title: Cardiac abnormalities in patients with mitochondrial DNA mutation 3243A>G.
abstract: BACKGROUND
  Tissues that depend on aerobic energy metabolism suffer most in diseases caused by mutations in mitochondrial DNA (mtDNA). Cardiac abnormalities have been described in many cases, but their frequency and clinical spectrum among patients with mtDNA mutations is unknown.
  
  
  METHODS
  Thirty-nine patients with the 3243A>G mtDNA mutation were examined, methods used included clinical evaluation, electrocardiogram, Holter recording and echocardiography. Autopsy reports on 17 deceased subjects were also reviewed. The degree of 3243A>G mutation heteroplasmy was determined using an Apa I restriction fragment analysis. Better hearing level (BEHL0.5-4 kHz) was used as a measure of the clinical severity of disease.
  
  
  RESULTS
  Left ventricular hypertrophy (LVH) was diagnosed in 19 patients (56%) by echocardiography and in six controls (15%) giving an odds ratio of 7.5 (95% confidence interval; 1.74-67). The dimensions of the left ventricle suggested a concentric hypertrophy. Left ventricular systolic or diastolic dysfunction was observed in 11 patients. Holter recording revealed frequent ventricular extrasystoles (>10/h) in five patients. Patients with LVH differed significantly from those without LVH in BEHL0.5-4 kHz, whereas the contribution of age or the degree of the mutant heteroplasmy in skeletal muscle to the risk of LVH was less remarkable.
  
  
  CONCLUSIONS
  Structural and functional abnormalities of the heart were common in patients with 3243A>G. The risk of LVH was related to the clinical severity of the phenotype, and to a lesser degree to age, suggesting that patients presenting with any symptoms from the mutation should also be evaluated for cardiac abnormalities.
authors.affiliation: Department of Internal Medicine, University of Oulu, Oulu, Finland. kirsi.majamaa-voltti@oulu.fi
authors.forename: Kirsi
authors.initials: K
authors.lastname: Majamaa-Voltti
authors.forename: Keijo
authors.initials: K
authors.lastname: Peuhkurinen
authors.forename: Marja-Leena
authors.initials: ML
authors.lastname: Kortelainen
authors.forename: Ilmo E
authors.initials: IE
authors.lastname: Hassinen
authors.forename: Kari
authors.initials: K
authors.lastname: Majamaa
mesh_terms: D001145:Arrhythmias, Cardiac / Q000235:genetics; D001344:Autopsy; D001706:Biopsy; D016022:Case-Control Studies; D004272:DNA, Mitochondrial / Q000235:genetics*; D004452:Echocardiography; D005260:Female; D034381:Hearing Loss / Q000175:diagnosis / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology; D017354:Point Mutation; D018709:Statistics, Nonparametric
chemical_list: D004272:DNA, Mitochondrial