Left Heart Ejection Fraction as a Load-Independent Parameter for Patients with Mitral Regurgitation

The functions of the left ventricle and left atrium are closely associated with the outcomes of surgically treated patients with severe mitral regurgitation (MR). However, both parameters were overestimated in the presence of MR. The present study integrated the left atrium and left ventricle as the left heart (LH) to eliminate the influence of MR within the integrated structure. The study aim was to explore whether the emptying fraction of the LH is a load-independent parameter for patients with MR.

A total of 52 patients with isolated organic MR was enrolled as a patient group, and 48 age- and gender-matched healthy subjects as a control group. The left atrial emptying fraction (LAEF) and left ventricular ejection fraction (LVEF) were evaluated using apical four-chamber views. The global volume of the LH was calculated as the sum of left atrial (LA) and left ventricular (LV) volumes. The LH emptying fraction (LHEF) was assessed according to the volume-time curve of the LH. All patients underwent echocardiography one day before and within one week after surgery.

The LA, LV and LH volumes were each increased in the patient group (p <0.05). The LVEF of the patient group was comparable to that of controls before surgery (p >0.05), and fell by 10% after surgery (p <0.05). The LAEF of the patient group fell before surgery and also suffered a 10% fall after surgery. Both, baseline and postoperative LHEF were decreased in the patient group (both p <0.05) and remained unchanged after the correction of MR (p >0.05).

By integrating the left atrium and left ventricle as a whole, the LHEF avoided the influence of MR and proved to be a load-independent parameter for global left heart function in patients with MR.