333Regional myocardial work by cardiac magnetic resonance and non-invasive left ventricular pressure: a feasibility study in left bundle branch block

Introduction: Incorporating load and wall tension, myocardial work provides a more comprehensive assessment of myocardial function than deformation parameters alone. Regional myocardial work may be calculated by pressure-strain analysis using a non-invasive estimate of left ventricular pressure (LVP). Strain by speckle tracking echocardiography (STE) is not always accessible due to poor image quality. Purpose: To investigate if regional myocardial work can be estimated from strain by feature tracking (FT) cardiac magnetic resonance (CMR) and non-invasive LVP. Methods: 37 heart failure patients with reduced ejection fraction, LBBB, and no myocardial scar were compared to nine controls without LBBB. Circumferential strain was measured by FT-CMR in a midventricular short axis cine view, and longitudinal strain by STE. Segmental work was calculated by pressure-strain analysis. 25 patients underwent 18F-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET). Segmental values were reported as percentages of the segment with maximum myocardial FDG uptake. Results: In the LBBB patients, net CMR-derived work was 51 ± 537 (mean ± SD) in septum, and 1978 ± 1084 mmHg·% (p < 0.001) in the LV lateral wall, while there was a homogeneous work distribution in the controls (Figure). Reproducibility was good. Segmental CMR-derived work correlated with segmental STE-derived work and with segmental FDG uptake (average r = 0.71 and 0.80, respectively). Conclusions: FT-CMR in combination with non-invasive LVP is feasible over a large range, and corresponds well with regional glucose metabolism. FT-CMR is a relevant clinical tool to measure regional myocardial work. Abstract 333 Figure. Calculated pressure-strain loops