Abstract 18242: Left Ventricular Non-Compaction on Cardiac Magnetic Resonance Imaging is prevalent in patients with Myotonic Dystrophy

Abstract

Aims: Myotonic dystrophy (MD) is an autosomal dominant neuromuscular disorder characterised by myotonia, skeletal muscle weakness and multi-system disease. Patients with MD are at high risk of premature cardiovascular death related primarily to arrhythmias, conduction abnormalities and dilated cardiomyopathy. Cardiac magnetic resonance imaging (cMR) is the optimal modality to detect early abnormalities of left ventricular (LV) structure and function. There are, however, few data exploring the prevalence of cMR abnormalities in this setting. The aim of the current study is therefore, to address this.

Methods: Forty patients with MD and 41 age and gender matched controls underwent clinical evaluation, standard 12 lead EKGs, 24 hour Holter monitoring, echocardiography and cMR. Cardiac MR scans were analysed by blinded two observers.

Results: There was a significantly higher prevalence of compaction abnormalities in patients with MD (non-compaction [NC] in 34% in MD vs. 12% in controls; p=0.02). LV function, however, was similar in MD patients and controls, (MD mean EF = 58 standard deviation [SD] 7% vs. mean 59 SD 6% in controls, p = 0.4). PR interval and QRS durations were also significantly prolonged in patients with MD (mean MD PR interval = 186 SD 29 ms vs. 155 SD 24 ms, mean MD QRS duration = 100 ms SD 12ms vs. 88 ms SD 9 ms in controls; p <0.001 for both). There was no significant difference in QTc in MD patients compared to controls (MD mean QTc = 410 SD 10 ms. vs. 409 SD 15 ms. in controls p=0.51). Among patients with myotonic dystrophy, there were no significant differences in the PR, QRS durations and the QTc between patients with normal compaction and NC (p=0.87). No other Holter parameters correlated with NC.

Conclusion: LV non-compaction is common in patients with MD and has not been well characterised previously. Non-compaction in patients with MD is not associated with conduction abnormalities within this cohort. The clinical relevance of these findings require further study.