Structural and functional cardiac changes in myotonic dystrophy type 1: a cardiovascular magnetic resonance study

Abstract

BackgroundMyotonic dystrophy type 1 (MD1) is a neuromuscular disorder with potential involvement of the heart and increased risk of sudden death. Considering the importance of cardiomyopathy as a predictor of prognosis, we aimed to systematically evaluate and describe structural and functional cardiac alterations in patients with MD1.MethodsEighty MD1 patients underwent physical examination, electrocardiography (ECG), echocardiography and cardiovascular magnetic resonance (CMR). Blood samples were taken for determination of NT-proBNP plasma levels and CTG repeat length.ResultsFunctional and structural abnormalities were detected in 35 patients (44%). Left ventricular systolic dysfunction was found in 20 cases, left ventricular dilatation in 7 patients, and left ventricular hypertrophy in 6 patients. Myocardial fibrosis was seen in 10 patients (12.5%). In general, patients had low left ventricular mass indexes. Right ventricular involvement was uncommon and only seen together with left ventricular abnormalities. Functional or structural cardiac involvement was associated with age (p = 0.04), male gender (p < 0.001) and abnormal ECG (p < 0.001). Disease duration, CTG repeat length, severity of neuromuscular symptoms and NT-proBNP level did not predict the presence of myocardial abnormalities.ConclusionsCMR can be useful to detect early structural and functional myocardial abnormalities in patients with MD1. Myocardial involvement is strongly associated with conduction abnormalities, but a normal ECG does not exclude myocardial alterations. These findings lend support to the hypothesis that MD1 patients have a complex cardiac phenotype, including both myocardial and conduction system alteration.

Lactate levels affect motor performance in MD 1

“…The interest of our study consists of the fact that our protocol is a safe, non exhaustive and easy reproducible method to be performed in such patients, who may frequently present early structural and functional myocardial abnormalities, strongly associated with cardiac conduction alterations. 31,32 Our findings confirm the alteration in oxidative capacity of DM1 skeletal muscle, which could negatively influence motor performances of these patients. The relevance to know one of the mechanisms implied in fatigue in DM1 consists of the possibility to state aerobic capacity of these patients, in order to plane specific rehabilitative protocols.…”

Cardiac Involvement in Myotonic Dystrophy Type 2 Patients With Preserved Ejection Fraction

“…33 A recent study investigated 80 patients with DM1. 34 There, in 13% of all patients, myocardial fibrosis was detected applying LGE imaging, although one fourth of the study cohort presented LV systolic dysfunction. In DM2, only 1 case report exists postulating focal myocardial fibrosis in a 68-year-old woman.…”

Myotonic dystrophy and the heart: A systematic review of evaluation and management

“…Ventricular tachycardia arising from the left anterior or posterior fascicles has also been reported [36] as has QT interval prolongation and torsade de pointes [37]. Sudden cardiac death may result from ventricular tachycardia or ventricular fibrillation [9].…”

“…Cardiac magnetic resonance (CMR) imaging is an accurate and highly reproducible technique for assessment of cardiac volumes, function, mass and fibrosis, with inter-study reproducibility superior to 2D echocardiography [9]. It is also a superior modality for studying the right ventricle [72].…”