Association of regional myocardial conduction velocity with the distribution of hypoattenuation on contrast-enhanced perfusion computed tomography in patients with postinfarct ventricular tachycardia.

BACKGROUND: Cardiac magnetic resonance imaging has been shown to be beneficial for identification of the ventricular tachycardia (VT) substrate before catheter ablation. Contrast-enhanced perfusion multidetector computed tomography (CEP-MDCT) is more generalizable to clinical practice, and wall thickness and regional hypoenhancement on CEP-MDCT can identify potential substrate sites, albeit with decreased specificity.
OBJECTIVE: The purpose of this study was to evaluate the association between wall thickness and attenuation on CEP-MDCT with local conduction velocity (CV) and electrogram abnormalities in patients with postinfarct VT.
METHODS: Fourteen patients with postinfarct VT underwent preprocedural CEP-MDCT followed by endocardial electroanatomic mapping (EAM) and ablation. Myocardial attenuation and wall thickness were calculated from 3-dimensional MDCT images using ADAS-VT software (Galgo Medical). EAM was registered with 3-dimensional MDCT images using the CartoMERGE module of CARTO3 software (Biosense Webster). Local CV was calculated by averaging the velocity between each point and 5 adjacent points with concordant wavefront direction.
RESULTS: A total of 3689 points were included. In multivariable regression analysis clustered by patient, local CV was positively associated with myocardial attenuation, bipolar voltage, unipolar voltage, and wall thickness. Each 10-HU drop in full-thickness attenuation correlated to 2.6% decrease in CV (P <.001) and 5.5% decrease in bipolar voltage amplitude (P <.001), after adjusting for wall thickness.
CONCLUSION: Myocardial attenuation distribution on CEP-MDCT is associated with regional CV and electrogram amplitude. Regions with low CV identified with low attenuation on CEP-MDCT may serve as important VT substrates in postinfarct patients.