Hypercholesterolemia and Myocardial function evaluated via Tissue Doppler Imaging

Abstract

ObjectiveTo establish a link between hypercholesterolemia and myocardial dysfunction.BackgroundHeart failure is a complex disease involving changes in systolic and diastolic function. Newer echocardiographic imaging modalities may be able to detect discreet changes in myocardial function associated with hypercholesterolemia. Therefore we sought to establish a link between hypercholesterolemia and myocardial dysfunction with tissue Doppler imaging (TDI).MethodsTwenty-seven rabbits were studied: 7 were fed normal chow (group 1) and 20 a high cholesterol diet (10 with ezetimibe, 1 mg/kg/day; group 2 and 10 without, group 3). Echocardiographic images were obtained under general anesthesia. Serum cholesterol levels were obtained at baseline, 3 and 6 months and myocardial cholesterol levels measured following euthanasia.ResultsDoppler measurements, including E/A, E'/A' and S' were significantly lower in group 3 compared to both groups 1 and 2 but no significant differences were noted in chamber sizes or ejection fraction among the groups. Average serum cholesterol was higher in group 3 compared to groups 1 and 2 respectively (495 ± 305 mg/dl vs. 114 ± 95 mg/dl and 87 ± 37 mg/dl; p < 0.01). Myocardial cholesterol content was also higher in group 3 compared to group 2 (0.10 ± 0.04 vs. 0.06 mg/dl ± 0.02; p = 0.05). There was significant correlation between S', E'/A', E/E' and serum cholesterol (r2 = 0.17 p = 0.04, r2 = 0.37 p = 0.001 and r2 = 0.24 p = 0.01).ConclusionCholesterol load in the serum and myocardium was significantly associated with decreased systolic and diastolic function by TDI. Moreover, lipid lowering was protective.

Short-Term Exposure to Exogenous Lipids in Premature Infants and Long-Term Changes in Aortic and Cardiac Function

“…Furthermore, because animal models have also shown a direct relationship between diet-induced hyperlipidemia and myocardial dysfunction, 13,14 we determined whether lipid exposure has effects beyond the vasculature and used cardiovascular magnetic resonance to study long-term variation in left ventricular structure and function.…”

“…Acute direct effects of a high-lipid diet on myocardial function have been reported in several animal models. 13,14,49 Whether such insults have long-term effects and are particularly influential during early stages of cardiac development has not been studied. We were able to include myocardial tagging as a sensitive marker of early changes in myocardial function in a proportion of our young adults.…”

Role of lipids and lipoproteins in myocardial biology and in the development of heart failure

“…However, these rabbit studies should be interpreted with caution. Indeed, plasma cholesterol levels in these studies were approximately 500 mg/dl [73] and 800 mg/dl [74], which is rarely observed in humans.…”

“…Hypercholesterolemia in rabbits induces electrical remodelling of the heart, characterized by prolongation of the action potential and of the heart rate corrected QT interval, increased repolarization dispersion, and 390 vulnerability to ventricular fibrillation [72]. Using tissue Doppler imaging, systolic and diastolic dysfunction has been demonstrated in hypercholesterolemic rabbits [73].…”

Protective role of coenzyme Q 10 against high cholesterol dietinduced histological and biochemical changes in cerebellar cortex of adult albino rats

“…Cholesterol is an essential component of cell membrane and it is essential in many biochemical processes and support building cell membranes [3], but hypercholesterolemia is proved to be associated with negative health outcomes as cardiovascular diseases [4].…”