Abstract
Funding Acknowledgements
None declared.
Background and Aims
It is difficult to determine left ventricular systolic performance in patients with severe mitral regurgitation (MR) since left ventricular ejection fraction (EF) could be preserved until the end stages of the disease. Myocardial efficiency describes the amount of external work (EW) done by the left ventricle per unit of oxygen consumed (mVO2). In the present study, we aimed to investigate MEf in patients with asymptomatic severe MR using a novel echocardiographic method. Methods: A total of 27 patients with severe asymptomatic MR and 26 healthy volunteers were included in this cross-sectional study. EW was measured using stroke volume and blood pressure, while mVO2 was estimated using double product and LV mass. Results: There were no differences between the groups with regards to EF (66%±5% vs. 69%±7%), while MEf was significantly reduced in patients with severe MR (25%±11% vs. 44%±12%, p < 0.001) (Table 1). This difference was maintained even after adjustment for age, gender and body surface area (adjusted :0.44, 95%CI: 0.39–0.49 for controls and adjusted :0.24, 95%CI: 0.19–0.29 for patients with severe MR). Further analysis showed that this reduction was due to an increase in total mVO2 in the severe MR group (Figure 1). Conclusions: Myocardial efficiency was significantly lower in patients with asymptomatic severe MR and preserved EF.
Table 1 Parameter Control Group (n = 26) Severe Mitral Regurgitation (n = 27) P Value Age (y) 36.5 ± 8.9 41.3 ± 14.2 0.23 Gender (%Male) 9 (35%) 10 (37%) 1.0 BSA (m2) 1.82 ± 0.20 1.76 ± 0.18 0.64 LV End-Diastolic Volume (ml) 83.13 ± 18.88 121.91 ± 37.63 <0.001 LV End-Systolic Volume (ml) 28.07 ± 9.57 45.30 ± 17.42 <0.001 Left Ventricular Ejection Fraction (%) 0.69 ± 0.07 0.66 ± 0.05 0.29 Systolic Mitral Velocity (cm/s) 7.88 ± 1.14 8.07 ± 1.81 0.66 Stroke Work (j) 1.14 ± 0.21 1.15 ± 0.36 0.91 Minute External Work (j) 65.96 ± 14.71 70.17 ± 23.15 0.85 mVO2 (ml.min-1.100g-1) 6.79 ± 1.93 9.48 ± 4.71 0.02 Total mVO2 (j) 166.58 ± 77.14 346.46 ± 202.71 <0.001 Myocardial Efficiency (%) 44 ± 12 25 ± 11 <0.001 Table 1. Demographic, anthropometric, echocardiographic and mechanoenergetic data for study groups. BSA, body surface area; LV, left ventricle; mVO2, myocardial oxygen consumption.
Abstract 559 Figure 1
THE ESTIMATION OF MYOCARDIAL EFFICIENCY
