Stress-induced changes in subendocardial tissue texture in hypertrophic cardiomyopathy: an echocardiographic videodensitometric study.

BACKGROUND

Myocardial ischemia changes myocardial acoustic properties, inducing increase of integrated backscatter and blunting of cyclic variation of backscatter. Stress-induced subendocardial underperfusion has been demonstrated in patients with hypertrophic cardiomyopathy (HCM).

AIM

To evaluate the potential of a videodensitometric approach in assessing transmural ultrasonic tissue changes in HCM during dipyridamole infusion.

METHODS

Twenty-two patients (13 males, 50+/-12 years) with HCM underwent dipyridamole echo testing (DET). Myocardial gray levels amplitude was calculated off-line on digitized images in the left subendocardial (LV-endo), right subendocardial (RV-endo) region of the interventricular septum and posterior wall (long axis parasternal view).

RESULTS

The thickness of the interventricular septum and posterior wall was 1.9+/-0.3 and 1.17+/-2.1 cm, respectively. In the LV-endo layer, the cyclic variation was blunted during DET (rest = 37+/-14 vs. DET 27+/-20%, p < 0.02). In the RV-endo layer and posterior wall, no changes occurred. In the LV-endo layer of the septum, blunting of cyclic variation was more pronounced in the 10 patients with than in the 12 without ST-segment depression during DET (21.2+/-14.7% vs. 43.8+/-15.8, p < 0.01).

CONCLUSIONS

In HCM patients, DET induced blunting of cyclic variation without the evidence of wall motion abnormalities. This reduction was more pronounced when electrocardiographic signs of ischemia were simultaneously elicited by DET.