Objective: To dynamically evaluate left ventricular perfusion, global and local functional changes during left ventricular aneurysm (LVA) formation and to explore the relationship between the size of LVA and LVEF, LVESV, LVEDV by gated99mTc-MIBI SPECT (GSPECT) and gated18F-FDG PET metabolic (GPET) imaging in experimental pigs. Methods: LVA model was established by occlusion of left circumlfex artery (LCX) and placing an Ameroid constrictor at the proximal end of left anterior descending artery (LAD) in a total of 16 Chinese mini-pigs. At the 1st, 4th and 8th weeks of surgery, the changes of total perfusion defect (TPD), LVA formation and LVEF, LVESV, LVEDV were dynamically evaluated by GSPECT and GPET; the relationships between the size of LVA and LVEF, LVESV, LVEDV were analyzed respectively.Results: There were 5 pigs died in surgery and 2 died at the 1st week of modeling. According to golden (pathological) standard, 9 animals successfully ifnished the dynamic imaging study. At the 1st week of (basic) modeling, 4 animals formed large LVA, 2 formed small LVA at the apex and 3 without LVA formation. At the 4th and 8th weeks of modeling, dynamic imaging presented that the animals with large LVA had gradually increased range and degree of perfusion defect, LVEDV, LVESV, while gradually decreased LVEF; the above indexes were relatively stable in animals with small or none LVA. In addition, the size of LVA was related to LVEF (r=-7.26), LVEDV (r=0.855) and LVESV (r=0.825), allP<0.05. Conclusion: In experimental pigs, at the beginning of LVA formation, large range and severe perfusion defect may cause large aneurysm, the LV functional damage and remodeling may gradually increase and the prognosis is poor; in contrast, the animals with small or none LVA have better prognosis and usually without ventricular remodeling; which implies that in acute phase of LVA formation, the size of aneurysm may predict the trend of global LV systolic function and remodeling at the early stage.

Objective: To assess the impact of viable myocardium in left ventricular aneurysm (LVA) and ventricular arrhythmia on prognosis of LVA patients.
Methods: A total of one hundred and sixty LVA patients who received99Tcm-MIBI SPECT and18F-FDG PET were enrolled, including 139 male and 21 female with the mean age of (58 ± 10) years.There were 42 (26.3%) patients combining ventricular arrhythmia. LVEDV, LVESV and LVEF were detected. Semi-quantitative analysis of myocardium perfusion imaging was conducted, viable myocardium in aneurysm was deifned as the perfusion-metabolism mismatch score (MMS) ≥ 2.0. According to myocardium viability, the patients were divided into 2 groups: No viability group,n=97 and With viability group,n=63;based on ventricular arrhythmia, the patients were divided into another 4 groups: Group①, viability-, ventricular arrhythmia-, n=68, Group②, viability-, ventricular arrhythmias+,n=29, Group③, viability+, ventricular arrhythmias-,n=50 and Group④, viability+,ventricular arrhythmias+,n=13. The average follow-up time was (50 ± 7) months, the end point was cardiac death. The survival curve was obtained by Kaplan-Meier method and survival rates were compared by Log-rank analysis.
Results: The mean LVEF in 160 patients was (34 ± 11) %, cardiac death occurred in 19 (11.9%) patients. Long-term survival rates in Groups①,② and③ were 94.1%, 89.7% and 86.0%, respectively,P>0.05; while in Group④, the survival rate was 61.5%, which was lower than the other 3 groups,P=0.004. Multivariate Cox regression analysis showed that female (HR=5.101, 95% CI 1.853-14.044, P=0.002), GPET-ESV (HR=1.009, 95% CI 1.002-1.015,P=0.013), interaction between MMS and ventricular arrhythmia (HR=1.368, 95%CI 1.113-1.681,P=0.003) were independent risk factors for cardiac death;while surgical treatment (HR=0.199, 95% CI 0.054-0.742,P=0.016) could decrease the risk of cardiac death.
Conclusion: Patients with viable aneurysm and ventricular arrhythmia had poor long-term prognosis; while early and active treatment is needed for them (surgery with anti-arrhythmic therapy).