Phosphorus-31 two-dimensional chemical shift imaging in the myocardium of patients with late onset of Friedreich ataxia.
OBJECTIVE
Friedreich ataxia (FRDA) is characterized by GAA expansions in the intron 1 of the frataxin gene correlating with disease onset and progression as well as cardiac affection. Accordingly, FRDA patients with early disease onset show a clear impairment of mitochondrial function in the myocardium. The purpose of this study was to investigate cardiac function and high-energy phosphate metabolism in FRDA patients with late disease onset.


METHODS
Using a 1.5 T magnetic resonance scanner, cardiac phosphorus-31 two-dimensional chemical shift imaging was performed in ten patients (seven male, three female) with a late onset of FRDA and in 35 healthy, male controls. Ejection faction (EF) and interventricular septum thickness (IST) were determined by echocardiography.


RESULTS
The differences in left ventricular phosphocreatine (PCr) to beta-adenosine triphosphate (beta-ATP) ratios between both groups were not significant. FRDA patients had increased ISTs (10.8+/-1.6 vs. 9.7+/-0.9 mm; p=0.048), which correlated significantly with the left ventricular PCr to beta-ATP ratios (r= -0.644; p=0.04), and decreased EFs (52.24+/-7.72% vs. 64.09+/-4.25%; p=0.001) compared to normal controls.


CONCLUSIONS
In contrast to FRDA patients with early disease onset, our patients collective exhibited a normal, probably compensated cardiac mitochondrial function, whereby IST and EF were mildly altered.
Wolf
Christian
C
Department of Radiology I, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria.
Boesch
Sylvia
S
Metzler
Bernhard
B
Weirich-Schwaiger
Helga
H
Trieb
Thomas
T
Schocke
Michael F H
MF
D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D017668:Age of Onset; D003710:Demography; D005260:Female; D005621:Friedreich Ataxia / Q000453:epidemiology / Q000378:metabolism*; D006352:Heart Ventricles / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009206:Myocardium / Q000473:pathology*; D010725:Phosphocreatine / Q000378:metabolism; D010759:Phosphorus Isotopes
D010759:Phosphorus Isotopes; D010725:Phosphocreatine; D000255:Adenosine Triphosphate