Lecture 4 Flashcards
Cardiomyopathies
What is eccentric (outward) remodelling?
The heart has a thin wall and lower systolic force. Happens during systolic heart failure
What is concentric (inward) remodelling?
The heart gets a thicker wall. Happens during diastolic heart failure
When is something called idiopathic myopathy?
When the cause is not found
What other myopathies are there (apart from idiopathic)?
Ischemic, familial and diabetic (complex)
What causes dilated cardiomyopathy?
Either ischemia or a gene defect
Which heart functions are altered during dilated cardiomyopathy?
It has a lower contractility, a smaller stoke volume and a smaller ejection fraction
What part of the heart is mainly affected by hypertrophic cardiomyopathy?
The septum
Can anything be done in hypertrophic cardiomyopathy to remove it?
A part of the septum could be removed if it blocks too much of the aorta
What causes hypertrophic cardiomyopathy?
Due to either obesity, diabetes or gene defects
Which heart functions are altered during dilated cardiomyopathy?
Have a high ventricular pressure and insufficient filling
Which (type of) genetic defects can be detected in hypertrophy?
There is a heterozygous mutation in the sarcomere eg MYH7, MYBPC3 and TNNT2
Some general info about the hypertrophy mutation?
If there are two mutations a heart transplant is needed. Everyone with a mutation develops some syptoms
What is an early symptom of a hypertrophy mutation?
Impaired relaxation
Why is there disease progression of hypertrophy mutation when you get older?
The mutant protein levels become higher, which leads to the progression of the disease
How do you measure tension development and ATP consumption in the heart muscle?
By isolating muscle strips. The ratio of ATP/force gives the tension cost of the sarcomere.
What is a control group in research conducted on hypertrophy mutations?
Patients that do have the disease but do not have any of the mutations
What can be said about the tension and ATP in patients with a hypertrophy mutation?
They have higher tension and higher ATP
How do you calculate the ATP for a carrier of the hypertrophy mutation?
By dividing the work by the O2 consumption. Has a higher O2 consumption with the same work, thus a lower cardiac efficiency
What is the energy consumption of 100% actin bound myosin?
Very high energy consumption
What is SRX?
It is a supper relaxed myosin that is only recruited when it is needed
What is the energy consumption of SRX?
It has a low energy consumption
What does DRX stand for?
Disregulated myosin
What is the energy consumption of DRX?
The energy consumption is high
What are the normal percentages of bound, SRX and DRX myosin?
10% bound, 45% SRX, 45% DRX
