A videodensitometric study of transmural heterogeneity of cyclic echo amplitude variation in human myocardium

The aims of this study were: (1) to assess whether variations in cyclic echo amplitude might be detected across the human myocardium by videodensitometric analysis of images obtained with epicardial echocardiography; and (2) to explore the possible relation between cyclic gray level variation and left ventricular [LV) hypertrophy and function. Experimental studies show that transmural differences in contractile performance across the normal myocardium are paralleled by differences in the cyclic (diastolic-to-systolic) variation of myocardial echo amplitude, Thirty-three patients (aged 60 +/- 11 years) undergoing cardiac surgery were studied by intraoperative epicardial echocardiography. LV mass index was normal (< 110 g/m(2) in women, < 131 g/m(2) in men) in 10 patients and increased in 22. Two-dimensional echocardiographic images were obtained with a 5 MHz transducer and digitized off-line. Videodensitometric analysis was performed at end-diastole and end-systole with regions of interest across the septal and posterior wall, The cyclic variation was more pronounced in the left than in the right septal subendocardium (31% +/- 14% vs 16% +/- 14%, p < 0.01) and higher in the subendocardial than in the subepicardial layer of the posterior wall (30% +/- 21% vs 23 +/- 18%, p < 0.01). Cyclic variation of the left septal subendocardium wets higher in 11 patients with nonhypertrophic ventricles than in 22 with hypertrophic left ventricles (42% +/- 15% vs 27% +/- 12%; p < 0.01). The percent cyclic variation of the left septal subendocardium appeared to be much more tightly related to percent systolic thickening in patients with eccentric LV hypertrophy (r = 0.80 p < 0.01) than in patients with concentric LV hypertrophy (r = 0.27, p = 0.9) or normal LV mass (r = 0.43, p = 0.2).