Strain by speckle tracking echocardiography correlates with electroanatomic scar location and burden in ischaemic cardiomyopathy.

AIMS: Ventricular tachycardia (VT) in ischaemic cardiomyopathy (ICM) originates from scar, identified as low-voltage areas with invasive high-density electroanatomic mapping (EAM). Abnormal myocardial deformation on speckle tracking strain echocardiography can non-invasively identify scar. We examined if regional and global longitudinal strain (GLS) can localize and quantify low-voltage scar identified with high-density EAM.

METHODS AND RESULTS: We recruited 60 patients, 40 ICM patients undergoing VT ablation and 20 patients undergoing ablation for other arrhythmias as controls. All patients underwent an echocardiogram prior to high-density left ventricular (LV) EAM. Endocardial bipolar and unipolar scar location and percentage were correlated with regional and multilayer GLS. Controls had normal GLS and normal bipolar and unipolar voltages. There was a strong correlation between endocardial and mid-myocardial longitudinal strain and endocardial bipolar scar percentage for all 17 LV segments (r = 0.76-0.87, P < 0.001) in ICM patients. Additionally, indices of myocardial contraction heterogeneity, myocardial dispersion (MD), and delta contraction duration (DCD) correlated with bipolar scar percentage. Endocardial and mid-myocardial GLS correlated with total LV bipolar scar percentage (r = 0.83; 0.82, P < 0.001 respectively), whereas epicardial GLS correlated with epicardial bipolar scar percentage (r = 0.78, P < 0.001). Endocardial GLS -9.3% or worse had 93% sensitivity and 82% specificity for predicting endocardial bipolar scar >46% of LV surface area.

CONCLUSIONS: Multilayer strain analysis demonstrated good linear correlations with low-voltage scar by invasive EAM. Validation studies are needed to establish the utility of strain as a non-invasive tool for quantifying scar location and burden, thereby facilitating mapping and ablation of VT.