Influence of preload alterations on parameters of systolic left ventricular long-axis function: a Doppler tissue study.

The study examined the influence of preload alterations on parameters of left ventricular (LV) long-axis function during systole. Doppler tissue echocardiography was performed in 32 healthy volunteers at rest who were placed in the Trendelenburg position after administration of 0.8 mg of nitroglycerin sublingually. In a 16-segment LV model, long-axis myocardial strain and systolic velocities were assessed. Isovolumic acceleration was assessed in the lateral mitral annulus. Mean LV strain and systolic velocity were unchanged during the different load conditions. In the mitral annulus, strain was also uninfluenced by preload alterations, whereas the peak systolic velocities seemed influenced by preload reduction. The isovolumic acceleration of the mitral annulus was found to be load dependent (enhanced preload 1.38 +/- 0.50 vs baseline 1.6 m/s2 +/- 0.60, P <.01; and preload reduction 2.18 +/- 0.65 m/s2, P <.01). In conclusion, LV long-axis strain and systolic velocities were not significantly influenced by load alterations, whereas myocardial systolic velocities and isovolumic acceleration in the lateral mitral annulus were significantly load dependent.