Abstract 16905: Regional Myocardial Work by Magnetic Resonance Imaging and Noninvasive Left Ventricular Pressure: A Feasibility Study in Left Bundle Branch Block
Introduction: We have recently innovated and validated a noninvasive estimate of the left ventricular (LV) pressure curve. This study investigates the feasibility of calculating regional myocardial work from strain by feature tracking magnetic resonance imaging (FTMRI) and noninvasive LV pressure.
Purpose: To determine if regional myocardial work can be measured clinically by MRI and noninvasive LV pressure, and to test the feasibility of this approach in left bundle branch block (LBBB).
Method: In 17 patients with heart failure (9 non-ischemic and 8 ischemic), ejection fraction ≤ 35% and LBBB, circumferential strain was measured by FTMRI in a midventricular short axis cine view. By definition, work during myocardial shortening is positive and work during lengthening is negative. Net work is the sum of positive and negative work. Five non-ischemic patients also underwent 18F-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET). Segmental values were reported as percentages of the segment with maximum myocardium FDG uptake.
Results: Net septal work was -972±1805 (mean±SD), whereas net LV lateral wall work was 2824±1489 mmHgх% (p=0.001). Negative work in the septum implies that energy is absorbed due to work done in the LV lateral wall (Figure 1). A similar pattern was observed in FDG uptake, with septal uptake of 48.1±13.6% and LV lateral wall uptake of 89.3±6.1%. Regional FDG uptake correlated with regional myocardial work (Figure 2).
Conclusions: FTMRI in combination with noninvasive LV pressure demonstrated markedly different workloads on the septum and LV lateral wall in patients with LBBB. Work distribution corresponded well with regional glucose metabolism. These results suggest that FTMRI in combination with noninvasive LV pressure is feasible as a clinical tool to measure regional myocardial work.
Author Disclosures: C.K. Larsen: None. J. Aalen: None. C. Stokke: None. J.G. Fjeld: None. E. Kongsgaard: None. O.A. Smiseth: None. E. Hopp: None.
- © 2016 by American Heart Association, Inc.