Dilatation cardiomyopathy Flashcards
What is myocardial remodelling?
Myocardial remodelling is caused by pathologic hypertrophy of the ventricles. It is basically changes to the heart structure and function associated with heart failure.
Explain altered calcium handling with respect to myocardial remodeling?
Altered calcium handling is when we see a shift to extracellular calcium cycling instead of using the calcium in the SR like normal.
What exactly causes altered calcium handling?
It is the reduction in the number of SERCA pumps (SR Calcium ATPases). These channels pump calcium back into the SR from the myocyte cytoplasm after a contraction. Decreased SERCA expression causes decreased calcium in the SR, resulting in altered calcium cycling.
What is cardiac fibrosis, and what other heart failure condition tend to occur with it?
Cardiac fibrosis is the thickening of cardiac valves due to inappropriate fibroblast proliferation in cardiac tissue. The thickening of the cardiac valves causes them to function abnormally, causing other cardiac valve diseases like mitral regurgitation, atrial arrythmia and dyssynchony.
What is mitral regurgitation?
This is when the mitral valve between the left ventricle and atrium doesn’t work properly anymore. So, as the left atrium contracts to push blood into the left ventricle, the blood flows right back into the left atrium again because the mitral valve doesn’t shut properly.
What is the effect of mitral regurgitation on the left atrium?
The left atrium increases in size due to stretch, and the wall thickens to push blood out at a higher pressure. This causes left atrial pathological changes. It causes atrial-ventricular dyssynchrony.
What is atrial arrhythmia and atrial fibrillation?
Atrial arrythmia is the uncoordinated, irregular contraction of the atrium. This preceeds atrial fibrillation, which is the complete loss of atrial synchronised heart beats. The atrial beats are uncontrolled and random.
Is SERCA pump expression altered in Atrial fibrillation?
Yep. SERCA pump expression is decreased in atrial fibrillation.
What is SERCA pump gene therapy?
Since SERCA pump expression is decreased in heart failure, then by injecting genes into the heart for SERCA pump expression into the cardiac myocytes, it should increase expression of these pumps.
Does SERCA pump gene therapy work?
Yep. By increasing SERCA pump expression in the myocytes then there is an increased ejection fraction of the heart. There is also increased pressure of the blood being pumped out by the heart.
