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Biomedical subjects

S Radhakrishnan

Publications and source records attributed to S Radhakrishnan.

At least 55 records · Page 3Linked to original sources
PubMed1990

Doppler assessment of interventricular pressure gradient across isolated ventricular septal defect.

Continuous wave Doppler ultrasound was used to estimate the pressure gradient between the right and left ventricle for assessment of pulmonary arterial systolic pressure in 30 patients with isolated ventricular septal defect and for subsequent comparison with similar data obtained on cardiac catheterization. The age of the patients ranged from 8 months to 45 years (6.8 +/- 8.6 years). No patient had right or left ventricular outflow tract obstruction. Doppler measurements were done within 24 h of cardiac catheterization. Pressure gradient across ventricular septal defect on cardiac catheterization ranged from 7 to 95 mmHg (48 +/- 24 mmHg) and that on Doppler assessment ranged from 8 to 78 mmHg (42 +/- 20 mmHg). Doppler measurements of interventricular pressure gradient correlated well with those obtained on cardiac catheterization (r = 0.90, p less than 0.001). Correlation was better in patients with pressure gradient across ventricular septal defect less than 75 mmHg (r = 0.96). Correlation was poor in three of five patients with very small ventricular septal defects (interventricular pressure gradient greater than 75 mmHg) because the jet used was not ideal. Thus continuous wave Doppler ultrasound is an accurate noninvasive means of measuring pressure gradient across ventricular septal defect, which is a useful parameter for assessment of pulmonary artery systolic pressure in patients with isolated ventricular septal defect without right and left ventricular outflow tract obstruction.

Adolescent↗
PubMed1990

Echocardiographic demonstration of resolving intrapericardial mass in tuberculous pericardial effusion.

A patient with tuberculous pericardial effusion is described who presented with cardiac tamponade. Subsequent to pericardiocentesis, a large echodense intrapericardial mass was observed which disappeared completely with antituberculous chemotherapy. The resolution of the mass suggests that it was a conglomeration of fibrinous exudates deposited in the pericardial cavity. Presence of such exudates should not be considered an indication for surgical intervention.

Echocardiography↗
PubMed1990

Epidemiological study of coronary heart disease in urban population of Delhi.

A community based survey of coronary heart disease (CHD) was carried out on a random urban sample of 13,723 adults in the age group 25-64 yr in Delhi, India. CHD was diagnosed either on the basis of clinical history supported by documentary evidence of treatment in a hospital or at home; or on ECG evidence in accordance with the Minnesota Code. The overall prevalence of CHD based on clinical history, was 31.9 (39.5 in males and 25.3 in females) per 1000 adults in this age group. The number of patients with CHD increased with advancing age in both sexes. The total prevalence rate based on both clinical history and ECG criteria (asymptomatic patients with ECG changes of definite myocardial infarction and ST-T changes suggestive of CHD) was estimated as 96.7/1000 adults in this age group. Analysis of information on socio-economic status, family history of CHD, obesity, hypertension and smoking obtained from this sample of 13,723 adults suggested that hypertension had the strongest association with CHD. Obesity, diabetes and family history were also found to be associated with CHD. It should, however, be noted that risk factor assessments in CHD can be done satisfactorily only through incidence studies.

Adult↗
PubMed1990

Prevalence, awareness & treatment status of hypertension in urban population of Delhi.

A community based survey for the prevalence of hypertension was carried out on a random urban sample of 13,723 adults in the age group 25-64 yr from the Union Territory of Delhi (India). Hypertension was defined as systolic pressure greater than 160 mm Hg and/or a diastolic pressure greater than 90 mm Hg or a history of current antihypertensive medication. The overall prevalence rate/1000 adults was 127.5 (116.6 in males and 136.8 in females). Mild hypertension (diastolic pressure between 91-104 mm Hg) predominated in the whole group, the proportion decreasing with increasing age in both sexes. Fifty per cent of the hypertensives were aware of their problem, the awareness being slightly higher in females (51.8% versus 46.5%). Approximately 30 per cent of the hypertensives were on medication for high blood pressure. The status control of blood pressure was low in the population, being only 9 per cent, with little difference between the two sexes. The study emphasises the enormity of the problem of hypertension in an urban population in India and poor control of blood pressure achieved in the community.

Adult↗
PubMed1989

Doppler echocardiographic assessment of transmitral gradients and mitral valve area before and after mitral valve balloon dilatation.

This is a comparative study of 60 sets of observations of mitral valve end-diastolic gradient, mean diastolic gradient, and mitral valve area obtained by Doppler echocardiography and cardiac catheterization. The studies were performed in 28 patients, 16 of whom underwent mitral valve balloon valvuloplasty. These 16 patients had studies performed before, immediately after valvuloplasty, and one week later. Thus 28 studies were performed before or without valvuloplasty (Group I) and 32 after valvuloplasty (Group II). The time interval between Doppler echocardiography and cardiac catheterization was less than 24 hours in 44 studies and 24 to 72 hours in 16 studies. In Doppler echocardiography the gradients were obtained by simplified Bernoulli's equation and the mitral valve area by pressure half-time method. There was excellent correlation between end-diastolic gradients (r = 0.96, p less than 0.001) and mean diastolic gradients (r = 0.92, p less than 0.001) measured by the two techniques. A statistically significant correlation also existed in the mitral valve area values (r = 0.53, p less than 0.005). On separate analysis Group I showed excellent correlation for all three variables (r values of 0.90, 0.87, and 0.82 for end-diastolic gradients, mean-diastolic gradients, and mitral valve area, respectively). Group II also showed excellent correlation of end-diastolic gradients (r = 0.80) and mean diastolic gradients (r = 0.87), but poor correlation of the mitral valve areas (r = 0.17; p = NS) by the two techniques. Doppler echocardiography can accurately measure transmitral gradients both before and after valvuloplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

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

Comparative Doppler evaluation of the monostrut and older convexo-concave Björk-Shiley mitral prosthetic valve.

Doppler echocardiography was performed in 104 patients with a Björk-Shiley prosthetic valve in the mitral position. Valves of size 25 mm and 27 mm were inserted in 39 and 65 patients, respectively. Each valve had two models; the older convexo-concave model (22 and 40, of 25 and 27 mm size, respectively). Inflow velocities were recorded using Doppler techniques and the gradients calculated using the Bernoulli principle. The area of the mitral valve was determined by the T1/2 method. Comparison of the two models for both sizes did not reveal any significant differences in either the gradients across the valves or the area of the valve. Trivial mitral regurgitation was detected in a higher percentage of monostrut valves (18% and 20% for the 25 and 27 mm older convexo-concave models and 59.9% and 52% for the 25 and 27 mm monostrut valve). We conclude that the newer monostrut model of the Björk-Shiley valve in the mitral position does not offer any additional haemodynamic benefit.

Adolescent↗
PubMed1989

Infective endocarditis following patch closure of ventricular septal defect: a cross-sectional Doppler echocardiographic study.

Cross-sectional and Doppler echocardiographic characteristics of infective endocarditis are described in six cases following patch closure of a ventricular septal defect. The patients presented to us with fever one to five months after surgery. Five of them also had congestive cardiac failure. Cross-sectional echocardiography showed large masses over the patch in all cases. Dehiscence of the lower end of the patch was identified in three of them, and, in two cases, the right sinus of Valsalva had ruptured into the right ventricle. Doppler detected turbulent flow in the right ventricle in five cases, and a continuous signal indicating an aorto-right ventricular communication in two cases. A signal indicative of aortic regurgitation was also found in the latter two cases. Staphylococcus aureus was cultured from the blood in three cases and Aspergillus was identified at autopsy in one. The echocardiographic findings were confirmed in three cases (one during surgery and two at autopsy). Dehiscence of the patch and large masses were associated with a poor prognosis.

Adolescent↗
PubMed1989

Echocardiographic diagnosis of a left atrial thrombus in a patient with normal prosthetic mitral valve.

A 20-year-old male with a Björk-Shiley mitral valve prosthesis on optimal anticoagulation and antiplatelet drug therapy presented with systemic embolization 11 months after mitral valve replacement. Cross-sectional and Doppler echocardiography revealed a left atrial thrombus attached to the posterior wall of the left atrium and normal function of the prosthetic valve. The findings were confirmed at surgery.

Adult↗
PubMed1989

Fixed subaortic stenosis with congenital aneurysm of sinus of Valsalva--cross-sectional and Doppler echocardiographic diagnosis of a rare association.

A 13-year-old girl was diagnosed by cross-sectional and Doppler echocardiography to have the rare combination of congenital aneurysm of the right sinus of Valsalva rupturing into the right ventricular outflow tract and a discrete subaortic fibrous shelf with severe subvalvar stenosis, moderate aortic regurgitation and left ventricular dysfunction. The findings were confirmed at cardiac catheterisation and surgery.

Adolescent↗
PubMed1989

Maternal determinants of intra-uterine growth retardation.

Forty mothers with full term low birth weight babies and 30 age-matched mothers with full term normal birth weight babies were studied to find out the relative incidence of common maternal aetiological factors in the causation of intra-uterine growth retardation (IUGR). Attention was focussed to find out the relevance of the following factors: Age of the mother, weight of the mother, incidence of toxaemias of pregnancy, haemoglobin and serum protein values. It was observed that there was a statistically significant correlation between the incidence of IUGR and maternal weight of less than 45 kg and of toxaemia of pregnancy. Also, there was an increased association of IUGR with decreased value of haemoglobin and serum protein in mothers.

Adult↗
PubMed1988

Doppler echocardiography in the diagnosis of divided left atrium (cor triatriatum sinister).

A case of congenitally divided left atrium detected on cross-sectional echocardiography is described. Simultaneous Doppler examination helped to diagnose the obstructive nature of the partition within the left atrium by locating a turbulent high velocity (2.2 meters/second) diastolic signal. The diagnosis was confirmed on cardiac catheterization and surgery.

Blood Flow Velocity↗
PubMed1988

Non-invasive diagnosis of ruptured sinus of Valsalva aneurysm by pulsed Doppler echocardiography.

Six cases of ruptured aneurysm of the sinus of Valsalva into the right ventricle, including two post-operative patients with residual murmurs have been reported. Complete diagnosis, including that of residual and associated defects, was made non-invasively using cross-sectional and pulsed Doppler echocardiographic studies. The exact site of rupture was localized by a continuous flow signal in the right ventricle. The diagnosis was subsequently confirmed by cardiac catheterization and angiocardiography in each case.

Aortic Aneurysm↗
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↗