Search PubMed⌕ Search

Biomedical subjects

K K Talwar

Publications and source records attributed to K K Talwar.

At least 91 records · Page 5Linked to original sources
PubMed1989

Clinical significance of high frequency QRS potentials in myocardial infarction: analysis based on power spectrum of lead III.

Power spectrum analysis of ECG lead III QRS potentials using the Fast Fourier Transform technique was performed in 10 normal subjects and nine patients with inferior wall myocardial infarction (IWMI). A relative lowering in both low and high frequency QRS potentials was observed in the infarct group, in agreement with previous studies on power spectrum of lead II. However, contrary to earlier conclusions, the lowering was independent of a general attenuation in QRS voltages. Discriminant analysis of the frequency components showed that the high frequency components (190-310 Hz) were able to discriminate better between the two groups than the low frequency components (10-120 Hz).

Action Potentials↗
PubMed1989

Intravenous digital subtraction angiography in non-specific aorto-arteritis.

We have studied 40 patients with non-specific aorto-arteritis (Takayasu's disease) using intravenous digital subtraction angiography (DSA). The aorta, its major branches and (in 18 patients) pulmonary arteries were evaluated to determine the degree and extent of involvement. No complications related to the procedure were encountered. Good quality diagnostic images were obtained in 39 out of 43 instances. The unsuccessful examinations were in patients with congestive cardiac failure, and in one patient who would not co-operate. Aortic wall thickness and mild involvement of the descending aorta in the region of the diaphragm could not be assessed. Intravenous DSA is acceptable for the diagnosis and follow-up of aorto-arteritis in suitable patients.

Adolescent↗
PubMed1988

Myocardial involvement and its response to immunosuppressive therapy in nonspecific aortoarteritis (Takayasu's disease)--a study by endomyocardial biopsy.

Myocardial involvement in nonspecific aortoarteritis was evaluated in 16 patients (age 7-37 years, 2 males, 14 females) with the help of endomyocardial biopsy obtained from the right ventricle using the Cordis bioptome introduced from the right femoral vein. Morphological features of myocarditis were present in 8, endocardial thickening in 2, mild to moderate myofibre hypertrophy in 11, and a normal biopsy in 3 patients. Myocarditis was present in 8/11 cases with active disease and in none with inactive disease. Five of the 8 patients with myocarditis presented with congestive cardiac failure with 3 of them having no associated hypertension or valvar involvement to account for it. Immunosuppressive therapy was given to all patients with myocarditis. Serial studies (ongoing) showed clinical, haemodynamic and morphological improvement. Myocarditis appears to occur commonly in nonspecific aortoarteritis during the acute phase of the disease and may precipitate congestive cardiac failure in some patients. Immunosuppressive therapy shows promise and merits further evaluation.

Adolescent↗
PubMed1988

Spatial quantitative vectorcardiography in aortic stenosis: correlation with hemodynamic findings.

Thirty-four patients with hemodynamically documented valvar aortic stenosis without congestive heart failure were studied by the corrected Frank lead system vectorcardiography, with special emphasis on the angular characteristics of spatial R max to define the severity of the lesion. Spatial QRS-T angle demonstrated a highly significant correlation with the peak left ventricular systolic pressure (r = 0.72, P less than 0.001) and a significant correlation with peak transvalvar aortic gradient (r = 0.49, P less than 0.01). Furthermore, all patients with a QRS-T angle of more than 90 degrees had significant aortic stenosis (TVG greater than or equal to 50 mm Hg). The peak left ventricular systolic pressure and transvalvar aortic gradient also demonstrated a significant negative correlation with azimuth angle (r = -0.36 and -0.34, respectively; P less than 0.05) and a positive correlation with spatial R max magnitude (r = 0.38 and 0.41, respectively; P less than 0.05). There was no correlation between elevation angle of spatial R max and left ventricle systolic pressure or transvalvar aortic gradient. Our study indicates that spatial quantitative vectorcardiographic angular characteristics, particularly spatial QRS-T angle, may be a useful adjunct to other noninvasive techniques to assess the severity of valvar aortic stenosis.

Adolescent↗
PubMed1988

Myocarditis manifesting as persistent atrial standstill.

Persistent atrial standstill complicating inflammatory myocarditis in a young boy is presented. The disease was marked by a stuttering course characterized by intermittent return of atrial rhythm in the form of atrial flutter and fibrillation until persistent standstill lasting till the last follow-up occurred. The relevant literature is reviewed.

Adolescent↗
PubMed1988

Sudden bradyarrhythmic death in dilated cardiomyopathy: a case report.

An 18-year-old male presented with biventricular failure and atrial fibrillation. Detailed investigations revealed the diagnosis of dilated cardiomyopathy. He was put on medical treatment which resulted in symptomatic improvement. One year later he presented with 2 episodes of syncope, with no change in the routine electrocardiogram. A 24-hour ambulatory monitoring was done. The patient died suddenly while on the monitor. Analysis of the terminal event revealed a sudden complete heart block followed by asystole, an event described very rarely in the published literature.

Adolescent↗
PubMed1988

Evaluation of patients with bundle branch block and "unexplained" syncope: a study based on comprehensive electrophysiologic testing and ajmaline stress.

Thirty-five patients with bundle branch block (BBB) and unexplained syncope underwent electrophysiologic study (EPS) including programmed ventricular stimulation and ajmaline administration (1 mg/kg, IV) to induce infra-His block. A prolonged HV interval (greater than 55 ms) was present in 16 of the 35 patients. Ajmaline-induced HV block occurred in 12 patients (complete HV block in 10, and 2:1 HV block in two). Monomorphic ventricular tachycardia (VT) was inducible in nine (25.7%) and polymorphic VT in two patients (5.7%). Left ventricular ejection fraction (LVEF) was less than 40% in five patients (45.5%) with inducible VT. Two patients had an unexpected co-existence of inducible HV block and VT. The remaining 14 patients (40%) had no detectable abnormality. The incidence of inducible VT was higher (45% vs 13.3%), and the presence of negative studies was lower (30% vs 53.3%) in patients with structural heart disease (n = 20), when compared to those with no significant heart disease (n = 15) (differences not significant [NS]). During a mean follow-up period of 16.5 +/- 9.2 months, all the patients with inducible HV block have been asymptomatic after having received permanent pacemakers. Patients with inducible monomorphic VT (except one with poor left ventricular function who died suddenly) have also been asymptomatic on antiarrhythmic drugs. Of the remaining patients, seven with normal EPS, two with prolonged HV intervals but no inducible HV block (despite being given permanent pacemakers) and one patient with polymorphic VT on antiarrhythmic drugs continue to have recurrent syncope. Approximately 60% of patients with BBB and unexplained syncope have clinically significant electrophysiologic abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Electrophysiological studies in thyrotoxicosis with and without associated sick sinus syndrome.

Electrophysiological studies in 13 patients with thyrotoxicosis (5 men and 8 women, aged 17 to 76 years) are reported. Five patients presented with features of sick sinus syndrome (SSS) (Group A) while the remaining 8 patients (Group B) had no detectable cardiovascular abnormality. Sinus node function (corrected sinus node recovery and sinoatrial conduction time) was abnormal in all Group A but normal in Group B patients. Intra-atrial, artioventricular (AV) nodal, and infranodal conduction time and effective refractory period of atrium were normal in all patients in both groups. Effective refractory period of AV node was decreased in 6 patients (3 in each group). All Group A patients received radioiodine with complete clinical remission of sick sinus state in 4 subjects. Repeat electrophysiological studies in two of these patients, 6 and 12 months after treatment, showed complete normalization of sinus node function. This is the first reported electrophysiological study documenting the occurrence of SSS in thyrotoxicosis reversed by effective antithyroid treatment. We suggest that attempts should be made to identify underlying thyrotoxicosis in all patients with SSS, especially in the older age group. Appropriate medical treatment may prevent unnecessary implantation of permanent pacemakers in such patients.

Cardiac Pacing, Artificial↗
PubMed1987

Prognostic implications of complex ventricular ectopy in patients with and without structural heart disease. A study based on programmed electrical stimulation.

Fifty-six patients with complex ventricular premature beats (Lown grade IVa, IVb), but no evidence of ventricular tachycardia on 48 hours of continuous monitoring were evaluated by programmed electrical stimulation. Thirty patients had coronary atherosclerotic heart disease, 3 had valvular heart disease, 2 had cardiomyopathy and 21 had no structural heart disease. Programmed stimulation identified two groups of subjects: Group I comprised 11 patients in whom ventricular tachycardia was induced and Group II comprised 45 patients (which included 21 patients without heart disease) in whom no ventricular tachycardia was induced. The incidence of left ventricular dysfunction (ejection fraction less than 40%) was significantly higher in Group I as compared to Group II (P less than 0.001). There was, however, no difference between the grade of ventricular ectopy, HV interval or the incidence of bundle branch block between the 2 groups. Patients with inducible ventricular tachycardia (Group I) were put on laboratory directed anti-arrhythmic drug therapy. Patients without inducible tachycardia (Group II) were not given anti-arrhythmic therapy. The patients were followed up for 34 +/- 10 months. The incidence of sudden death (36.3% vs 6.6%, P less than 0.001) was significantly higher in Group I as compared to Group II. No patients without structural heart disease died during the follow-up. Programmed electrical stimulation fails to induce ventricular tachycardia in patients with complex ventricular ectopy but no structural heart disease. It is, however, possible to define a high risk subset in patients with structural heart disease and complex ectopy. The high risk patients with inducible ventricular tachycardia do not seem to benefit by anti-arrhythmic drugs, which may independently increase the risk of sudden death in treated patients. Patients in whom ventricular tachycardia is not inducible have better left ventricular function, a good long-term prognosis and do not require anti-arrhythmic agents.

Adult↗
PubMed1987

Ajmaline induced intra-Hisian block.

Ajmaline-induced block within the atrioventricular bundle (intra-Hisian) is rare. We report a 59-year-old male with a left bundle branch block in whom intravenous Ajmaline unmasked a latent conduction abnormality within the atrioventricular bundle. Relevant literature is reviewed.

Ajmaline↗
PubMed1986

The value of intracardiac electrophysiologic techniques in recurrent syncope of "unknown cause".

We prospectively evaluated and followed-up 45 patients with syncope in whom conventional cardiovascular and neurological investigations did not reveal the cause. All patients underwent electrophysiologic studies to assess the function of the sinus node and the integrity of atrioventricular conduction. These included the ajmaline test and the inducibility of supraventricular or ventricular tachycardia. Seven patients (15.5%) had evidence of sinus node dysfunction, 8 patients (17.7%) had evidence of infra-His atrioventricular block after ajmaline administration and 5 patients (11.1%) had inducible ventricular tachycardia. The remaining 25 patients (55.5%) had non-diagnostic studies. All patients with sinus node dysfunction and inducible infra-His atrioventricular block were asymptomatic during a mean follow-up period of 14.3 +/- 9.5 months after implantation of a permanent pacemaker. Patients with inducible ventricular tachycardia (except 1 with poor left ventricular function who died) were likewise asymptomatic while receiving laboratory guided anti-arrhythmic drug therapy. Twenty-five patients with non-diagnostic studies who were treated empirically are alive but the symptoms persist in 14 (56%). Provocative electrophysiological studies are of diagnostic and therapeutic utility in a significant number of patients with recurrent syncope of "unknown cause".

Adult↗
PubMed1986

Value of physical and pharmacological tests in predicting intrinsic and extrinsic sick sinus syndrome.

We studied 13 patients with sick sinus syndrome using various physical (postural reflex testing. Valsalva manoeuvre, carotid sinus massage), pharmacological (intravenous isoprenaline, atropine, neostigmine and total autonomic blockade) and electrophysiological tests in order to identify simple non-invasive markers of intrinsic sick sinus syndrome. Following autonomic blockade, 6 patients had normal and the remaining 7 had an abnormal intrinsic heart rate. Electrophysiological testing revealed abnormal sinus node parameters in 8 (62%) subjects in the basal state and 11 (85%) after autonomic blockade. Carotid sinus massage was abnormal in all patients (100%) with an abnormal intrinsic heart rate, and in only 2 of the 6 (33%) with normal intrinsic heart rate (P less than 0.05). The heart rate response to isoprenaline was abnormal in 5 of the 6 (83%) patients with normal as compared to only 1 of the 7 with abnormal intrinsic heart rate. With isoprenaline there was a significantly (P less than 0.05) higher increase in heart rate in patients with abnormal as compared to those with normal intrinsic heart rate. The other physical and drug tests were not helpful to differentiate between intrinsic and extrinsic mechanisms. Thus, carotid sinus massage and, to some extent, isoprenaline administration appear simple bedside tests which may be helpful in identifying the underlying mechanism of sick sinus syndrome.

Adult↗
PubMed1986

Noninvasive support for and characterization of multiple intranodal pathways in patients with mitral valve disease and atrial fibrillation.

Twenty-four-hour ambulatory ECG recordings were made in 22 patients with mitral valve disease and sustained atrial fibrillation. Computer analysis was used to stratify 64-beat periods according to the average ventricular rate levels. The distribution of pooled RR-intervals from heart-rate levels 50-60, 60-70 ... 160-170 were then presented as histograms, using a 20 ms width. This heart-rate stratified analysis revealed a bi- or trimodal RR-distribution in 16 of the 22 patients. This finding was interpreted as indicating the presence of two separate atrionodal pathways and in some cases nodal escape activity in addition. A limited heart-rate range may have obscured this phenomenon in 5 of the 6 cases without signs of bimodality. At high heart rates, AV-nodal conduction occurred via a 'fast pathway' whilst at successively lower heart rates, this conduction was blocked and a 'slower pathway' was used instead. In addition, at successively slower rates, the dominant cycle of conduction via either pathway tended to lengthen according to a linear relationship. The change of dominance from the fast to the slow pathway occurred between 90 and 120 beats per minute in almost all cases. The further electrophysiological characterization of patients with 2 pathways was done by calculation of differences and ratios between lengths of dominant cycles of different pathways at the rate of change of dominance. The findings may serve as reference data for further studies of AV-nodal conduction using the same method. Furthermore, the study strongly indicates that dual AV-nodal pathways are an ubiquitous phenomenon and supports the hypothesis that even in man, AV-nodal input follows two main routes: along the crista terminals between the coronary sinus and the tricuspid valve and from the interatrial septum.

Aged↗
PubMed1985

Paroxysmal vagally mediated AV block with recurrent syncope.

Paroxysmal complete atrioventricular (AV) block without associated electrocardiographic (ECG) abnormality is not a well recognized entity. A mother and her daughter had recurrent syncopal episodes, but a normal ECG. The episodes were preceded by nausea and vomiting. ECG during these episodes revealed complete heart block. In the mother, one episode was promptly reversed by atropine. Electrophysiological evaluation of the sinus and AV nodal function and atrial and ventricular effective refractory periods before and after autonomic blockade was normal. Provocative manoeuvres failed to induce AV block. Paroxysmal AV block was vagally mediated in one of the patients, as indicated by prompt response to atropine. In the second case, the vagal dependence could not be proved but appears to be the most likely explanation. It thus appears that paroxysmal, vagally mediated complete AV block should be seriously considered in patients with unexplained syncope.

Adult↗