Lecture 50 Flashcards
1
Q
What is LV remodelling?
A
- Normal LV mass
- Increased relative wall thickness
2
Q
What is concentric hypertrophy?
A
- Increased LV mass
- Increased relative wall thickness
- Thick
3
Q
What is eccentric hypertrophy?
A
- Increased LV mass
- Normal relative wall thickness
- Dilated
4
Q
Concentric hypertrophy
A
- Increased wall thickness without LV enlargement
- Increased LV mass
- Often due to pressure overload
- More sarcomeres in parallel to existing sarcomeres
- This is a compensation for pressure overload (high afterload)
- Thicker wall reduces wall stress (Laplace’s law)
- -> The thicker the wall, the less wall stress. This is to maintain systolic function, CO and LVEDP
- Can be a cause of LVH
5
Q
What are some causes of concentric hypertrophy?
A
- HTN
- Aortic stenosis
6
Q
Eccentric hypertrophy
A
- Increase in chamber size and normal relative wall thickness
- increased LV mass
- Often due to volume overload
- Myocyte stretch–> new sarcomeres are added in SERIES to existing ones
- This is a compensation for volume overload (high preload)
- The head is bigger bc it has to pump a bigger SV with each beat
- Bc you want to maintain SV, you have a bigger LVEDV and also increase ejection fraction
- can be cause of LVH
7
Q
What are some causes of eccentric hypertrophy?
A
- Mitral and aortic regurgitation
- Ventricular septal defects
8
Q
Diastolic dysfunction
A
- Thick muscle due to hypertrophy–> shifts muscle
- so you need higher LVEDP to achieve same LVEDV (PRELOAD)
- If you have a stiff ventricle, you need a higher pressure pushing blood INTO ventricle in order for it to fill to a certain volume
- So the PRELOAD PRESSURE is actually a BACK PRESSURE into the LA and pulmonary veins
- This pressure causes fluid to leak out of the pulmonary capillaries, causing pulmonary congestion
- Pts are also more sensitive to fluid loading (HF) or dehydration (decreased BP)
- -> Ventricles being stiff cannot calibrate to new filling pressure
- -> So you have decreased filling of ventricles
- -> This means decreased CO and MAP
9
Q
Other causes of LVH
A
- Following MI or cardiac injury (endocarditis)
- Systemic diseases (obesity, diabetes, renal failure)
- Genetic causes–> hypertrophic cardiomyopathy
10
Q
Clinical identification of LVH
A
- Forceful apex beat (S3 and S4)
- ECG–> will show tall voltages, and inverted T wave
11
Q
Treatment
A
- NO DIRECT TREATMENT
Treat underlying condition- valves etc - HTN–> decrease
- Weight loss
12
Q
LV remodelling
A
- Following MI
- Get increased LV volume and more spherical shape
- Myocyte hypertrophy and apoptosis
- Interstitial fibrosis
13
Q
LV remodelling causes
A
- RAAS defetcs
- Adrenergic NS
- Endothelin
- Cytokines
- Local factors
Leads to increase HF, mortality
14
Q
How can LV remodelling be prevented/ reduced?
A
- Angiotensin blocking
- B adrenergic blocking
15
Q
RVH
A
- Congenital–> e.g. transposition of great arteries
- Pulmonary HTN
- -> Lung disease, pulmonary embolus, chronic L HF
- Right heart valves–> pulmonary stenosis/ regurgitation, tricuspid regurgitation
- NB not as common as L heart valve disease
