Abstract 10920: Mechanical Dispersion by Strain Echocardiography is a Marker of Ventricular Arrhythmias in Lamin A/C Mutation Positive Subjects
Background: Mutations in the Lamin A/C gene cause a malignant type of familial dilated cardiomyopathy (DCM) with increased risk of ventricular arrhythmia (VA) and sudden cardiac death even before development of DCM. Echocardiographic mechanical dispersion, reflecting contraction heterogeneity, has been shown to accurately predict VA in different cardiomyopathies. We explored if mechanical dispersion could predict VA in Lamin A/C mutation positive subjects.
Methods: We included 33 Lamin A/C mutation positive probands (39%) and family members (61%) (age 35±16 years, follow-up time 42  months). VA was documented and defined as non-sustained ventricular tachycardia (VT), sustained VT or ventricular fibrillation (VF). By echocardiography, left ventricular (LV) function was assessed as ejection fraction (EF) and as global longitudinal strain (GLS) from 2D speckle tracking. GLS was calculated as average peak strain from 16 LV segments. Mechanical dispersion was defined as the standard deviation of time to peak strain from the 16 LV segments.
Results: Eleven (33%) subjects had documented VA (6 (18%) had non-sustained VT and 5 (15%) had sustained VT/VF). Mechanical dispersion was significantly increased in those with VA compared to those without (49±14 ms vs. 38±10 ms, p = 0.02). GLS and EF were not markers of VA ([[Unable to Display Character: ‐]]19.2±5.3% vs. [[Unable to Display Character: ‐]]21.0±2.9%, p=0.22 and 47±15% vs 53±7%, p=0.14). There was a significant linear trend towards an increase of mechanical dispersion along with severity of VA (38ms, 42ms and 57 ms in subjects without VA, with non-sustained VT and sustained VT/VF respectively, p=0.001) (Figure).
Conclusion: Mechanical dispersion was a marker of VA in Lamin A/C mutation positive subjects. Heterogeneous contraction may reflect underlying myocardial arrhythmogenic changes. Assessment of mechanical dispersion may help prediction of VA in Lamin A/C mutation positive subjects independently of EF and GLS.
- © 2013 by American Heart Association, Inc.