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Biomedical subjects

K K Talwar

Publications and source records attributed to K K Talwar.

At least 73 records · Page 4Linked to original sources
PubMed1991

Lone atrial fibrillation with complete heart block in a child.

An asymptomatic 9-year-old boy presented with a slow heart rate and a structurally normal heart. He was detected to have complete atrioventricular block and fine atrial fibrillation that was not evident on the surface electrocardiogram. This case appears to be an unusual example of a disease of the cardiac conduction system presenting in childhood.

Atrial Fibrillation↗
PubMed1991

Value of exercise vectorcardiography and exercise radionuclide ventriculography in identification of coronary arterial disease in patients with left bundle branch block.

Twelve patients (8 male and 4 female, age ranged 39-60 years) with suspected coronary arterial disease with left bundle branch block were evaluated for ischemia by simultaneous exercise vectorcardiography and radionuclide-ventriculography. Selective coronary angiography revealed normal coronary arteries in 5 and significant coronary arterial disease in 7 patients. Radionuclide ventriculography revealed no significant difference in resting left ventricular ejection fraction in patients with normal coronary arteries (44.0 +/- 13.9%) and coronary arterial disease (45.7 +/- 11.9%). Exercise radionuclide ventriculography showed positive response suggestive of ischemia in 11 patients (11/12), including all 5 with normal coronary arteries and 6/7 with coronary arterial disease. The magnitude of spatial 'R' maximum cardiac vector in both groups at rest (normal coronary arteries: 1.61 +/- 0.22 mV, coronary arterial disease: 1.63 +/- 0.35 mV) did not show any significant difference. On exercise, the magnitude of spatial 'R' maximum cardiac vector uniformly increased in patients with normal coronary arteries (1.61 +/- 0.22 to 1.75 +/- 0.25 mV, P less than 0.01) and decreased in 6 and remained unchanged in 1 patient with coronary arterial disease (1.63 +/- 0.35 to 1.34 +/- 0.46 mV, P less than 0.01). There was no change in rotational characteristics of QRS and T loops at end exercise in either group. Our preliminary observations indicate that exercise induced alteration of the magnitude of the maximal spatial 'R' cardiac vector appears to be an useful parameter to diagnose underlying coronary arterial disease in patients with left bundle branch block. Having a high false positive response, exercise radionuclide ventriculography appears to be of limited value in these patients.

Adult↗
PubMed1991

Persistent atrial standstill--clinical, electrophysiological, and morphological study.

Persistent atrial standstill (PAS) is a rare disorder characterized by absence of atrial activity on the surface and intracavity electrograms, absence of atrial mechanical activity, and inability to electrically stimulate the atria. Four patients (ages 18-60 years) with PAS were evaluated. One of these (no. 3) only had right atrial (RA) standstill, whereas left atrium (LA) showed spontaneous activity and could be stimulated electrically. As RA biopsy is not possible, right ventricular (RV) endomyocardial biopsy (EMB) was obtained to identify possible atrial pathology that revealed inflammatory myocarditis, 2; amyloidosis, 1; and myocardial hypertrophy with fibrosis, 1. Three patients were given permanent pacemakers. One of these with amyloidosis died suddenly. One is lost to follow-up. The others cases are persisting with PAS.

Adolescent↗
PubMed1991

Non-specific aorto-arteritis (Takayasu's disease) in children.

Digital subtraction panaorto-arteriography was performed in 32 consecutive children (21 females, mean age 10.8 years) with non-specific aorto-arteritis to assess digital subtraction angiography (DSA) in imaging these children and to study the patterns of involvement in the Indian sub-continent. Diagnostic quality DSA images were obtained in 21 out of 27 intravenous and nine out of 11 intra-arterial studies. Obstructive lesions were present in all the patients and commonly involved the abdominal aorta (24 patients) and renal arteries (20 patients). Aneurysms were seen in five patients and predominantly involved the descending thoracic aorta. Pulmonary artery involvement was uncommon (five out of 20 patients) and clinically silent. Based on clinical and angiographic features, percutaneous transluminal angioplasty was performed for the management of uncontrolled hypertension in eight patients (10 lesions). Initial success was obtained in eight procedures (80%). Re-stenosis occurred after 5.5 months in one patient, but was successfully re-dilated. The follow-up period ranged between 5 and 16 months (mean 9 months). Long-term efficacy of transluminal angioplasty in the management of these children is awaited.

Adolescent↗
PubMed1991

Clinical and angiographic features of nonspecific aorto-arteritis in children and adults.

We compared clinical and angiographic features of nonspecific aorto-arteritis in children with those of adult patients. Digital subtraction angiography by i.v. and/or i.a. injection was carried out in 104 patients. In group 1, consisting of 32 patients aged 16 years and younger, hypertension (75%) was the most common clinical feature, followed by diminished pulse, bruit (72% each), congestive cardiac failure (38%), and limb claudication (13%). Obstructing arterial lesions were always present and commonly involved the abdominal aorta (75%), descending thoracic aorta (41%), renal (63%) and subclavian (41%) arteries. In Group 2, consisting of 72 patients more than 16 years of age, arterial bruit (91%), and diminished pulse (82%) were the most common symptoms. Hypertension occurred in 61%, congestive failure in 14%, and limb claudication in 30%. Obstructing lesions were always seen and commonly involved the abdominal aorta (77%) and renal arteries (64%). Involvement of the descending thoracic aorta (26%) was less common but subclavian (57%) and carotid (24%) arteries were more commonly involved than in group 1. Arterial aneurysms and pulmonary involvement were uncommon in both groups. There were some clinical and angiographic differences in nonspecific aorto-arteritis between children and adults but these were statistically insignificant (chi-square test).

Adolescent↗
PubMed1990

Myocarditis and myocardial interstitial fibrosis in constrictive pericarditis--an extended pathological spectrum?

We performed endomyocardial biopsy in six patients with constrictive pericarditis, revealing the presence of myocarditis and myocardial interstitial fibrosis in all regardless of the endocardial thickening. These findings suggest that the presence of endomyocardial involvement in the setting of restrictive heart disease should not be deemed specific for endomyocardial fibrosis when the clinical evaluation suggests constrictive pericarditis.

Endomyocardial Fibrosis↗
PubMed1990

The incidence and patterns of pulmonary artery involvement in Takayasu's arteritis.

The pulmonary arterial anatomy in 44 patients with Takayasu's arteritis was examined by intravenous digital subtraction angiography (IV-DSA) on an outpatient basis using centrally delivered, small-volume, bolus injections of an ionic, water soluble contrast medium. Diagnostic pulmonary angiograms were obtained in 42 patients (95.4%) without complication. Angiographically evident pulmonary arterial involvement was seen in six patients (14.3%). The pulmonary involvement was not suspected clinically in any patient and the chest radiographs were abnormal in only two patients (33%). The angiographic spectrum of systemic arterial involvement was the same irrespective of the presence or absence of pulmonary arterial involvement. The pulmonary arterial pressures were measured in two patients with abnormal pulmonary angiograms and were found normal. Follow up IV-DSA in one of these patients 16 months after immuno-suppressive therapy showed no change in the pulmonary angiographic picture.

Adult↗
PubMed1990

The association between aneurysm formation and systemic hypertension in Takayasu's arteritis.

We have studied the incidence and patterns of aneurysm formation in 88 consecutive patients with Takayasu's arteritis by utilizing digital subtraction pan-aortoarteriography by the intravenous and/or intra-arterial route. Seventy-two patients underwent initial intravenous angiography of which 64 (89%) were diagnostic. All the intra-arterial studies (n = 24) were diagnostically adequate. Arterial aneurysms were seen in eight patients (9.1%) and the saccular variety (75%) was the most common. Clinical and angiographic features of these eight patients were compared with those of the remaining patients. No major differences were observed except that longstanding uncontrolled hypertension was present in all patients with aneurysm formation. In comparison, hypertension was observed in 30 (49.2%) of the remaining 61 patients in whom clinical details were available. Angiographic localization of the aneurysm is important since there are no clinical features that distinguish these patients and rupture of a strategically located aneurysm can prove fatal. The association between hypertension and aneurysm formation suggests that hypertension in these patients should be aggressively managed at the onset of disease. In this regard percutaneous transluminal renal angioplasty may prove a possible management adjunct.

Adolescent↗
PubMed1990

Histomorphologic characteristics of endomyocardial fibrosis: an endomyocardial biopsy study.

Endomyocardial biopsies from right, left, or both ventricles were performed in 13 angiographically documented cases of endomyocardial fibrosis. The endocardium was appreciably thickened due to acellular hyalinized collagen tissue in all cases. Variable amounts of elastic tissue intimately admixed with fibrous tissue were recognized. A "zonal layering" pattern of the endocardium was absent. Thrombus, inflammatory cells, and granulation tissue at the endomyocardial interphase, and eosinophils within the biopsy were not seen. In addition, lymphomononuclear interstitial inflammatory infiltrates were seen in five cases.

Adolescent↗
PubMed1990

Initial experience with percutaneous transluminal angioplasty in the management of Takayasu's arteritis.

We have performed percutaneous transluminal angioplasty (PTA) for 15 arterial stenoses in 11 patients with Takayasu's arteritis. The lesions included tight, proximally located renal artery stenosis (12 stenoses; nine patients), localized abdominal aortic stenosis (two patients) and occluded left common iliac artery (one patient). Clinically successful dilatation was achieved in seven patients (10 stenoses) with renal artery stenosis, in both the patients with abdominal aortic stenosis and in the only patient with an occluded left common iliac artery. No complications related to the procedure were encountered. The follow-up period (n = 7) ranged between 1 and 16 months, mean follow-up period after renal angioplasty was 5 months and after abdominal aortic angioplasty was 12.5 months. Initial success has been maintained in both the patients with abdominal aortic stenoses and in four out of five patients with renal artery stenosis. Percutaneous transluminal angioplasty offers an attractive alternative for the management of stenosing lesions in Takayasu's arteritis with good short term results.

Adolescent↗
PubMed1989

Spatial vectorcardiogram in acute inferior wall myocardial infarction: its utility in identification of patients prone to complete heart block.

Spatial vectorcardiography was performed in 28 (22 males, 6 females; age 36-78 years) consecutive cases of acute inferior wall myocardial infarction during sinus rhythm within 24 hours of admission. Orthogonal leads using the corrected Frank lead system were recorded at a paper speed of 100 mm/sec. Qualitative analysis consisted of study of QRS loop inscription in all 3 orthogonal planes. Additional quantitative analysis using the spherical coordinate system was undertaken to measure the magnitude and angular direction (azimuth and elevation angle) of spatial R maximum cardiac vector. During the hospital course, 15 patients developed transient complete heart block and 13 patients did not. The direction of the QRS loop inscription in the 3 planes did not differ between the two groups. The spatial R maximum magnitude and azimuth angle did not differ between the patients who developed complete heart block and those who did not. Values for elevation angle were markedly different between the two groups. The spatial R maximum elevation angle ranged from 0 to -35 degrees and was negative (superiorly directed) in 14 of the 15 patients with complete heart block, whereas it ranged from -10 degrees to +/- 75 degrees and was negative (superiorly directed) in only 2 of the 13 patients without this complication. Thus it appears that negative elevation angle of spatial R maximum cardiac vector in patients with inferior wall myocardial infarction may indicate proneness to complete heart block.

Adult↗
PubMed1989

Evaluation of spatial R maximum cardiac vector changes in exercise testing: pre-exercise versus post-exercise measurements.

R wave amplitude changes during exercise have been a controversial issue as both increase and decrease in amplitude have been reported in patients with coronary arterial disease. This variability in response is attributed to change in position and heart axis on exercise. In view of this limitation, this study evaluated the change in spatial R maximum amplitude on exercise, which should not be affected by the above factors. Twenty patients with ischaemic heart disease (male 20, age 38-61 years) and 9 control subjects (male 9, age 32-65 years) were studied. Orthogonal leads, X, Y, Z were recorded using corrected Frank lead system on a stereokinematic vectorcardiograph (Tonnies). The magnitude of spatial R maximum cardiac vector increased from 0.1 to 0.6 mV in 8/9 control subjects and decreased or showed no change in 18 of the 20 patients with coronary arterial disease. In the control group, the mean value at the end of exercise (0.98 +/- 0.34 mV) was significantly less (P less than 0.01) as compared to pre-exercise value (1.09 +/- 0.2 mV). Our preliminary observations thus indicate that, with exercise, the magnitude of spatial R maximum cardiac vector decreases or shows no alteration in height in patients with coronary arterial disease whereas it increases in normal subjects.

Adult↗
PubMed1989

Prediction of terminal atrial myocardial repolarisation from incomplete phase 3 data.

The duration of the monophasic action potential (MAP) carries prognostic antiarrhythmic information when the recording is done during sinus rhythm (SR) after DC conversion of atrial fibrillation (AF). This study analyses whether it is possible to predict MAP duration during sinus rhythm by analysing the atrial MAP during AF, even though complete myocardial repolarisation is never reached during this arrhythmia. We have therefore evaluated the estimated duration of the action potential (AP) and MAP by exponential extrapolation of phase 3 data. (1) AP studies were done on 11 human atrial myocardial specimens. Resting membrane potential (RMP) and AP duration were better identified when more data obtained during repolarisation were used for prediction. Thus the predicted RMP deviated on average by -0.4% of AF amplitude from the real RMP level when data to 90% repolarisation were used for extrapolation. AP duration at 90% repolarisation correlated well with the real AP duration (r = 0.88) at this level of data aquisition. (2) Continuous recording of atrial MAPs was done in 15 patients during AF and in 12 of these during SR after DC conversion. Resting myocardial repolarisation level during AF, RP(EST), and estimated MAP duration, MAPD(EST), could be calculated by exponential extrapolation in 12 patients. The actual repolarisation during fibrillation reached below 90% of the RP(EST) level in eight patients and below 70% in all 12. The MAP duration during SR could be predicted with increasing precision when data closer to the RP(EST) were used for calculation of MAPD(EST). Thus MAPD(EST) correlated well with SR MAP duration when data reaching at least 90% of RP were used (r = 0.85).(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗