Exercise-induced left ventricular systolic dysfunction in women heterozygous for dystrophinopathy.
BACKGROUND
Mutations in the X-linked gene encoding dystrophin cause skeletal and cardiac muscle diseases in men. Female "carriers" also can develop overt disease. The purpose of this study was to ascertain the prevalence of cardiac contractile abnormalities in dystrophinopathy carriers.


METHODS
Twenty-four dystrophinopathy heterozygotes and 24 normal women each underwent standard exercise stress echocardiography.


RESULTS
Heterozygotes demonstrated mildly lower left ventricular ejection fractions (LVEFs) at rest compared with controls (0.56 + or - 0.10 vs 0.62 + or - 0.07, P = .02). After exercise, the mean LVEF fell to 0.53 + or - 0.14 in heterozygotes but rose to 0.73 + or - 0.07 in controls (P < .001). Twenty-one of 24 dystrophinopathy heterozygotes demonstrated > or = 1 of the following: abnormal resting LVEF, abnormal LVEF response to exercise, or exercise-induced wall motion abnormality.


CONCLUSIONS
Women heterozygous for dystrophinopathy demonstrate significant left ventricular systolic dysfunction, which is unmasked by exercise. This finding has mechanistic implications for both inherited and acquired cardiac disease states.
Weiss
Robert M
RM
University of Iowa Hospitals and Clinics, Division of Cardiovascular Medicine, Department of Internal Medicine, 200 Hawkins Drive, Room E317-1 GH, Iowa City, IA 52242, USA. robert-weiss@uiowa.edu
Kerber
Richard E
RE
Jones
Jane K
JK
Stephan
Carrie M
CM
Trout
Christina J
CJ
Lindower
Paul D
PD
Staffey
Kimberly S
KS
Campbell
Kevin P
KP
Mathews
Katherine D
KD
D000328:Adult; D016189:Dystrophin / Q000235:genetics*; D004452:Echocardiography; D005080:Exercise Test; D005260:Female; D006579:Heterozygote; D006801:Humans; D019656:Loss of Heterozygosity / Q000235:genetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000235:genetics*
D016189:Dystrophin