Predominant inner-half wall thickening of left ventricle is attenuated in dilated cardiomyopathy: An application of tissue Doppler tracking technique

The importance of the inner half (IH) of the left ventricular (LV) wall has been reported in hearts that contract normally. However, it is difficult t o verify this fact in an in vivo human heart with clinical echocardiography . By using a recently developed tissue Doppler tracking technique, we could assess the systolic wall thickening of the IH and outer half (OH) of the L V wall in 11 normal and 7 dilated cardiomyopathic hearts. Percent wall thic kening and the fractional contribution of the IH and OH to the transmural w all thickening were calculated. In healthy subjects, percent wall thickenin g of the IH, OH, and transmural wall of the left ventricle were 75.8% +/- 2 4.1%, 39.4% +/- 14.4% (P < .001 versus IH), and 57.6% +/- 17.6%, respective ly. In patients with dilated cardiomyopathy, those values were 31.3% +/- 17 .1%, 31.2% +/- 20.1% (not significant versus IH), and 31.2% +/- 16.5%, resp ectively. On the other hand, the fractional contributions of the IH and OH were 66.2% +/- 7.7% and 33.8% +/- 7.7% (P < .01 versus IH) in healthy subje cts and 50.5% +/- 11.8% and 49.5% +/- 11.8% (not significant versus IH) in patients with dilated cardiomyopathy. Specifically, the M contributed to th e transmural wall thickening nearly twice as much as the OH did in healthy subjects, however, the predominance of IH contribution was attenuated in di lated cardiomyopathy. The tissue Doppler tracking technique is useful in as sessing the IH and OH LV wall thickening separately in the clinical situati on.