Biomedical subjects

H Bot

Publications and source records attributed to H Bot.

23 records · Page 2Linked to original sources

PubMedDate not supplied

Characterization of plaque components with intracoronary ultrasound imaging: an in vitro quantitative study with videodensitometry.

We investigated whether videodensitometry provides a possibility of objective plaque characterization by intracoronary ultrasound imaging. Histologically matched 30 MHz ultrasound images of characteristic atherosclerotic lesions in saline solution and blood-perfused human coronary arteries in vitro were digitized, and regions of interest were analyzed by calibrated videodensitometry. Pixel gray-level distributions were represented as frequency histograms, and mean pixel gray level, skewness, and kurtosis were calculated. Similarly, images of flowing blood in vitro (n = 9; hematocrit 40%) were analyzed. Mean pixel gray levels differed between the three lesion types (lipid rich [n = 6], 71 to 92 [mean 80]; fibromuscular plaque [n = 14], 94 to 162 [mean 124]; and calcified plaques [n = 8]; 161 to 196 [mean 178]) (all comparisons p < 0.001). Ranges of mean pixel gray levels for flowing blood in vitro were within the range of those for fibromuscular plaque (86 to 103; mean 98). During blood perfusion in nine specimens, pixel gray levels were 85% +/- 7% of those during saline perfusion but with similar differences between plaque types. We conclude that homogeneous plaque types can be distinguished in vitro by videodensitometry on intracoronary ultrasound images.

Aged↗

PubMedDate not supplied

Transesophageal echocardiographic assessment of systolic and diastolic dysfunction during percutaneous transluminal coronary angioplasty.

Left ventricular short-axis cross-sections at the level of the papillary muscles and transmitral flow were obtained with transesophageal echocardiography during percutaneous transluminal coronary angioplasty (PTCA) in 15 patients who had received anesthesia and who all demonstrated new areas of or more severe wall motion abnormality 10.2 +/- 4.3 seconds after initiation of balloon inflation. Both systolic (percentage area reduction and ejection fraction of the ischemic segment) and diastolic (early to atrial peak flow ratio and time velocity integral) function parameters and end-systolic wall stress changed significantly during PTCA. These changes were most profound during PTCA of the left anterior descending artery than they were during PTCA of the right coronary artery. Systolic and diastolic dysfunction are therefore invariably linked during transient ischemia, and PTCA of the left anterior descending artery consistently produced more profound dysfunction.

Angioplasty, Balloon, Coronary↗

PubMedDate not supplied

Free vortex ring formation in the left atrium originating in the left auricle.

An 80-year-old woman was evaluated by transesophageal echocardiography after coronary artery bypass surgery and subsequent cardioembolic stroke. In addition to spontaneous echo contrast demonstrating a counterclockwise rotating blood flow pattern, we observed free vortex ring formation in the left atrium, originating in the left auricle. To our knowledge, this is the first reported case of abnormal free vortex ring type flow pattern in the left atrium.

Aged↗

PubMedDate not supplied

Pulsed Doppler echocardiographic description of a circular flow pattern in spontaneous left ventricular contrast.

Pulsed Doppler echocardiography was performed in nine patients with spontaneous intracavitary dynamic echoes, revealing a circular flow pattern. All patients had a severely dilated left ventricle as a result of ischemic heart disease. The sample volume was placed in the apical four-chamber view near the lateral wall and near the interventricular septum, halfway between the mitral valve anulus and apex. A continuous (i.e., during both systole and diastole) positive signal was recorded near the lateral wall and a continuous negative signal at the interventricular septum. This indicates flow continuously toward the transducer along the lateral wall and away from the transducer along the interventricular septum. This is consistent with the circular flow pattern, as demonstrated by the spontaneous intracavitary dynamic echoes. In 22 normal volunteers a positive prominent shift was recorded during diastole near the lateral wall and either a negative (nine of 22) or no (13 of 22) shift at all during systole. Near the interventricular septum a negative systolic shift followed by a positive, early-diastolic shift was consistently recorded. In the large majority (18 of 22) negative waves were recorded during middle and late diastole. A continuous positive or negative Doppler signal was consistently absent in healthy subjects. The angle between the proximal part of the interventricular septum and the anterior mitral valve leaflet during maximal early diastolic opening in the patients was 74 +/- 4.8 degrees (mean +/- SD), which may give rise to a preferential eccentric inflow and the maintenance of the circular apical flow pattern.

Adult↗

PubMedDate not supplied

Predictive value of pulsed Doppler echocardiography in acute myocardial infarction.

In 60 consecutive patients with acute myocardial infarction early Doppler echocardiographic measurements of ventricular systolic and diastolic function were obtained and correlated with the degree of heart failure during the subsequent clinical course. Transmitral flow (early to atrial peak flow velocity ratio [E/A], systolic function measurements (maximal velocity at aortic anulus level [Vmax]), and time velocity integral (TVI) were obtained, as well as an "outflow tract ratio" (OTR), that is, measurement of the functional length of the left ventricular outflow tract. Spatial apical flow pattern was assessed with the sample volume positioned near the lateral wall and interventricular septum and by the simultaneous recording of apical and transmitral flow with a high pulse repetition frequency. Mean values of both E/A and systolic measurements of the entire group were used as cutoff values to identify patients with absent or mild heart failure defined as Killip I and II. E/A greater than 0.96 had a low specificity (45%) and positive predictive value (70%). Systolic function: Vmax greater than 0.66 m/sec, TVI greater than 12.6 cm, and OTR less than 0.48 had a specificity of 86%, 93%, and 93%, respectively, and a positive predictive value of 91%, 96%, and 96%. Normal spatial apical flow patterns demonstrated a specificity of 84% and positive predictive value of 91% to identify patients with infarctions who have a subsequent mild clinical course. Thus in contrast to E/A, both systolic function measurements and spatial apical flow patterns may identify on admission patients with a subsequent mild clinical course.

Adult↗