Abstract 215: Two-Dimensional Speckle Tracking Echocardiography to Assess Changes in Left Ventricular Torsional Dynamics During Exercise is a Better Predictor of Exercise Capacity and Myocardial Dysfunction Compared with E/E′ Estimation
Introduction: Left ventricular (LV) diastolic filling pressure (E/E′) assessed with 2D echocardiography during exercise has been validated with catherisation findings and can predict exercise capacity. 2D speckle tracking echocardiography allows for assessment of myocardial LV torsional deformation as a composite function of the radial, longitudinal and circumferential fibers.
Hypothesis: LV torsional dynamics pre- and post-exercise is a better predictor of exercise capacity and myocardial dysfunction compared to post-exercise E/E′.
Methods: We evaluated 40 patients referred for stress echo to assess shortness of breath. Treadmill exercise was performed using Bruce protocol, and echo images acquired using GE Vivid 7 set at high frame-rate. GE ECHOPAC software was used for analysis. Speckles in 2D images as tissue markers were used to track LV contraction. Greater than 20 markers were selected at the LV base and apex and tracked. Patients with reversible ischemia were excluded. LV torsion was calculated as difference between clockwise rotation of the base and counter-clockwise rotation of the apex. Patients were divided into three groups according to the percentage predicted exercise capacity (achieved metabolic equivalents, METS), adjusted for age and gender. Comparison was made between LV torsion and E/E′, and their correlation to achieved METS determined.
Results: Mean age 57, female = 18, male = 22, all with normal resting LV ejection fraction. No significant correlation between METS and LV torsion at rest. Correlation between post-exercise E/E′ with METS (r=0.48, p<0.05). Greater correlation between LV torsion post-exercise (r=0.68, p<0.01). Torsion incremental Δ correlate well with METS (r=0.46, p<0.05).
Conclusion: LV torsional dynamics post-exercise and torsion incremental change is a good predictor for exercise capacity, and is a useful tool in assessment for myocardial dysfunction beyond E/E′ in patients with reduced exercise tolerance.