Abstract 10361: Electrogram Surrogates of the Transmural Extent of Late Gadolinium Enhancement on Cardiac Magnetic Resonance in Patients with Post-Infarct Ventricular Tachycardia
Introduction: Late gadolinium enhancement on cardiac magnetic resonance (LGE-CMR) can accurately characterize scar transmurality and location. However, the correlation of scar transmurality and electrogram (EGM) characteristics has not been investigated in detail. This study aims to define EGM correlates of the transmural extent of post-infarct scar on LGE-CMR.
Methods: LGE-CMR was performed in patients with ischemic cardiomyopathy prior to ventricular tachycardia (VT) ablation. Scar transmurality was calculated in each of 20 radial segments per short axis plane. After the ablation, points from electroanatomic mapping were registered to the short axis LGE-CMR images. The transmural extent (0, 1–25, 26–50, 51–75, 76–90, or 91–100 %) and transmural location (endocardial, mid wall, epicardial, transmural) of scar at each sampled point were correlated with the unipolar and bipolar EGM amplitudes and EGM duration.
Results: A total of 1712 segments in 10 patients were analyzed. Greater scar transmurality was significantly associated with lower unipolar (P<0.001) and bipolar voltage (P<0.001),and prolonged EGM duration (P<0.001) (Figure). Regions with transmural scar had lower EGM amplitudes and longer EGM duration compared with those with non-transmural scar (Bipolar voltage: 0.90±0.61 vs. 0.35±0.18 mV, Unipolar voltage: 4.79±2.05 vs. 2.98±1.83 mV, EGM duration: 138±38.0 vs. 175.4±33.5 ms, respectively; P<0.0001) Critical VT sites were confined to regions with scar on LGE-CMR in all patients. Regions with low voltage were also significantly associated with reduced wall thickness (P<0.001).
Conclusions: The scar transmural extent defined by LGE-CMR was significantly correlated with EGM amplitude and duration in post-infarct scar. LGE-CMR may provide important complementary information to electroanatomical mapping in defining the substrate for post-infarct VT, and may enhance the identification of critical sites for ablation.
- © 2010 by American Heart Association, Inc.