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Biomedical subjects

N C Nanda

Publications and source records attributed to N C Nanda.

228 records · Page 13Linked to original sources
PubMedDate not supplied

Computerized evaluation of blood flow measurement indices using Doppler ultrasound.

The study involved computer-assisted analysis of Doppler blood flow signals from an in vitro experimental system utilizing a calibrated occlusive pulsatile pump, vinyl tubings of various dimensions, and human blood. The power spectra of these signals were obtained using the Fast Fourier Transform, and the peak and mean frequencies along with the first moments of the Fourier spectra around the zero-frequency axis were computed. These indices were evaluated using different flow rates and tubal dimensions. It was experimentally verified that the first moment provided a more linear measure of volume flow rate than that estimated by peak and mean velocities. Although the first moment cannot measure the absolute flow rate, it may serve as a better indicator of relative flow changes than the other two indices.

Blood Flow Velocity↗
PubMedDate not supplied

Ultrasonic assessment of transposition of the great vessels.

Echocardiography can provide important diagnostic information that identifies the transposition complexes, evaluates relative pressure levels in the pulmonic and systemic circuits, describes subpulmonic obstruction, and identifies some associated congenital anomalies. Following the Mustard procedure, baffle dysfunction may be recognized, and the function of the procine heterograft used in the Rastelli procedure studied. Echocardiography can also demonstrate other congenital cardiac defects that may mimic transposition of the great vessels or reveal normal cardiac and great vessel anatomy and function that can reliably rule out the transposition complexes.

Echocardiography↗
PubMedDate not supplied

Influence of longer term left ventricular assist device support on valvular regurgitation.

The authors previously published data that describe acute alterations in ventricular dimensions and in the severity of mitral and tricuspid regurgitation (MR/TR) after initiation of left ventricular assist device (LVAD) pumping. In the current study, measurements of ventricular size and regurgitant jet area acquired after LVAD implantation are presented. Eight patients had LVAD implanted pending cardiac transplantation (duration of assist 70-279 days; mean, 162 +/- 29 days). Echocardiograms were obtained at the time of LVAD implant and later during LVAD support (mean time for late echo, 95 +/- 32 days post-implant). Comparisons of pre-implant with late post-implant data showed: increased TR jet area (4.8 +/- 1.0 cm2 vs. 8.0 +/- 1.7 cm2 P < 0.05); increased right ventricular (RV) end-systolic dimension (31 +/- 4 vs 40 +/- 5 mm, P < 0.05); and increased RV end-diastolic dimension (35 +/- 4 vs. 45 +/- 5 mm, P < 0.065). Decreased MR jet area and decreased LV dimensions (P < 0.05) also were noted on comparison of pre-implant and late post-implant data. There were no significant differences between any immediate post-implant and late post-implant echocardiographic measurements. No patient had clinical evidence of RV failure. LV mechanical assist causes an acute increase in TR, presumably by volume loading the RV. TR and RV enlargement persisted but did not discernibly worsen on subsequent post-implant echocardiograms. LV dimensions and MR remained less than the pre-implant values on later post-implant determinations.

Alkaline Phosphatase↗
PubMedDate not supplied

Transesophageal echocardiographic evaluation of coronary arteries for stenosis in the elderly patient.

This article documents the ability of transesophageal echocardiography to provide adequate images and clinically relevant information about the coronary anatomy of the elderly patient. Transesophageal echocardiography is commonly used to assess elderly patients who suffer cerebral vascular accidents. It is important to evaluate not only for the usually suspected causes of a cardiac source of emboli but also for direct and indirect evidence of coronary artery disease--the leading cause of death in the elderly stroke patient. Because atherosclerotic cardiovascular diseases identified in one vascular bed are prone to universally involve the other vascular territories to some degree, it is not surprising that the coronary arteries are often stenotic. As a sudden event with catastrophic symptoms, a stroke is commonly the first vascular event the elderly patient experiences. Depending on the degree of recovery, physical limitations may contribute to the lack of symptoms from coexistent peripheral or coronary artery disease. Transesophageal echocardiography may be the first, or only, coronary evaluation for high-risk elderly patients.

Aged↗