Jean G. Nelson

Accurate noninvasive quantification of stenotic aortic valve area by Doppler echocardiography.

Laminar flow through a conduit is equal to the mean velocity times the cross-sectional area of the orifice. Therefore, volume is equal to the time-velocity integral multiplied by the cross-sectional area. In aortic stenosis, flow in the stenotic jet is laminar and the aortic valve area should be equal to the volume of blood ejected through the valve divided by the time-velocity integral of the aortic jet velocity recorded by continuous-wave Doppler echocardiography. To test whether this concept can be used to accurately determine aortic valve area noninvasively by the Doppler method, 39 patients (age 35 to 82 years, mean 63) underwent pulsed Doppler combined with two-dimensional echocardiography for measurement of stroke volume at the aortic, pulmonic, and mitral anulus as well as continuous-wave Doppler recording of the aortic jet. Aortic valve area determined at cardiac catheterization by the Gorlin equation ranged between 0.4 and 2.07 cm2 (mean 0.89 +/- 0.45). Doppler-derived valve area, determined with the stroke volume value from either the aortic, pulmonic, or mitral anulus, correlated well with the area determined at cardiac catheterization (r = .95, .97, and .96, respectively). A simplified method for measuring aortic valve area derived as the cross-sectional area of the aortic anulus times peak velocity just proximal to the aortic valve divided by peak aortic jet velocity correlated well with measurements obtained at cardiac catheterization (r = .94). An excellent separation between critical and noncritical aortic stenosis was seen using either one of the Doppler methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of preoperative hypertrophy, wall stress and end-systolic dimension as echocardiographic predictors of normalization of left ventricular dilatation after valve replacement in chronic aortic insufficiency

To define and compare predictors of postoperative normalization of diastolic left ventricular dimension after aortic valve replacement, echocardiographic indexes of left ventricular size, function, degree of hypertrophy and systolic wall stress were examined in 43 patients with chronic and 14 with acute aortic insufficiency. In all of the latter 14 patients, left ventricular diastolic dimension returned to normal (mean 5.2 +/- 0.4 cm) in the postoperative follow-up period (mean 8.0 months). In contrast, of those with chronic insufficiency, 28 (group A) had postoperative normalization of diastolic dimension whereas the remaining 15 (group B) had persistent enlarged diastolic dimension. Preoperative end-systolic dimension, diastolic radius/thickness ratio, mean radius/thickness ratio, mean wall stress and end-systolic stress were 84 to 93 percent accurate in predicting normalization versus persistence of left ventricular dilatation postoperatively, and were superior to preoperative end-diastolic dimension and shortening fraction. Postoperatively, group A had complete normalization of end-systolic dimension and of mean and end-systolic wall stresses with persistence of a normal shortening fraction. Group B continued to have increases in end-systolic dimension, mean wall stress and end-systolic stress with a reduction in shortening fraction. Postoperatively there was a 43 and 29 percent incidence rate of heart failure and death by heart failure, respectively, in group B versus none in group A (p less than 0.01). These findings support the concept that inappropriate hypertrophy in chronic aortic insufficiency is associated with progressive increases in wall stress and end-systolic dimension and a reduction in shortening fraction that eventually result in irreversible cardiac dilatation and failure. Accurate and clinically relevant determination of reversible and irreversible alterations in left ventricular size and function may be obtained with these echocardiographic indexes.

Comparison of two-dimensional echocardiography with gated radionuclide ventriculography in the evaluation of global and regional left ventricular function in acute myocardial infarction

Two-dimensional echocardiography and gated radionuclide ventriculography were performed in 93 patients (66 men, 27 women; mean age 61 years) with 95 episodes of acute myocardial infarction within 48 hours and at 10 days after infarction. Electrocardiographic sites of infarction were: 35 anterior, 49 inferoposterior and 11 nonlocalized. Abnormal motion of the anterior wall, septum or apex was seen in 97 and 100% of anterior infarctions by radionuclide ventriculography and echocardiography, respectively. Abnormal motion of an inferior or posterior wall segment was seen in 91% of inferoposterior infarctions by echocardiography versus 61% seen by radionuclide ventriculography. Ejection fractions determined by echocardiography and radionuclide ventriculography correlated well (r = 0.82) and did not change from the first 48 hours to 10 days after infarction (0.48 +/- 0.14). Similarly, wall motion score showed minimal change from the first 48 hours to 10 days. In-hospital mortality was 37 and 42% in patients with an ejection fraction of 0.35 or less by echocardiography and radionuclide ventriculography, respectively. No mortality was seen in patients with an ejection fraction above 0.40 by either test. The echocardiographic wall motion score was also predictive of mortality (40 versus 2%; score less than or equal to 0.50 versus greater than 0.50). The 1 year mortality rate in the 81 short-term survivors was 17%. Mortality was lowest in patients with an ejection fraction above 0.49 or wall motion score above (0.79 (2 to 5%) and worse in those with an ejection fraction below 0.36 or wall motion score below 0.51 (36 to 63%) by either technique. Thus in acute myocardial infarction, echocardiography and radionuclide ventriculography provide a comparable assessment of left ventricular function and wall motion in anterior infarction. Echocardiography appears more sensitive in detecting inferoposterior wall motion abnormalities. Both techniques are capable of identifying subgroups of patients with a high risk of death during the acute event and with an equally high mortality rate over a 1 year follow-up period.

Effect of cardiac surgery on ventricular septal motion: Assessment by intraoperative echocardiography and cross-sectional two-dimensional echocardiography

Echocardiographic evidence of paradoxical septal motion frequently occurs after cardiac surgery. To assess possible etiologic factors 17 patients were studied preoperatively, intraoperatively, and 7 days after surgery. Preoperative septal motion was normal in 14 and paradoxical in three (two with previous cardiac surgery, one with atrial septal defect [ASD]). Intraoperative septal motion prior to surgical procedure was normal in 16 and paradoxical in one (ASD). Septal motion (excursion and thickening fraction) was normal in all patients prior to chest closure. Echocardiograms of adequate quality were obtained at 7 days post surgery in 15 patients; septal motion was paradoxical in nine (group A) and normal in six (group B). No significant differences were seen between the two groups in ischemic time or in the preoperative to postoperative change in left ventricular (LV) and right ventricular diastolic dimension, shortening fraction, or septal and posterior wall thickening fraction. A significant postoperative decrease in septal excursion was seen in group A but not in group B; significant postoperative increases in posterior wall excursion were seen in both groups. Cross-sectional two-dimensional echocardiograms performed in 20 patients (8 normal, 12 postoperative paradoxical septal motion) were analyzed. In normal controls no significant change was detected in the LV centroid position during systole. In contrast, the 12 postoperative patients showed significant anterior displacement of the LV centroid and right septum during systole. Thus, paradoxical septal motion after cardiac surgery appears to relate to excessive anterior cardiac mobility due to pericardiotomy rather than to myocardial ischemia resulting from cardiopulmonary bypass.

Cardiac echinococcal cyst: Diagnosis by two-dimensional echocardiography

A case of an intracardiac echinococcal cyst is presented. The diagnosis was made by two-dimensional echocardiography, which clearly identified a large multiseptated cystic structure in the right ventricular outflow tract. The findings were verified at surgery. It is suggested that two-dimensional echocardiography may be the procedure of choice in the diagnosis of cardiac echinococcal disease.

Mid systolic closure of aortic valve in hypertrophic cardiomyopathy: Echocardiographic and angiographic correlation

Abstract To compare the reliability of the mid systolic closure of the aortic valve with asymmetric septal hypertrophy and systolic anterior motion of the mitral valve in predicting left ventricular outflow obstruction in hypertrophic cardiomyopathy, 15 patients with this clinical diagnosis and echocardiographic findings of asymmetric septal hypertrophy and systolic anterior motion of the mitral valve were studied. Of these, six (40 percent) had mid systolic closure of the aortic valve. All six patients had evidence of an intraventricular pressure gradient and angiographic findings confirming the presence of left ventricular outflow obstruction. Of the nine remaining patients, six (67 percent) had an intraventricular pressure gradient, whereas three (33 percent) had no demonstrable gradient. Of the six patients with a gradient and no mid systolic valve closure, only two had definite angiographic evidence of outflow obstruction; in the remaining four patients the gradient could be accounted for by the finding of left ventricular cavity obliteration. Among the total group of 15 patients, angiographic evidence of outflow obstruction was found in 8 (53 percent), whereas 7 (47 percent) had left ventricular cavity obliteration; these included the 3 patients with no intraventricular gradient. Of the eight patients with angiographic evidence of outflow obstruction, six (75 percent) had the echocardiographic finding of mid systolic closure of the aortic valve. Thus, although the incidence of mid systolic closure of the aortic valve in hypertrophic cardiomyopathy is relatively low, this finding appears to be a moderately sensitive sign of left ventricular outflow obstruction and may be a more specific predictor of outflow obstruction than asymmetric septal hypertrophy and systolic anterior motion of the mitral valve.