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Biomedical subjects

M L Bhatia

Publications and source records attributed to M L Bhatia.

At least 55 records · Page 3Linked to original sources

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↗

Coronary arteritis in nonspecific aortoarteritis.

Nonostial distal coronary artery involvement in nonspecific aortoarteritis is rare. We report a 35-year-old patient with features of nonspecific aortoarteritis who had an inferolateral myocardial infarction and on coronary angiography was shown to have severe disease of the left circumflex artery in its middle third.

Adult↗

Quantitative assessment of pulmonary hypertension in patients with rheumatic heart disease using continuous wave Doppler ultrasound.

The accuracy of Doppler ultrasound in estimating pulmonary arterial systolic pressure non-invasively was evaluated in 50 patients with rheumatic heart disease. In all cases, the maximal velocity of the tricuspid regurgitation jet was measured by continuous wave Doppler ultrasound and the systolic pressure gradient between right ventricle and the right atrium was calculated by the modified Bernoulli equation. There was a close correlation between Doppler estimated and hemodynamically measured transtricuspid systolic gradient (r = 0.86, P less than 0.001). Right ventricular systolic pressure, which equals pulmonary arterial systolic pressure in the absence of right ventricular outflow obstruction, was calculated by adding a constant of 10 to the Doppler gradient and also by using a regression equation. Right ventricular systolic pressure obtained by both of these Doppler methods correlated closely with values at cardiac catheterization (r = 0.82 and 0.83, respectively). Our study suggests that pulmonary arterial systolic pressure can be determined non-invasively with accuracy, by Doppler ultrasound, in patients with rheumatic heart disease.

Adolescent↗

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↗

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↗

Myocardial infarction in young Indian patients: risk factors and coronary arteriographic profile.

One hundred four patients (101 men, three women), under 40 years of age, with myocardial infarction (MI), underwent coronary arteriography. Eighty patients had significant obstructive coronary artery disease (CAD) (group 1), 23 had normal coronary arteries (group 2), and one patient had coronary ostial stenosis as a result of nonspecific aortoarteritis (group 3). Coronary risk factors in group 1 included smoking (76.2%), hypercholesterolemia (36.3%), hypertension (32.5%), positive family history (28.7%), and diabetes mellitus (5%). Multiple risk factors were frequent (56.2%). Smoking was common (p less than 0.01) and diabetes mellitus less frequent (p less than 0.05) as compared to older (greater than 40 years) patients with MI and arteriographically proved CAD. The frequency of one-, two-, and three-vessel disease was 33.7%, 26.2%, and 40%, respectively, in group 1. Group 2 patients were almost devoid of coronary risk factors. The only group 3 patient had left coronary ostial stenosis with no risk factors. Similar to their counterparts in developed countries, young Indian patients with MI and obstructive CAD have a high frequency of coronary risk factors, especially smoking and severe multiple-vessel disease. Since normal coronary arteriograms are also frequent in this setting, a detailed evaluation is recommended for purposes of prognosis and management.

Adolescent↗

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↗

Significance of advanced atrioventricular block in acute inferior myocardial infarction--a study based on ventricular function and Holter monitoring.

Eighty-two consecutive patients with a first inferior wall acute myocardial infarction were evaluated by radionuclide angiography and 24-hour Holter monitoring during their hospital stay. The patients were divided into two groups. The first group (n = 28) had advanced atrioventricular block, while the second group (n = 54) were without atrioventricular block. The patients with advanced block had lower left ventricular (49 +/- 12% vs. 55 +/- 14%, P less than 0.05) and right ventricular ejection fraction (26 +/- 10% vs. 43 +/- 11%, P less than 0.001) than those with normal atrioventricular conduction. The atrioventricular block disappeared spontaneously in all of them. The hospital mortality of the patients with advanced block and those without advanced block was 10.7 and 5.5%, respectively (P = NS). Pre-discharge 24-hour Holter monitoring done in all survivors revealed isolated ventricular ectopics (Lown grade I, II, III) in 44% of patients who had had advanced block and 43.1% of patients without advanced block (P = NS). Complex ventricular ectopics (Lown grade IVa, IVb), however, were recorded in significantly more patients with advanced block as compared to patients without advanced block (36 vs. 7.8%, P less than 0.01). Most patients with complex ventricular ectopics in both groups had impaired left or right ventricular function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

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↗

HLA, blood groups and secretor status in patients with established rheumatic fever and rheumatic heart disease.

The distribution of HLA-A, -B and -DR antigens as well as blood groups and secretor status was studied in sporadic, North Indian patients of rheumatic fever and rheumatic heart disease. While HLA-Aw33 occurred with an increased frequency in the patient group (X2 = 4.01), no statistically significant differences were observed in the frequency of B-locus antigens. In the DR locus, HLA-DR3 was found to be significantly increased (50% vs 26.1%, X2 = 13.8) and DR2 significantly reduced (21.8% vs 47.0%, X2 = 15.6). Also, there was a preponderance of non-'O' blood group individuals in the patient group as compared to controls. The DR3 association was significant only in those patients of RHD who did not have any previous history of rheumatic fever. These results indicate that susceptibility to rheumatic heart disease is HLA-class II mediated, with HLA-DR3 influencing susceptibility and DR2 conferring protection.

ABO Blood-Group System↗