Do False Tendons Prevent Adverse Left Ventricular Remodeling After Anterior Wall Myocardial Infarction? An Echocardiographic Strain Imaging Study

Abstract

The role of muscular left ventricular (LV) false tendons (FTs) is poorly understood. To gain insight into their pathophysiologic significance, we adapted echocardiographic LV strain imaging software to measure LVFT longitudinal strain in subjects with normal left ventricles and in patients who sustained previous anterior wall myocardial infarction (AWMI). GE EchoPAC software was used to measure longitudinal strain in LVFTs ≥0.3 cm in diameter. Tendinous strain was measured in 11 patients with LVFTs confined to the left anterior descending artery territory (connecting the anteroseptum or anterior wall to the apex) ≥6 months after AWMI (myocardial infarction [MI]+FT+ group) and in 25 patients with normal hearts containing LVFTs (MI-FT+ group). We also compared the indexed LV end-diastolic volumes in the MI+FT+ group to that of 25 patients with previous AWMI without LVFTs (MI+FT- group). The mean LVFT strain in MI+FT+ group was 5.5 ± 6.2% and -28.9 ± 4.7% in the MI-FT+ group (p <0.0001). The indexed LV end-diastolic volume in the MI+FT+ group did not differ from the MI+FT- group (88.4 ± 17.8 vs 87.9 ± 17 ml/m², p = 0.90). In conclusion, the negative strain (contraction) developed by LVFTs in the MI-FT+ group may help maintain normal LV size and shape by generating inward restraining forces. The development of positive strain (stretch) in LVFTs in patients in the MI+FT+ group suggests they become infarcted after AWMI. This implies that they are incapable of generating inward restraining forces that might otherwise mitigate adverse remodeling. Of note, LV volumes after AWMI do not differ whether or not LVFTs are present.

Keywords: left ventricular false tendons; left ventricular remodeling; longitudinal strain; myocardial infarction.