Open AccessEvaluation of Cardiac Phenotype in Horses with Type 1 Polysaccharide Storage Myopathy
Author(s) -
Naylor R.J.,
LuisFuentes V.,
Livesey L.,
Mobley C.B.,
Henke N.,
Brock K.,
FernandezFuente M.,
Piercy R.J.
Publication year - 2012
Publication title -
journal of veterinary internal medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.356
H-Index - 103
eISSN - 1939-1676
pISSN - 0891-6640
DOI - 10.1111/j.1939-1676.2012.00988.x
Subject(s) - medicine , troponin i , myopathy , cardiomyopathy , cardiology , cardiac function curve , incidence (geometry) , endocrinology , gastroenterology , heart failure , myocardial infarction , physics , optics
Background Type 1 polysaccharide storage myopathy ( PSSM 1), an equine glycogen storage disorder caused by a gain of function mutation ( R 309 H ) in the gene encoding glycogen synthase ( GYS 1 ), is associated with the accumulation of amylase‐resistant alpha‐crystalline polysaccharide inclusions within skeletal muscle. Several glycogenoses in humans have a cardiac phenotype, and reports exist of horses with PSSM and polysaccharide inclusions in cardiac muscle. Hypothesis/Objectives To investigate the hypothesis that horses with PSSM1 display a cardiac phenotype. Our objectives were to compare plasma cardiac troponin I ( cTnI ) concentration and the incidence of cardiac arrhythmias in PSSM1 homozygotes, heterozygotes, and control horses. Methods One hundred and twenty‐five B elgian and P ercheron horses under the same management were genotyped for the R 309 H GYS 1 mutation. From these, 8 age‐, breed‐, and sex‐matched cohorts of each genotype were identified. Plasma cTnI concentration and incidence of cardiac arrhythmias (determined by 24‐hour Holter ECG ) were compared between the groups. Results Although some PSSM 1‐affected horses had mildly increased plasma cTnI concentrations, there was no significant difference in cTnI concentrations between groups. There were no significant differences in the incidence of ectopic beats, cardiac conduction intervals or mean heart rate between groups. Conclusions and clinical importance We found no evidence of clinically relevant cardiac myocyte injury or arrhythmias in horses with PSSM 1. Additional study is required to determine whether myocardial function may be compromised in this disorder.