforte powder orally at a dosage of 900 mg/kg body weight once a day for two months. The Geriforte-treated rat brain had significantly high levels of SOD and CAT activities than those recorded in their respective controls. The contents of SOD and CAT in Geriforte-administered brain increased by 24% and 30%, respectively. In the present investigation, free radical damage was assessed by measuring thiobarbituric acid reactive substance (TBARS) in postmitochondrial fractions of brain homogenate. The magnitude of TBARS has been reported to be decreased by 26% in the Geriforte-treated rat brain. In conclusion, it seems logical to suppose that Geriforte, a combination of several plant ingredients and minerals, protects the body against the damaging effects of free radicals by producing large amounts of antioxidant enzymes.

Aging↗
PubMed1994

Preparation and fermentation of rice-defatted soy flour blends: effect on protein, fat and ash content.

Rice-defatted soy flour blends prepared in three proportions viz. 40:60, 50:50 and 60:40 were fermented with buttermilk at 25, 30 and 35 degrees C for 12, 18 and 24 h. Fermentation of these blends lowered the pH and raised the titratable acidity, maximum drop in pH and rise in titratable acidity being observed at 35 degrees C for 24 h. The fermentation either decreased or did not change the protein content of cereal-legume blends. Fat as well as ash content remained unaltered irrespective of temperature and time period of fermentation.

Fats↗