The Heart in Friedreich Ataxia: Definition of Cardiomyopathy, Disease Severity, and Correlation with Neurological Symptoms
Background—This cross sectional study provides a practical approach for the clinical assessment of Friedreich ataxia (FA) cardiomyopathy (FA-CM).
Methods and Results—A comprehensive cardiac assessment, including standard echocardiography, color Doppler myocardial imaging (CDMI), cardiac magnetic resonance imaging (cMRI), electrocardiography (ECG) and exercise stress testing was performed in 205 FA patients. To assess myocardial hypertrophy in FA-CM, the end-diastolic interventricular septal wall thickness (IVSTd) was found to be the best echocardiographic parameter when compared to cMRI-determined left ventricular mass. Using this parameter, four groups of FA-CM could be defined. Patients with normal values for IVSTd (31.7%) classified as "no FA-CM". Patients with an IVSTd exceeding the predicted normal IVSTd were classified as "mild FA-CM" (40%) if IVSTd exceeds the normal value by < 18% or as "intermediate FA-CM" (16.1%) if IVSTd exceeds by ≥18%. Patients with ejection fraction (EF) <50% were classified as "severe FA-CM" (12.2%). Besides increased myocardial mass, severe FA-CM was further characterized by dilatation of the left ventricle, reduced systolic strain-rate of the posterior wall, and ECG abnormalities. Regional myocardial function correlated negatively with FA-CM groups. Younger patients had a tendency for a more advanced FA-CM. Importantly, no clear correlation was found between FA-CM groups and neurological function.
Conclusions—We provide and describe a readily applicable clinical grouping of the cardiomyopathy associated with FA based on echocardiographic IVSTd and EF data. As no distinct interrelations between FA-CM and neurological status could be determined, regular follow-up of potential cardiac involvement in FA patients is essential in clinical practice.
Clinical Trial Registration Information—Clinicaltrials.gov; ID: NCT00905268.
- Received August 9, 2011.
- Accepted January 24, 2012.
- Copyright © 2012, American Heart Association, Inc. All rights reserved. Unauthorized use prohibited