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Biomedical subjects

K K Talwar

Publications and source records attributed to K K Talwar.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Late rhythm abnormalities after surgical repair of tetralogy of Fallot: noninvasive and invasive evaluation.

Twenty five patients aged 6 to 35 years (mean +/- SD: 14.2 +/- 7.1 years), surgically corrected for tetralogy of Fallot (TOF) more than one year ago, were assessed for rhythm abnormalities by resting electrocardiogram (ECG), twenty-four hours ambulatory ECG monitoring, signal averaged ECG and electrophysiological studies. An X-ray chest for assessing heart size, two dimensional and Doppler echocardiography for residual defects and radionuclide angiography for resting left ventricular ejection fraction were also done. Eight out of 25 (32%) patients were found to have significant rhythm abnormalities. Ventricular arrhythmias were detected in four patients. In two, ventricular tachycardia was induced during electrophysiologic studies, being sustained in one. Multiform ventricular ectopics were observed in two other patients. All these patients were operated, after the age of 10 years, and three of them are presently more than 20 years old. Cardiomegaly was present in the chest X-ray in three patients, and significant residual pulmonary stenosis was seen in one patient. Left ventricular ejection fraction was reduced in two, while signal averaged ECG was positive in one of the three cases subjected to this investigation. Supraventricular tachycardia (SVT) was observed in three patients. This was diagnosed by ambulatory ECG monitoring in all but in addition, was also inducible in one patient on electrophysiologic testing. There was no correlation of the occurrence of SVT with age or age at correction for TOF. None of these patients had any residual defect, cardiomegaly or subnormal left ventricular ejection fraction. Transient complete heart block requiring temporary pacing was documented in one patient with a large residual ventricular septal defect.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Ultrastructural and histological study of endomyocardial biopsies from patients of dilated cardiomyopathy--a comparative evaluation and their clinical correlation.

Morphological studies of dilated cardiomyopathy reveal nonspecific light and electron microscopic features. This study was designed to perform a comprehensive qualitative and semi-quantitative evaluation of histological and ultrastructural parameters in endomyocardial biopsies in 20 cases of DCM. Semi-quantitation of parameters increases the accuracy and precision of evaluation by reducing interobserver variation in assessment. The semi-quantitative score ratios in our study were further correlated with the clinical and hemodynamic data to identify parameter(s) of prognostic significance. In the histological evaluation, myofibre hypertrophy appeared to be the most frequent (95%) and severely affected parameter followed by myocardial degeneration (70%). The ultrastructural features were more diffuse, impressive and severely altered. The most prominent features were mitochondrial degeneration and myofibrillar lysis seen in 100% of our cases. Severe mitochondrial degeneration appeared to be an indicator of poor prognosis in DCM as it was seen in patients with the lowest left ventricular ejection fraction obtained angiographically. Moreover, unlike the light microscopic evaluation, ultrastructural score ratios correlated significantly with the ejection fraction.

Adult↗
PubMedDate not supplied

Immunohistochemical characterisation and quantitative evaluation of lymphomononuclear cells in dilated cardiomyopathy-an endomyocardial biopsy study.

Endomyocardial biopsies (EMB) from patients of dilated cardiomyopathy (DCM) and normal hearts were evaluated for infiltration by lymphomononuclear cells. Cryostat sections from cases of DCM were stained with antisera against leucocyte common antigen (LCA), Pan T lymphocytes and macrophages. Paraffin sections from patients of DCM and normal hearts were also stained with a panel of antisera against LCA, and macrophage markers namely, lysozyme, alpha-1-antitrypsin (AAT) and alpha-1-antichymotrypsin (ACT). The stained cells were quantitated and expressed as number of cells/mm2. Comparisons were made between the number of lymphomononuclear cells in hematoxylin and eosin stained sections and those stained by various markers. Light microscopic evaluation of paraffin sections of EMB in all cases of DCM showed mild to moderate hypertrophy of the myocardium in 20 and 10 patients respectively. Only mild focal myonecrosis was observed in 14 patients. These foci showed minimal infiltration by lymphomononuclear cells. In normal hearts, occasional small foci of lymphomononuclear cells were seen within the interstitium. The number of LCA positive cells in the frozen section from cases of DCM were more (7.03 +/- 3.15/mm2) than the number of cells in the corresponding paraffin sections (5.26 +/- 1.14/mm2), thus indicating that antigens are possibly better preserved in frozen sections. In normal hearts, the number of cells staining positively with LCA were almost identical (4.81 +/- 1.14/mm2) to those seen in paraffin sections of cases of DCM (5.26 +/- 1.61/mm2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Radiofrequency ablation of idiopathic ventricular tachycardia.

Eleven patients (9 male, 2 female) with ventricular tachycardia (VT) and structurally normal heart underwent radiofrequency (RF) ablation of VT focus. The detailed electrophysiological mapping localized the VT focus in the left ventricular (LV) apicoseptal region in 5, LV posteroseptal region in 2, right ventricular (RV) outflow tract in 2 and RV midseptal and inflow regions in one patient each. The technique of endocardial activation mapping during VT, pacemapping and the presence of His-Purkinje potential (for LV focus) were used to identify the precise site of delivery of RF energy. The procedure was successful in 9 patients. There was no complication. The mean fluoroscopic time was 45 +/- 21 (range 20-120) minutes. RF ablation is effective and may be considered as therapy of choice for patients with ventricular tachycardia and normal heart.

Adolescent↗
PubMedDate not supplied

In-hospital results of radiofrequency ablation of supraventricular tachycardia.

Two hundred and one consecutive patients with symptomatic paroxysmal supraventricular tachycardia (PSVT) underwent a diagnostic electrophysiological test and catheter ablation with radiofrequency (RF) current. In 102 (51%) patients, the mechanism of PSVT was found to be atrioventricular nodal reentry (AVNRT, typical in 101, atypical in 1). Atrioventricular reentrant tachycardia (AVRT) involving accessory pathway was present in 94 (47%) and ectopic atrial tachycardia in 5 patients. A successful outcome was achieved in 100 of 102 patients (98%) with AVNRT and in 85 of 94 patients (90%) with AVRT. The anatomical approach was used for ablation in patients with AVNRT. The focus was ablated in 4 patients with ectopic atrial tachycardia whereas it was modified in the remaining one patient. Procedure-related complications occurred in 4 patients (2 AVNRT, 2 AVRT). One patient each developed haemothorax, pericardial effusion, mitral valve endocarditis and high-grade AV block requiring permanent pacemaker implantation. The electrode and ablation catheters were repeatedly used after ethylene oxide sterilisation to reduce the cost of the procedure. RF ablation is an effective, safe and curative modality of treatment for patients with symptomatic PSVT due to AVNRT and AVRT. The experience with this modality in patients with ectopic atrial tachycardia is limited.

Adolescent↗
PubMedDate not supplied

Morphological evaluation of endomyocardial biopsy.

Endomyocardial biopsy (EMB) has evolved as a simple and safe procedure with minimal morbidity and mortality. It is performed via the transvascular approach and can be done either as an individual procedure or, more commonly, at the time of routine cardiac catheterization. Sequential biopsies can be performed without ill-effects. Conventionally, the right ventricle is biopsied through the transvenous approach. It has been shown that biopsies from the right side are adequately representative if the disease is biventricular. The left ventricle can be biopsied in disease states affecting that chamber, viz. left ventricular tumour or predominant involvement of the left ventricle in endomyocardial fibrosis. For proper evaluation, biopsy pieces need to be handled and processed carefully. A large amount of valuable information can be retrieved from routinely processed tissue-a process which can be done in all laboratories. Important indications for EMB include diagnosis and monitoring of cardiac allograft rejection, adriamycin toxicity and diagnosis and follow up of myocarditis. Pathologists need to be aware of inherent artefacts of the biopsy procedure and should interpret these with caution. Thus, EMB provides useful information for diagnosis, follow up, monitoring of therapy and studying the evolution of several cardiac disorders.

Biopsy↗
PubMedDate not supplied

Serial echocardiography in transplanted heart: an initial report of five cases.

Role of echocardiography including Doppler is established in selection of donor and in the care of patients after cardiac transplantation. Its value for recognition of transplant rejection is however still evolving. We present here, serial echocardiographic findings in five male patients, aged 22 to 46 years who underwent cardiac transplantation at our institution. There was no appreciable change on follow-up in the left ventricular dimensions, thickness of left ventricular posterior wall and interventricular septum and left ventricular systolic function. Transient pericardial effusion was noted in two patients. Trivial to mild mitral and tricuspid regurgitation was observed. The diastolic function of the left ventricle, as assessed by mitral valve inflow wave pattern, was normal in four patients. However in the fifth patient, there was evidence of diastolic dysfunction of the left ventricle and this change was accompanied by rejection episode (IIIB changes) in the endomyocardial biopsy. With resolution of rejection in biopsy, the diastolic function by Doppler also returned to normal. We conclude that echocardiography has a definite role in the general care of patients after cardiac transplantation. Transient small pericardial effusion and mild atrioventricular valve regurgitation are common after the operation. Echocardiography may also be of use in recognition of rejection episode by demonstrating evidence of diastolic dysfunction of the left ventricle. Currently, endomyocardial biopsy remains the gold standard for diagnosis of rejection.

Adult↗
PubMedDate not supplied

Aortoaortic bypass: indications, techniques and results.

The standard surgical treatment of complex cases of aortic obstructions is difficult and sometimes even hazardous, thus necessitating the use of alternative surgical methods to manage these cases. Between 1986 and 1995, nine such patients underwent ascending aorta to descending/abdominal aorta bypass graft as an alternative procedure at a premier medical institution. There was no hospital death nor any significant morbidity. Preoperative systolic blood pressure in right upper limb ranged from 150 mm Hg to 230 mm Hg (mean 180.5 mm Hg) while postoperative systolic blood pressure in right upper limb ranged from 126 mm Hg to 150 mm Hg (mean 134 mm Hg), thereby showing marked improvement. Preoperative pressure gradient across the aortic obstruction ranged from 50 mm Hg to 120 mm Hg (mean 87.2 mm Hg). It was relieved in all except two patients who had resting gradients of 10 mm Hg and 12 mm Hg respectively. All the patients were relieved of their symptoms. After a mean follow-up of 33.3 months (range 6 to 108 months), all the patients are in New York Heart Association (NYHA) class I with evidence of good distal perfusion. This technique of bypassing the aortic obstruction has the added advantage of avoiding the complications associated with standard technique.

Adult↗
PubMedDate not supplied

Analysis of local electrograms at successful and unsuccessful sites for slow pathway ablation of atrioventricular nodal reentrant tachycardia.

Anatomic and electrogram approaches have been described for ablation of slow pathway in patients with atrioventricular nodal tachycardia. The purpose of this study was to identify parameters to predict successful slow pathway ablation using the anatomic approach. Local electrograms at successful and unsuccessful sites were compared in 36 patients undergoing slow pathway ablation using anatomic approach. A total of 208 local electrograms were studied. Fragmented atrial electrogram was seen in 24/36 (67%) of successful and in 46/172 (26%) of unsuccessful sites (p < 0.001). The sensitivity, specificity and positive and negative predictive values of fragmented atrial electrogram were 67, 73, 34 and 91 percent respectively. A slow pathway potential was noted in three of successful sites. There was no difference in the atrial to ventricular amplitude ratio in these sites. In conclusion, fragmentation of atrial electrogram and presence of possible slow pathway potential are seen more often at successful than at unsuccessful sites. In our opinion, while using an anatomic approach for slow pathway ablation, an analysis of local electrogram may help in identifying the proper site and avoiding unnecessary radiofrequency energy delivery.

Adult↗