Echocardiographic determination of contraction and relaxation measurements of the left ventricular wall in normal subjects and patients with muscular dystrophy.

Abstract

Boys with Duchenne's muscular dystrophy (DMD) usually have a cardiomyopathy characterized by fibrosis of the epicardial half of the left ventricle. This cardiomyopathy is difficult to detect by noninvasive techniques. We report a technique that evaluates incremental left ventricular posterior wall thickening and thinning. High-quality left ventricular posterior wall echoes in 24 boys with DMD and 32 controls were recorded at chordal level two times 1 year apart. Endocardial and epicardial echoes and a timing ECG were digitized and analyzed by minicomputer. Left ventricular wall amplitudes were determined at standardized temporal increments during contraction and relaxation. To compare with this left ventricular assessment technique, systolic ejection times, shortening fraction and mean velocity of circumferenial fiber shortening (Vcf) were also computed in the standard way. Mean year-to-year changes were minor. Mean Vcf, the ratio of preejection period to left ventricular ejection time and shortening fraction during the first year were statistically similar to those of the controls. Shortening fraction decreased slightly during the second year and became significantly different from the control, but remained within the normal range. Left ventricular wall thickness and cavity size were significantly less in boys with DMD than in controls. Therefore, we had to normalize incremental wall thickness to determine if any significant difference occurred. To do this, we evaluated the percentage of maximal wall thickness which occurred at a given percent of systole and diastole. Using this technique, it was shown that thickening during systole was a nearly linear process with respect to time in both groups. However, relaxation was significantly different between the groups. Relaxation was found to be an alinear process, and most thinning occurred in the first 40% of diastole. The major findings of this investigation was that the left ventricular wall of boys with DMD thinned at a slower rate than that of normal subjects. This new technique appears to be sensitive and demonstrates subtle changes in the left ventricular posterior wall.

X-Chromosomal (p21) Muscular Dystrophy and Left Ventricular Diastolic and Systolic Function

“…Mean age of the patients was 15.5 years (range [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Nine patients had Duchenne muscular dystrophy (DMD) and 6 patients had Becker muscular dystrophy (BMD).…”

Left ventricular function in beta thalassaemia major.

“…Group 2 comprised 32 children with homozygous 13 thalassaemia who needed regular blood transfusion; none had clinical evidence of heart failure and at the time of study none was on iron chelation treatment. In the follow up period, 27 in group 2 remained well but five developed overt congestive heart failure and died within 12 (5) end diastolic wall thickness, (6) end systolic wall thickness, and (7) wall fractional thickening (end systolic wall thickness/end diastolic wall thickness)-1.…”

Global and Segmental Left Ventricular Function in β-Thalassemia

“…LV expected dimen sions (Dd and Ds) and thickness (IVS and LVPW) were computed for each individual patient in relation to age and body surface area [ 15] and the percent dif ference (% A) from the actual measurements was cal culated. Tracings of the expanded LVPW were ana lyzed and measured according to the method of Gold berg et al [8], LVPW thickness was measured at 25. 50, 75, 100% of the systole and at 10, 20, 40, 60, 100% of the diastole, and the percentage thickening and thinning was calculated for each timepoint.…”

“…To augment the sensitivity of all conventional global LV systolic and diastolic indices, apart from using a large number of them additionally, we applied the method of Goldberg et al [8] for the evaluation of seg mental LV function.…”