R Ajay Kumar

Bio: R Ajay Kumar is an academic researcher. The author has contributed to research in topics: Ventricle & Systole. The author has an hindex of 2, co-authored 3 publications receiving 12 citations.

Quantitative evaluation of left ventricle performance from two dimensional echo images.

Abstract: Objectives We sought to quantify the left ventricle systolic dysfunction by a geometric index from two-dimensional (2D) echocardiography by implementing an automated fuzzy logic edge detection algorithm for the segmentation. Background The coronary injuries have repercussions on the left ventricle producing changes on wall contractility, the shape of the cavity, and as a whole changes on the ventricular function. Methods 2D echocardiogram and M-mode recordings were performed over the control group and those with the dysfunctions. From 2D recordings, individual frames were extracted for at least five cardiac cycles and then segmentation of left ventricle was done by automated fuzzy systems. In each frame, the volumes are measured and a geometric index, eccentricity ratio (ER), was derived. The endocardial fractional shortening (FS), midwall fractional shortening (mFS), and the relative wall thickness (RWT) were also measured in each case. Results Depressed value of endocardial FS (20.39 +/- 5.43 vs 34.28 +/- 9.36, P = 0.0046), mFS (33 +/- 8.3 vs 52.5 +/- 11.7, P = 0.0047), and the RWT (0.337 +/- 0.096 vs 0.525 +/- 0.119, P = 0.0002) was observed with dysfunction. ER measured at end-diastole (2.86 +/- 0.703 vs 4.14 +/- 0.38) and end-systole (3.14 +/- 0.79 vs 5.48 +/- 0.74) was found to be decreased in the dysfunction group and more significant at the end-systole (P = 0.00017 vs 6.6E-06). Conclusion This work concludes that the regional and global left ventricle systolic dysfunction can be assessed by the ER measured at end-diastole and end-systole from 2D echocardiogram and may contribute to the high rate of cardiovascular disorders.

Detection of left ventricle systolic dysfunction from shape deformity.

Abstract: Coronary artery disease producing ischemic cardiomyopathy is the most frequent cause of left ventricular systolic dysfunction. Non-ischemic cardiomyopathies can also produce systolic dysfunction; they may be inherited as genetic disorders or occur sporadically. These coronary injuries have repercussions on the left ventricle producing changes on wall contractility, the shape of the cavity and also changes on ventricular function. This study is focused on the 2D echocardiograms of the left ventricle. Apical two chamber and four chamber view recordings were performed on normal and systolic dysfunction subjects. Individual frames were extracted for at least five cardiac cycles. After preprocessing these images, segmentation of the left ventricle was performed by Fuzzy systems. Then the volumes were measured by single and biplane methods along with the perimeter, short axis length and long axis length in each frame, from which the two indices Sphericity Index (SI) and Normalized Eccentricity Index (NEI) was determined. It was found that the diastolic phase is short in the case of systolic dysfunction, and its volume variation is not uniform as in the normal case. Also, in the case of systolic dysfunction, the span of either the long or short axis length variation is less than 0.5 cm. This depicts that akinesis is in the corresponding direction; the value of SI is less than 2 for systolic dysfunction. A sharp peak is seen at each systole point in the NEI plot and also its variation is smooth in subjects having LVEF > 45%, which is not the case for dysfunction.

Left Ventricular Systolic Dysfunction Identification by Motion Analysis

Abstract: This paper presents a new technique for identification of regional dysfunctions in the left ventricle from 2-D echocardiography. It uses a novel left ventricular border tracking algorithm based on fuzzy inference system. In this paper we show how the regional dysfunction present in the left ventricle can be identified by tracking the movement of centre of mass of left ventricle in a 2D space. The path pattern of that point traced over the cardiac cycles shows variation between the two groups. The main advantage of this proposed approach is the smaller date handling in regional dysfunction identifications unlike other existing methods. The method is illustrated on the real 2D echocardiograph dataset that includes patients having dysfunctions in the left ventricular wall. The diagnostic potential of this method is explained in detail

Accuracy of cardiac function and volume status estimates using the bedside echocardiographic assessment in trauma/critical care.

Abstract: Background: Critically ill patients often require invasive monitoring to evaluate and optimize cardiac function and preload. With questionable outcomes associated with pulmonary artery catheters (PACs), some have evaluated the role of less invasive monitors. We hypothesized that the Bedside Echocardiographic Assessment in Trauma (BEAT) examination would generate cardiac index (CI) and central venous pressure (CVP) estimates that correlate with that of a PAC. Methods: BEAT was performed on all SICU patients with a PAC in place. Prospective data included stroke volume and the inferior vena cava (IVC) diameter. The CI was calculated and correlated with that from the PAC. Each CI was then categorized as low, normal, or high. The IVC diameter was used to estimate the CVP. The association between the BEAT and PAC estimates of CI and CVP was evaluated using x 2 . Results: Eighty-five BEAT examinations were performed, 57% on trauma and 37% on general surgery patients. Fifty-nine percent of the CI examinations and 97% of the IVC examinations contained quality images. Of these, the overall correlation coefficient was 0.70 (p < 0.0001). When CI was categorized, there was a significant association between the BEAT and PAC (p = 0.021). There was a significant association between the CVP estimate from the BEAT examination and the PAC (p = 0.031). Conclusion: Our data show a significant correlation between the CI and CVP estimates obtained from the BEAT examination and that from a PAC. BEAT provides a noninvasive method of evaluating cardiac function and volume status. Bedside echocardiography is teachable and should become a part of future critical care curricula.

Is echo-determined left ventricular geometry associated with ventricular filling and midwall shortening in hypertensive ventricular hypertrophy?

Abstract: Background: The correlation between left ventricular (LV) geometry, mass, diastolic function, and midwall fractional shortening (MFS) in hypertensive patients with left ventricular hypertrophy (LVH) is not well established owing to limited diffusion of MFS evaluation. The aim of the study was to evaluate this correlation in 1887 consecutive hypertensive patients, all affected by LVH (mean age 66 years, 924 males), with LV ejection fraction (LVEF) >45% for early detection of ventricular dysfunction rather than LVEF and diastolic function impairment. Methods and Results: All patients underwent M-B mode echocardiography and PW-Doppler evaluation. LV geometry and mass were compared with Doppler-determined mitral flow and tissue velocities. LV geometry was eccentric (E) for 1018 subjects (53.9%) and concentric (C) for 869 (46.1%). There was no difference concerning LV diastolic dysfunction (P: n.s.) between 576 (30.6%) of the ELVH and 368 (19.4%) of the CLVH patients. The following parameters showed significant statistical differences: LV MFS impairment (P < 0.01) between 86 (4.6%) of the ELVH and 177 (9.4%) of the CLVH patients. LV MFS impairment rate was higher in 171 patients without LV diastolic dysfunction (9.1%), than in 92 patients affected (4.9%, P < 0.02). In CLVH patients, a higher prevalence of LV MFS impairment was observed in 143 without LV diastolic dysfunction (7.6%), than in 34 patients affected (1.8%, P < 0.01). In ELVH patients, a lower prevalence of LV MFS impairment was observed in 28 without diastolic dysfunction (1.5%), than in 58 patients affected (3.1%, P < 0,03). Conclusion: Midwall LV impairment, an independent predictor of cardiac death and morbidity in hypertensive patients, can allow early identification of patients with LV dysfunction even when LVEF or assessment of diastolic function are normal. LV MFS impairment rate is higher in CLVH patients, and even higher when considering only those CLVH patients with no diastolic dysfunction. These results suggest that the ventricular dysfunction with normal LVEF is not always due to diastolic dysfunction, but often to systolic dysfunction as assessed by MFS impairment, an important early sign of ventricular dysfunction in hypertensive patients, even when diastolic function is normal.

Echocardiographic parameters that predict outcome in aortic atresia patients undergoing comprehensive stage II procedure.

Abstract: Background. The hybrid procedure is one option for palliating patients with hypoplastic left heart syndrome. As experience increases with this palliation, the physiology and its influence on outcome can be better assessed. The goal of this study was to determine if echocardiographic parameters correlate with post-operative variables in patients with aortic atresia undergoing the comprehensive Stage II procedure. Methods. Retrospective chart review on all patients with aortic atresia, who underwent the comprehensive Stage II procedure from January 2002 to December 2008, was performed. Echocardiographic indices were evaluated and correlations were made with peri-operative and hospital variables. Pair-wise Pearson's correlation tests were used to analyze the associations between continuous measures. Results. Thirty-four patients met inclusion criteria. Age at comprehensive Stage II procedure was 0.45 ± 0.13 years and body surface area was 0.31 ± 0.04 m2. Right ventricle (RV) percentage change was 45 ± 10%, eccentricity index was 1.96 ± 0.45, estimated systemic cardiac output was 7.68 ± 2.56 L/min/m2 and estimated effective systemic cardiac output was 5.15 ± 2.24 L/min/m2. Retrograde patent ductus arteriosu (PDA) velocity time integral (VTI) correlated with log pre-bypass lactate and maximum lactate (r = 0.53, 0.44). PDA regurgitant fraction correlated with log post-bypass lactate, length of intubation, and urine output on day four (r = 0.39, 0.46, −0.37). RV percentage change correlated with log pre-bypass lactate, and urine output on days four and five (r =−0.38, 0.43, 0.54). No echocardiographic parameter predicted renal or liver insufficiency, dialysis, extracorporeal membrane oxygenation use, or hospital death. Conclusion. Retrograde PDA VTI and RV percent change correlated with some peri-operative variables though no echocardiographic parameter was associated with any major morbidities or mortality. Newer echocardiographic techniques may better predict comprehensive stage II outcomes.

Sequential functional analysis of left ventricle from 2D-echocardiography images.

Abstract: The sequential changes in shape of left ventricle (LV), which are the result of cellular interactions and their levels of organizational complexity, in its long axis view during one cardiac cycle are obtained. The changes are presented in terms of shape descriptors by processing of images obtained from a normal subject and two patients with dilated left ventricular cardio-myopathy. These images are processed, frame by frame, by a semi-automatic algorithm developed by MATLAB. This is consisting of gray scale conversion, the LV contour extraction by application of median and SRAD filters, and morphological operations. By filling the identified region with pixels and number of pixels along its contour the area and perimeter are calculated, respectively. From these the changes in LV volume and shape index are calculated. Based on these the stroke volume (SV) and ejection fraction (EF) are calculated. The changes in LV area, perimeter, volume and shape index in cardiac patients are less than that of normal subject. The calculated SV and EF of normal subject are within the range as obtained by various imaging procedures.