title: Changes in left ventricular function and remodeling after myocardial infarction in hypothyroid rats.
abstract: It has been shown that hypothyroidism may lead to delayed wound healing after experimental myocardial infarction (MI) in rats and increased infarct size in dogs. However, the long-term effect of hypothyroidism on left ventricular (LV) remodeling after MI has not been determined. Adult female Sprague-Dawley rats with and without surgical thyroidectomy (TX) were used in the study. Four weeks after TX, MI or sham MI was performed on TX and non-TX rats. Rats from all groups were examined 4 wk later. Four weeks after TX, hypothyroid-induced LV dysfunction was confirmed by echocardiography. In terminal experiments 4 wk after MI, TX sham-MI rats showed smaller hearts and impaired LV function compared with non-TX sham-MI controls. TX + MI rats showed smaller hearts with bigger infarct areas, higher LV end-diastolic pressures, and greater impairment of relaxation (-dP/dt) compared with non-TX MI rats. Relative changes after MI between TX and non-TX rats for most other hemodynamic and echocardiographic indexes were similar. These results suggest that preexisting hypothyroidism exaggerates post-MI remodeling and worsens LV function, particularly diastolic function.
authors.affiliation: Cardiovascular Health Research Center, Sanford Research/University of South Dakota, Sioux Falls, SD 57105, USA.
authors.forename: Yue-Feng
authors.initials: YF
authors.lastname: Chen
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Redetzke
authors.forename: Suleman
authors.initials: S
authors.lastname: Said
authors.forename: April J
authors.initials: AJ
authors.lastname: Beyer
authors.forename: A Martin
authors.initials: AM
authors.lastname: Gerdes
mesh_terms: D000818:Animals; D001284:Atrophy; D001835:Body Weight / Q000502:physiology; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D007037:Hypothyroidism / Q000150:complications / Q000473:pathology* / Q000503:physiopathology*; D009203:Myocardial Infarction / Q000150:complications / Q000473:pathology* / Q000503:physiopathology*; D009206:Myocardium / Q000473:pathology; D009929:Organ Size / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013963:Thyroid Hormones / Q000097:blood; D013965:Thyroidectomy; D016277:Ventricular Function, Left / Q000502:physiology*; D020257:Ventricular Remodeling / Q000502:physiology*
chemical_list: D013963:Thyroid Hormones