Abstract 16516: CMR-ECG Imaging in Hypertrophic Cardiomyopathy Detects Electrophysiological Abnormalities Before Hypertrophy or ECG Changes
George Joy, Matthew Webber, Alessandra M Ardissino, James Wilson, Fiona Chan, Rebecca Hughes, Konstantinos Moschonas, Hunain Shiwani, Iain Pierce, Robert Jamieson, Vladan Koncar, xuyuan tao, Christoph Guger, Paula Velazquez, Erica Dall'Armellina, Peter Macfarlane, Peter Kellman, Rhodri Davies, Maite Tome, Yoram Rudy, Alun Hughes, Charlotte Manisty, Pier Lambiase, James C Moon, Luis Lopes, Michele Orini, Gabriella Captur- Physiology (medical)
- Cardiology and Cardiovascular Medicine
INTRODUCTION: In hypertrophic cardiomyopathy (HCM), ventricular arrhythmia associates with severity of LVH and scar, and presence vs absence of a sarcomeric gene mutation (G+LVH+ vs G-LVH+). Also, ECG changes in subclinical HCM (G+LVH-) signal increased risk of phenotype progression.
HYPOTHESES: ECG Imaging (ECGI) can detect: i) subtle electrophysiological (EP) abnormalities in subclinical HCM (pre-LVH). ii) EP abnormalities related to genetic status (G+ vs G-LVH+) and structural changes (late gadolinium enhancement [LGE], max. wall thickness [MWT]) in overt disease.
METHODS: 200 participant multicenter study: 70 G+LVH-, 51 G+LVH+, 53 G-LVH+ and 26 healthy volunteers (HV) underwent 12-lead ECG (to detect abnormal Q-waves, repolarization changes, LVH criteria) and CMR-ECGI computing epicardial unipolar electrograms (UEGs) to derive: activation time (AT), activation-recovery intervals (ARIc), spatial gradients (activation: G AT , repolarisation: G RT ) and fractionation.
RESULTS: Compared to HV, G+LVH- had prolongation of AT (40.3±7.3 vs 35.4±6.1 ms p=0.003) and steeper G RT (mean: 1.12±0.27 vs 1.00±0.23 ms/mm p=0.042, max: 11.7±2.8 vs 10.0±1.9 ms/mm p=0.005). AT was prolonged even in G+LVH- with a normal 12-lead ECG (p<0.004).
Compared to G+LVH-, G+LVH+ had similar AT but a more prolonged ARIc (275±29 vs 245±26 ms p<0.001).
Compared to G-LVH+, G+LVH+ had similar MWT and LGE, but more signal fractionation (0.02±0.02 vs 0.01±0.03% UEGs with ≥2 deflections p=0.002).
In overt HCM (all LVH+), MWT associated with AT ( r s 0.25 p=0.011) while LGE burden associated with G AT ( r s=0.27 p=0.006) and fractionation ( r s=0.22 p=0.025).
CONCLUSION: Cardiac activation prolongation and repolarization abnormalities occur in subclinical HCM (before hypertrophy). Activation is prolonged even in subclinical HCM with normal 12-lead ECG. In overt HCM, ECGI abnormalities track adverse structural changes and reveal greater fractionation in those with a sarcomeric mutation.