Integrated ultrasonic backscatter (IB) is a noninvasive measure of the acoustic properties of myocardium. Previous experimental studies have indicated that altered acoustic properties of the myocardium are reflected by the magnitude of variation of IB during the cardiac cycle. In our study, cardiac cycle-dependent variation of IB was noninvasively measured using a quantitative IB imaging system in 12 patients with uncomplicated pressure-overload hypertrophy and 13 patients with hypertrophic cardiomyopathy. Sixteen normal subjects served as a control. The magnitude of cardiac cycle-dependent variation of IB for the posterior wall was 6.0± 0.9 dB in normal subjects, 5.7±+0.8 dB in the patients with uncomplicated pressureoverload hypertrophy, and 6.7+±2.1 dB in the patients with hypertrophic cardiomyopathy. There were no significant differences among any of these groups. In contrast, the magnitude of cardiac cycle-dependent variation of IB for the septum was significantly smaller in the patients with uncomplicated pressure-overload hypertrophy (2.8+1.3 dB) and in the patients with hypertrophic cardiomyopathy (3.1±2.3 dB) than in normal subjects (4.9±1.0 dB). The magnitude of cardiac cycle-dependent variation of IB was smaller as the wall-thickness index increased (r=-0.53, p<0.01, n=82 for all data). This IB measure also correlated with percent-systolic thickening of the myocardium (r=0.67,p<0.01, n=82). Thus, alteration in the magnitude of cardiac cycle-dependent variation of IB was observed in hypertrophic hearts and showed apparent regional myocardial differences. (Circulation 1989;80:925-934) L eft ventricular hypertrophy is a common adaptation mechanism in patients with pressure overload such as hypertension and aortic stenosis.1,2 Idiopathic left ventricular hypertrophy also may occur and this is usually classified as hypertrophic cardiomyopathy (HCM).3 HCM, in most cases, is characterized by asymmetric septal hypertrophy,4-8 and, thus, M-mode and twodimensional echocardiography are useful both in the quantification of hypertrophy and in the differentiation of these two forms of hypertrophy.

To study the three-dimensional size, shape, and motion of the mitral leaflets and annulus, we surgically attached radiopaque markers to sites on the mitral annulus and leaflets in seven sheep. After 8 days of recovery, the animals were sedated, and three-dimensional marker positions were measured by computer analysis of biplane videofluorograms (60/s). We found that the oval mitral annulus became most elliptical in middiastole. Both leaflets began to descend into the left ventricle (LV) during the rapid fall of LV pressure (LVP), before leaflet edge separation. The anterior leaflet exhibited a compound curvature in systole and maintained this shape during opening. The central cusp of the posterior leaflet was curved slightly concave to the LV during opening. Markers at the border of the “rough zone” were separated by 10 mm during systole. We conclude that coaptation occurs very near the leaflet edges, that the annulus and leaflets move toward their open positions during the rapid fall of LVP, and that leaflet edge separation, the last event in the opening sequence, occurs near the time of minimum LVP.

To determine the value of transesophageal ultrasound in the assessment of cardiac valve prostheses, 14 patients with clinically suspected mitral prosthesis malfunction were studied by transthoracic and transesophageal two-dimensional imaging as well as by color Doppler flow velocity mapping (color Doppler). Patients underwent left ventricular angiography (n = 13), surgery (n =11), or both angiography and surgery (n = 10). Nine patients had only mitral valve replacement, four patients had both mitral and aortic valve replacement, and one patient had mitral, aortic, and tricuspid valve replacement. There were 16 biological and four mechanical prostheses. The degree of mitral regurgitation was graded by both transthoracic and transesophageal color Doppler according to the area of the regurgitant jet visualized and was compared with a three-point classification of mitral regurgitation by left ventricular angiography judged by observers blinded to the echocardiographic results. All transesophageal studies were performed without complication and were well tolerated. The pathological morphology of the mitral prosthesis was additionally or more clearly visualized by transesophageal twodimensional imaging and subsequently proven at surgery in three patients with flail leaflets and one patient with a vegetation compared with images obtained by the transthoracic approach. Valvular regurgitation was graded by the transthoracic approach as absent in four patients, mild in two patients, moderate in five patients, and severe in only three patients. The transesophageal assessment showed absence of mitral regurgitation in two patients, moderate regurgitation in two patients, and severe regurgitation in 10 patients. Left ventricular angiography done in 13 of the 14 patients revealed no regurgitation in two patients, mild regurgitation in one patient, moderate regurgitation in one patient, and severe mitral regurgitation in nine patients. This corresponded to the grading by transesophageal echocardiography in 12 of the 13 patients with the 13th patient graded as mild regurgitation by angiography and moderate regurgitation by transesophageal echocardiography. We conclude that in patients with biological mitral prosthesis malfunction, transesophageal two-dimensional imaging, as well as color Doppler, can provide reliable diagnostic information beyond that available from the transthoracic approach with the degree of mitral regurgitation corresponding to that found on left ventricular angiography. (Circulation 1988;78:848-855) TNhe potential value of transthoracic twoeven with advanced ultrasound equipment in obese dimensional and Doppler echocardiography and emphysematous patients, as well as in patients in the assessment of prosthetic heart valves with chest deformities and in the early postoperahas been well established. [1][2][3][4] However, accurate tive period. Even in apparently high-quality recorddiagnosis of prosthesis malfunction may be difficult ings, the ultrasound beam is attenuated by the material of most prostheses.5...

Experimental studies have shown that variation in the magnitude of integrated ultrasonic backscatter during the cardiac cycle represents acoustic properties of myocardium that are affected by pathologic processes; however, there are few clinical studies using integrated backscatter. Forty subjects without cardiovascular disease (aged 22 to 71 years, mean 41) were studied with use of a new M-mode format integrated backscatter imaging system to characterize the range of cyclic variation of integrated backscatter in normal subjects. Cyclic variation in integrated backscatter was noted in both the septum and the posterior wall in all subjects. The magnitude of the cyclic variation of integrated backscatter and the interval from the onset of the QRS wave of the electrocardiogram to the minimal integrated backscatter value were measured using an area of interest of variable size for integrated backscatter sampling and a software resident in the ultrasound scanner. The magnitude of cyclic variation was larger for the posterior wall than for the septum (6.3 +/- 0.8 versus 4.9 +/- 1.3 dB, p less than 0.01). The interval to the minimal integrated backscatter value was 328 +/- 58 ms for the septum and 348 +/- 42 ms for the posterior wall (p = NS). There was a weak correlation between the magnitude of cyclic variation of integrated backscatter and subject age for the posterior wall (r = -0.47, p less than 0.01), but this was not significant for the septum (r = -0.21) (partially because of inability to exclude specular septal echoes) and septal endocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

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