Abstract 13312: Can the Extent of Late Gadolinium Enhancement on Cardiac Magnetic Resonance Be Predicted by the 12-Lead Electrocardiogram?

Abstract

Background: In hypertrophic cardiomyopathy (HCM), late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) is an in vivo marker of replacement fibrosis with a continuous relationship between amount of LGE and both risk for sudden death and development of endstage disease. Cost and accessibility can limit routine utilization of CMR. In contrast, electrocardiogram (ECG) is an inexpensive readily available test and identifies patients with myocardial scarring in ischemic heart disease. Its ability to identify presence and extent of LGE in HCM is unknown. Methods: 1983 consecutive HCM patients were included; 62% male, average wall thickness 18 ± 3mm, and 36% with resting LV outflow tract obstruction ≥ 30mmHg. ECGs were analyzed for LV hypertrophy, T wave abnormalities, ST-segment depression or elevations, abnormal Q waves, conduction disease, atrial enlargement and QTc prolongation. Extent of LGE was quantified and expressed as a proportion of total LV myocardium. Results: 822 (41%) had no LGE, while 1161 (59%) had LGE, including 687 (35%) with <5%, 299 (15%) with 5-9%, 92 (5%) with 10-14%, and 83 (4%) with ≥ 15%. Compared to no LGE, Patients with LGE were more likely to have pathologic T wave inversions (55% vs. 36%, p<0.01), positive T waves in aVR (34% vs. 20%, p<0.01), and ST-depressions (29% vs. 21%, p<0.01), with no difference in LV hypertrophy, bundle branch block, pathologic Q waves, first degree AV block, QTc prolongation ≥ 480ms, or ST-elevations (p>0.05). Notably, as extent of LGE increased there was a corresponding progressive increase in the prevalence of both positive T waves in aVR (20% in no LGE to 42% in ≥ 15% LGE, p<0.01) and pathologic T wave inversions (36% in no LGE to 61% in ≥ 15% LGE, p<0.01) but with no incremental differences in ST depressions (p>0.05). In contrast, 43% of patients with LGE did not have either positive T waves in aVR or pathologic T wave inversions, including 34% with ≥ 15% LGE. Conclusion: Most ECG findings including pathologic Q waves have no relation to presence or extent of LGE. While positive T waves in aVR and pathologic T wave inversions are associated with LGE, they have limited sensitivity. These finding support that routinely evaluated ECG abnormalities do not predict presence or extent of scarring in HCM.