Objectives The aim of this study was to evaluate the changes of myocardial strain Rate and Aneurysm volume and the effect of left ventricular aneurysm (LVA) volume and myocardial strain on left ventricular function in a rabbit model using real time three-dimensional echocardiographic imaging (RT-3DE) combined with two-dimensional speckle-tracking imaging (2D-STI).
Methods A rabbit model of LVA was prepared in 30 New Zealand rabbits by ligating the middle segment of the left anterior descending artery and the left circumflex artery (LVA group); 10 control rabbits underwent thoracotomy alone. Four weeks later, RT-3DE was performed to obtain data on left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), and LVA volume. The peak short-axis radial (SrR) and circumferential (SrC) strain rates were measured using 2D-STI technique.
Results Compared with control rabbits, LVA group rabbits had significant left ventricular enlargement at the end-systolic and end-diastolic phases (both P < 0.05). LVEF, SrR-Systolic, and SrC-Systolic were significantly lower in the LVA group (all P < 0.05). Moreover, there were high correlations between LVEF and SrC-Systolicanterior wall, SrR-Systolicanterior wall, SrC-Systoliclateral wall, and SrR-Systoliclateral wall (r = 0.895, 0.887, 0.890, 0.891, respectively, all P < 0.05). Of note, LVA volume/LVEDV had the tightest inverse relationship with LVEF (r = -0.911, P < 0.01). Specifically, LVA volume/LVEDV >16% corresponded to LVEF <50%, and LVEF decreased 1.1% while LVA volume/LVEDV increased 1%.
Conclusions LVA volume/LVEDV provided a sensitive indicator reflecting cardiac function with LVA. Measurement of various parameters using RT-3DE might be a useful means to evaluate cardiac function after LVA formation.