PubMed Health⌕ Search

Biomedical subjects

A F Parisi

Publications and source records attributed to A F Parisi.

153 records · Page 9Linked to original sources
PubMedDate not supplied

Cardiovascular changes in pregnancy evaluated by two-dimensional and Doppler echocardiography.

During pregnancy significant cardiovascular changes occur. To study these anatomic and physiologic changes we performed two-dimensional and Doppler echocardiography in 28 women during the third trimester (34.4 +/- 1.9 weeks) of pregnancy and then again after delivery (7.8 +/- 2.2 weeks). Fourteen nonpregnant age- and sex-matched subjects served as controls. Left ventricular diastolic and systolic dimensions were similar among pregnant, postpartum, and control subjects. Left atrial area as determined by two-dimensional echocardiography was significantly larger during pregnancy (16.7 +/- 4.0 cm2) compared with measurements postpartum (13.8 +/- 3.1 cm2) and with controls (15.5 +/- 3.5 cm2) (p less than 0.01). Doppler study showed that the ratio of early diastolic flow velocity to late diastolic flow velocity (E/A max) and E/A integral were lower among pregnant subjects (1.3 +/- 0.3, 2.0 +/- 0.5) compared with postpartum subjects (1.6 +/- 0.4, 2.5 +/- 1.5) and controls (1.9 +/- 0.5, 3.0 +/- 0.8) (p less than 0.05). Heart rate was higher among pregnant subjects (84 +/- 10 beats/min) compared with postpartum subjects (70 +/- 16) and controls (69 +/- 13) (p less than 0.05). In summary, in pregnant subjects during late third trimester left ventricular chamber dimensions were similar to these postpartum measurements in control subjects; however, the left atrium is dilated during pregnancy. Although there are significant alterations in Doppler-derived left ventricular diastolic parameters during the third trimester, increased heart rate and a dilated left atrium may explain these findings.

Adult↗
PubMedDate not supplied

Clinical validation of an edge detection algorithm for two-dimensional echocardiographic short-axis images.

The purpose of this study was to validate an edge detection algorithm for short-axis two-dimensional echocardiographic studies in a protocol that stimulated its implementation at multiple clinical laboratories. Six short-axis two-dimensional echocardiographic studies were solicited from each of five clinical laboratories. A single cardiac cycle from each of the resulting 30 studies was entered into the computer system. Five expert observers came to the laboratory on separate occasions and traced endocardial borders from the short-axis studies on 2 separate days. The computer algorithm generated borders on each frame of the cardiac cycles on the basis of regions of search defined by the observers. Of the 30 original studies, five were considered excellent, seven were good, nine were poor, and nine were technically inadequate by consensus of the five observers. The correlation coefficient for computer-defined borders with manually defined borders in the excellent quality studies was 0.985. Interobserver variability was expressed as the mean percent area difference for all possible pairings of observers. The mean percent area differences were decreased from +/- 9.8% to +/- 5.3%, +/- 12.5% to +/- 8.4%, and +/- 17.4% to +/- 15.6% when comparing observer with computer-generated borders in the excellent, good, and poor quality studies, respectively. Intraobserver variability was expressed as decrease in mean percent area difference on corresponding frames between days 1 and 2. Intraobserver variability was decreased from +/- 6.5% to +/- 4.5%, +/- 10.8% to +/- 7.0%, and +/- 14.0% to +/- 11.9%, respectively. All reductions in variability were statistically significant at p less than 0.01. Observer acceptance of computer-defined borders was estimated at 94%, 93%, and 97% for excellent, good, and poor quality studies, respectively. Once the observer defined a region of search, computer process time to generate all borders in the cardiac cycle was approximately 4 minutes. The conclusion is that the algorithm produces accurate, reliable, and acceptable borders.

Algorithms↗
PubMedDate not supplied

The case for echocardiography in acute myocardial infarction.

Acute myocardial infarction occurs after a period of profound myocardial ischemia. Ischemia of this degree immediately produces a regional contraction abnormality, which is readily detectable by echocardiography before the onset of necrosis. Echocardiography has been used both experimentally and clinically as a guide to the functional extent of myocardial involvement in evolving infarction and hence provides an objective anatomic basis for electing therapeutic interventions and assessing a prognosis.

Animals↗
PubMedDate not supplied

Topographic correspondence of contrast echocardiographic perfusion mapping and myocardial infarct extent after varying durations of coronary occlusion.

After acute coronary occlusion, the extent of dysfunction exceeds the extent of infarction by a variable amount. Contrast echocardiography has been shown to be a good predictor of the extent of acute infarction after permanent occlusion. We used hydrogen peroxide contrast echocardiography to study the temporal and topographic relationship between contrast enhancement and tissue viability during acute myocardial infarction in 32 dogs undergoing 1, 2, 3, or 4 hours of circumflex occlusion before reperfusion. To account for changes in collateral blood flow, contrast studies were performed by aortic root injection immediately before reperfusion. The area, circumference, and transmural extent of the region at risk in vivo by contrast echocardiography were statistically unchanged regardless of the duration of occlusion before reperfusion. Echo contrast defect analysis of the risk region predicted the area, circumference, and transmural extent of infarcts reperfused at 2 or more hours (r = 0.81, 0.84, 0.71, respectively). For the 1-hour occlusion group, contrast defect analysis predicted the circumference at risk but markedly overestimated the area and transmural extent of infarction. These data indicate that the circumferential extent of infarction can be identified by contrast echo and is fixed by 1 hour of occlusion. Infarction progression transmurally within the circumferential boundaries had nearly reached the transmural contrast extent by 2 hours of occlusion in this model. Assuming the development of a similar high contrast agent safe for human injection, aortic root contrast echocardiography could be useful to predict myocardium at risk of infarction early after occlusion. Late after occlusion it could be of value to predict the presence of still viable myocardial layers within the dysfunctional infarct region.

Animals↗
PubMedDate not supplied

Quantifying changes in regional myocardial perfusion with aortic contrast echocardiography.

We developed a technique to assess regional myocardial perfusion by quantifying echocardiographic myocardial contrast appearance and intensity after aortic root injection of an agitated diatrizoate meglumine solution. The technique was validated by comparing digitized echocardiographic contrast parameters to regional perfusion in the circumflex bed determined by calibrated Doppler flow probe and antemortem monastral blue staining. Regional perfusion was altered by circumflex stenosis, occlusion, and reactive hyperemia. Contrast effects were measured in an initial subset of six dogs by peak intensity change, time to peak intensity, maximal rate of intensity rise, and mean intensity change integrated over 1, 2, or 3 seconds after contrast appearance (MI1, MI2, MI3). MI2 and MI3 best predicted regional perfusion (r = 0.93, standard error of the estimate [SEE] 0.38 ml/gm/min for each). These findings were confirmed in a second subset of six dogs (r = 0.84, SEE = 0.70 ml/gm/min). Although there was a relatively broad standard error for the prediction of absolute perfusion for the pooled data, for individual dogs data were internally consistent so that each had r greater than 0.88 for its varied flow states. The hyperemic ratio calculated by contrast echocardiography correlated well with the Doppler value (r = 0.85). Observer and study-to-study predictive variabilities were small (SEE 0.19 to 0.32 ml/gm/min). No alterations were seen in hemodynamics or reactive hyperemia after 25 consecutive injections over a 90-minute period. Contrast echocardiography with aortic root contrast injection tracks changes in regional blood flow. This approach can assess regional coronary reserve and detect changes in regional myocardial perfusion during acute ischemia and drug intervention.

Animals↗
PubMedDate not supplied

Systolic time intervals in hypothyroidism: end organ function as a reflection of clinical status.

Systolic time intervals (STI) were determined in 14 hypothyroid patients who did not have congestive heart failure or atrial fibrillation, and who were not taking cardiotropic drugs. Compared to normals, there was a significant decrease in the left ventricular ejection time (LVET) and there were significant increases in the pre-ejection period (PEP) and the PEP/LVET ratio. The prolongation of the PEP primarily reflected lengthening of the isovolumic contraction time. Serial recordings during thyroxine therapy in seven patients showed consistent changes in STI toward normal values. These results in hypothyroid patients complement our earlier data in hyperthyroid patients; they indicate that STI's are a sensitive measure of the heart as an end organ over the entire range of thyroid hormonal activity.

Adult↗
PubMedDate not supplied

A system for quantitative evaluation of left ventricular function with two-dimensional ultrasonography.

Phased-array ultrasonic imaging systems produce real-time sectional images of the left ventricle. To quantify left ventricular function, a light-pen-based system was developed using a minicomputer to analyze the geometry of ultrasound images and measure left ventricular volume, ejection fraction, and regional contraction. System accuracy was evaluated by comparing measurements abtained from left ventricular cineangiograms at cardiac catheterization on a series of 25 patients to echocardiographic left ventricular long- and short-axis linear dimensions (r = 0.92, S.E.E. = 0.67 cm), end-diastolic volume (r = 0.84, S.E.E. = 45 cm3), and ejection fraction (r = 0.80, S.E.E. = 0.10). Five patients from the study population with electrocardiographically documented transmural myocardial infarcts had regional contraction abnormalities detected by this analytic approach. Quantitative application of two-dimensional echocardiography appears to be a useful noninvasive method of evaluating left ventricular ejection fraction and has potential to define regional contraction abnormalities objectively.

Cardiac Output↗