Myocardial fibrosis by late gadolinium enhancement cardiovascular magnetic resonance in myotonic muscular dystrophy type 1: highly prevalent but not associated with surface conduction abnormality

J Cardiovasc Magn Reson. 2019 May 2;21(1):26. doi: 10.1186/s12968-019-0535-6.

Abstract

Background: Conduction disease and arrhythmias represent a major cause of mortality in myotonic muscular dystrophy type 1 (MMD1). Permanent pacemaker (PPM) implantation is the cornerstone of therapy to reduce cardiovascular mortality in MMD1. Cardiovascular magnetic resonance (CMR) studies demonstrate a high prevalence of myocardial fibrosis in MMD1, however the association between CMR myocardial fibrosis with late gadolinium enhancement (CMR-LGE) and surface conduction abnormality is not well established in MMD1. We investigated whether myocardial fibrosis by CMR-LGE is associated with surface conduction abnormalities meeting criteria for PPM implantation according to current guidelines in a cohort of patients with genetically confirmed MMD1.

Methods: Patients with genetically confirmed MMD1 were retrospectively evaluated. 12-lead electrocardiography (ECG) performed within 6 months of CMR was necessary for inclusion. The severity and extent of MMD1 was quantified using a validated Muscular Impairment Rating Scale (MIRS). Based on current guidelines for device-based therapy of cardiac rhythm abnormalities, we defined surface conduction abnormality as the presence of ECG alterations meeting criteria for PPM implant (class I or II indications): PR interval > 200 ms (type I atrioventricular (AV) block) and/or mono or bifascicular block (QRS > 120 ms), or evidence of advanced AV block. Balanced steady-state free precession sequences (bSSFP) were used for assessment of left ventricular (LV) volumes and ejection fraction. MOdified Look-Locker Inversion Recovery (MOLLI) acquisition schemes were used to acquire T1 maps. Patients' charts were reviewed up to 12 months post-CMR for occurrence of PPM implantation.

Results: Fifty-two patients (38% male, 41 ± 14 years) were included. Overall, 31 (60%) patients had a surface conduction abnormality and 22 (42%) demonstrated midwall myocardial fibrosis by CMR-LGE. After a median of 57 days from CMR exam, 15 patients (29%) underwent PPM implantation. Subjects with vs. without surface conduction abnormality had significantly longer disease length (15.5 vs. 7.8 years, p = 0.015) and higher disease severity on the MIRS scale (p = 0.041). High prevalence of myocardial fibrosis by CMR-LGE was detected in subjects with and without surface conduction abnormality with no significant difference between the two cohorts (42% vs. 43%, p = 0.999). By multivariate logistic regression analysis, disease length was the only independent variable associated with surface conduction abnormality (OR 1.071, 95%CI 1.003-1.144, p = 0.040); while CMR-LGE was not associated with conduction abnormality (ρ = - 0.009, p = 0.949).

Conclusions: Myocardial fibrosis by CMR-LGE is highly prevalent in MMD1 but not related to surface conduction abnormality meeting current guideline criteria for PPM implantation .

Keywords: Cardiovascular magnetic resonance; Electrocardiogram; Late gadolinium enhancement; Myocardial fibrosis; Myotonic muscular dystrophy; Pacemaker.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Arrhythmias, Cardiac / diagnosis
  • Arrhythmias, Cardiac / epidemiology*
  • Arrhythmias, Cardiac / therapy
  • Cardiac Pacing, Artificial
  • Cardiomyopathies / diagnostic imaging*
  • Cardiomyopathies / epidemiology
  • Cardiomyopathies / pathology
  • Contrast Media / administration & dosage*
  • Female
  • Fibrosis
  • Humans
  • Magnetic Resonance Imaging, Cine*
  • Male
  • Middle Aged
  • Myocardium / pathology*
  • Myotonic Dystrophy / diagnosis
  • Myotonic Dystrophy / epidemiology*
  • Myotonic Dystrophy / genetics
  • Ohio / epidemiology
  • Predictive Value of Tests
  • Prevalence
  • Retrospective Studies
  • Risk Factors

Substances

  • Contrast Media