Automated on-line quantification of left ventricular ejection fraction by echo.

An automated border detection system based on the acoustic back scatter property of ultrasound has been recently developed. This provides beat-to-beat values for the left ventricular ejection fraction (EF). This study assesses the reliability of this method when compared with the angiocardiographic EF, and manual 2D-echo-derived EF based on the modified Simpson method. Angiocardiographically-derived EF was used as the gold standard. In a total of 49 patients the angiocardiographic EF was found to be 64.49 +/- 15%. It showed excellent correlation with the automated border detection-derived EF (r = 0.91). The automated border detection-derived EF also showed excellent correlation with the manual 2D-echo method (r = 0.9). In addition, automated border detection requires less time than the manually drawn method (40.9 +/- 7.7 sec versus 58.6 +/- 7.5 sec; p < 0.001). We conclude that the acoustic quantification of the EF correlates well with the angiocardiographically-derived EF and is less time-consuming.

Serum troponin-T in acute myocardial infarction.

This study was carried out to assess the utility of serum troponin-T estimation in the diagnosis of acute myocardial infarction (AMI). One hundred and twenty two consecutive patients presenting with Q wave myocardial infarction were included in the study. In patients with AMI, serum troponin-T level was significantly elevated (4.21 +/- 3.49 ng/ml) on the first day of AMI (normal = 0.1 ng/ml). The elevated serum levels were detected even on the second (4.82 +/- 3.01 ng/ml) and the 3rd day (5.83 +/- 3.83 ng/ml) of AMI. Our results thus indicate that serum troponin-T is elevated twenty eight folds on the first day of AMI and the levels remain elevated as long as the third day. Hence, troponin-T can be used as sensitive biochemical marker of AMI, both in the immediate as well as in the early phase of myocardial infarction.

Proximal flow convergence method in the assessment of mitral stenosis.

Mitral valve area (MVA) was calculated using the proximal flow convergence method in 60 patients with severe mitral stenosis. Using the apical 4 chamber view, colour Doppler was used to measure the peak forward flow rate. From this, the mitral valve area was calculated according to the formula: mitral valve area = peak forward flow rate/peak mitral velocity. This method compared well with the established 2D planimetry derived valve area (r = 0.89) and Doppler pressure half time method (r = 0.88). Hence, this can be used as an alternative method to estimate the valve area in patients with mitral stenosis.

M-mode echocardiographic diagnosis of left ventricular hypertrophy.

To assess the utility of various primary and derived M-Mode Echocardiographic parameters for the purpose of defining left ventricular hypertrophy (LVH), 74 subjects with LVH were subjected to M-mode echocardiographic examination. It was concluded that except for cross sectional area, the other echocardiographic parameters performed too poorly to be of any clinical utility for defining LVH by echocardiography.

Evaluation of clinical variables as predicators of left ventricular function in acute myocardial infarction.

In 43 rural patients, all survivors of acute Myocardial infarction, left ventricular function was studied by 2-D echocardiography and evaluated in relation to 18 clinical predictors of left ventricular function. The mean left ventricular ejection fraction (LVEF) was 41.53 +/- 12.92% as compared to 70.02 +/- 7.02% in 506 healthy controls. LVEF was dichotomised at < 40% (n = 24) and > 40% (n = 19). Out of various clinical variables analysed following were found to be strong predictors of low LVEF. S3 gallop (p < 0.001) pulmonary rates (p < 0.001); Creatine phosphokinase > 200 I.U. (p < 0.001); Cardiomegaly on X-ray (p < 0.001); pulmonary congestion on chest X-ray (p < 0.001); and proportional pulse pressure (p < 0.001). There was a stepwise decline in the LVEF for each additional clinical variable. The over all predictive accuracy was 90%. It is concluded that readily obtainable clinical variables provide a useful bedside method of estimating LVEF after acute myocardial infarction.

Left ventricular M-mode echocardiographic measurements of Indian population.

The left ventricular dimensions of 506 normal healthy subjects (men = 317, women = 189) in the age group of 17 to 80 years were measured echocardiographically. The measurements were found to differ significantly from the western data. A separate limit for left ventricular echocardiographic parameter for the normal Indian population was established.

Left ventricular mass by M-mode echocardiography.

A comparison of various M-mode echocardiographic methods for assessment of left ventricular mass (LVM) was done in 21 subjects. The anatomical LVM was taken as Standard; it varied from 64.55 to 341.82 g. Of the six different M-mode echo methods compared, the method of Devereux and Reichek (1977) was found to correlate best with anatomical LVM (r = 0.99; SD = 49.54). By this method LVM = 1.4 [(LVIDd + LVPWTd + IVSTd)3 - (LVIDd)3] - 14 g.

Left ventricular muscle mass by echocardiography: methodology.

The limitations of electrocardiography for diagnosing left ventricular hypertrophy (LVH), due to unacceptable accuracy and lack of serial quantifications, are well known. The use of angiocardiography for LVH assessment is invasive, hazardous and costly. Echocardiography provides an excellent method of estimation of left ventricular muscle mass, which is simple, non-hazardous, accurate and reproducible.

Left ventricular mass in normal Indian population.

A prospective study was conducted to ascertain the distribution of the left ventricular mass in normal adult Indian population and to establish the upper limit of the same. Four hundred and eighty normal subjects (men = 310; women = 170), in the age group of 18 to 60 years were screened echocardiographically, to estimate the left ventricular mass. The left ventricular mass in men was found to be 124 +/- 32 gm whereas in women it was 93 +/- 37 gm. The upper limit of the left ventricular mass (mean +/- 2 SD) was found to be 189 gm and 167 gm, for men and women respectively. The left ventricular mass in both men and women correlated with the body weight (r = 0.51, p less than 0.001; r = 0.22, p less than 0.001), height (r = 0.27, p less than 0.001; r = 0.22, p less than 0.01), and the body surface area (r = 0.49, p less than 0.001; r = 0.27, p less than 0.001), whereas it was found to be independent of age (r = 0.01, p = NS; r = 0.10, p = NS). In men alone the diastolic blood pressure influenced the left ventricular mass (r = 0.27, p less than 0.001), otherwise the left ventricular mass was independent of systemic blood pressure variations within the normal range. The left ventricular mass in the present study differs significantly from the Western population.