Changes in left ventricular function and remodeling after myocardial infarction in hypothyroid rats.
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.
Chen
Yue-Feng
YF
Cardiovascular Health Research Center, Sanford Research/University of South Dakota, Sioux Falls, SD 57105, USA.
Redetzke
Rebecca A
RA
Said
Suleman
S
Beyer
April J
AJ
Gerdes
A Martin
AM
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*
D013963:Thyroid Hormones