The index of myocardial performance and aortic regurgitation: the influence of a volume overload lesion.

OBJECTIVE

The index of myocardial performance (IMP) is a global cardiac function index with prognostic utility in patients with myocardial infarction and dilated cardiomyopathy but is preload dependent. We hypothesized that a volume overload lesion prolonging LV ejection time (LVET) may reduce IMP despite LV dysfunction (LVD).

METHODS

The study groups consisted of 35 normals, 26 with LV dysfunction, and 60 with aortic regurgitation (AR): 40 with ejection fraction (EF) >50% (AR+Normal EF) and 20 with ejection fraction > or = 50% (AR+Reduced EF). We evaluated consecutive patients in each group with technically adequate 2D and Doppler echocardiography.

RESULTS

When compared to normal subjects (0.357+/-0.122), IMP was increased with LVD (0.604+/-0.278 p<0.001) but was similar in AR+Normal EF patients due to isovolumic relaxation time (IRT) and LVET prolongation. The IMP was lower in AR+Reduced EF group (0.346+/-0.172, p<0.001) as compared to the LVD group due to a prolonged LVET and a reduced IRT and isovolumic contraction time (ICT).

CONCLUSIONS

The IMP in AR+Normal EF patients was similar to normals due to IRT and LVET prolongation. The IMP was reduced in AR+Reduced EF patients compared to LVD patients due to IRT and ICT shortening and LVET prolongation. The index of myocardial performance in AR patients should be applied with caution.