Lecture 26 - Hypertension II Flashcards
What is primary hypertension?
Hypertension due to unknown cause - idiopathic essential
What is secondary hypertension?
Hypertension due to a specific cause?
What does salt retention in kidney do to blood volume?
Increases blood volume
How does an increase in blood volume cause an increase in TPR?
Increase in blood volume autoregulation result in arteriolar vasoconstriction arterial compliance decrease - increase in total peripheral resistance (TPR)
What does the sympathetic activation of the arterioles cause?
Arteriolar vasocontraction which decreases arterial compliance
How does a decrease in arterial compliance cause an increase in blood volume?
Arterial compliance decrease - increase TPR less blood flow to kidney - release vasoactive substances and salt retention increase in blood volume
What is the effect of moderate exercise on sympathetic activity?
Balanced increase in sympathetic activity
CO (HR⇧ x SV⇧) x TPR ⇩ = MAP⬄
What is the effect of moderate exercise on sympathetic activity?
Hypertension - systemic increase in overall sympathetic activity
CO (HR⇧ x SV⇧) x TPR ⇧ = MAP⇧
The cause of primary hypertension is thought to be due to:
A. an increase in arterial compliance and/or an increase in arterial blood volume.
B. an increase in arterial compliance and/or a decrease in arterial blood volume.
C. a decrease in arterial compliance and/or an increase in arterial blood volume.
D. a decrease in arterial compliance and/or a decrease in arterial blood volume.
C. a decrease in arterial compliance and/or an increase in arterial blood volume.
What are the consequences of hypertension?
- Kidney disease
- Development of Atherosclerosis – Stroke
- Atrial Fibrillation
- Myocardial Infarction / Coronary artery disease
- Cardiac Remodelling (Hypertrophy - Heart Failure)
Describe Cardiac Remodelling - Afterload
Increases workload (afterload) of the heart
- Stiffer tube (aorta) to eject blood into
- Faster returning reflected pulse wave
Higher resistance to the output
Remodelling – cellular and organ
What increases in cardiomyocyte hypertrophy?
Increase in number of sarcomeres in the cardiomyocytes (size)
NOT in number of cardiomyocytes NOR the size of the sarcomeres!
Why does hypertension cause fibrosis in heart?
Increased load triggers formation of more extracellular matrix (ECM), fibrosis
Increase in collagen type III followed by type I
What makes up the ECM?
Collagen type I + III
Elastin
Proteoglycans
Laminin
Fibronectin
What are the types of pathological caridac remodelling (with fibrosis)?
Hypertension
Hypertrophic cardiomyopathy
Dilated cardiomyopathy/heart failure - Final outcome in all cases
What are the types of physiological caridac remodelling (without fibrosis)?
Endurance athlete - thicker LV walls + LV dilation
Strength athlete - thicker LV wall + mild LV dilation
Combination athlete - Gross thickening of LV walls, LV dilation
What is the cardiac remodelling in hypertension?
Thickening of LV walls, no dilation in early stages of disease
- Pressure overload/concentric
What is the cardiac remodelling in dilated cardiomyopathy/heart failure?
Thinning of LV walls
Significant LV dilation
- Volume overload/eccentric (valve)
What is the cardiac remodelling in hypertrophic cardiomyopathy?
Gross thickening of LV walls
No dilation/decrease in LV chamber
- predominantly genetic mutations
What type of remodelling occurs during hypertension?
Concentric
What type of remodelling occurs with age?
Concentric
What type of remodelling occurs between the sexes?
Male/Female
Eccentric/Concentric
What type of remodelling occurs in coronary artery disease?
Concentric
What type of remodelling occurs in valve leaks?
Eccentric
What type of remodelling occurs in obesity?
Eccentric / concentric
What type of remodelling occurs in diabetes?
Concentric/eccentric
What type of remodelling occurs in familiar dilated cardiomyopathy?
Eccentric
What is the effect of systemic hypertension on the RV?
Early stage - no effect on RV
Late stage - hypertrophied RV
What does the systemic circulating factors do in hypertension?
Increase LV filling pressure which translates into increasing pulmonary circulation
Hypertrophied LV interacts with the RV
In the early stages of hypertension the right ventricle does not remodel BECAUSE the development of atherosclerosis in the aorta increases afterload.
A. Both statements are correct and causally related.
B. Both statements are correct and NOT causally related.
C. Only the first statement is correct and the second statement is incorrect.
D. Only the second statement is correct and the first statement is incorrect.
E. Both statements are incorrect.
B. Both statements are correct and NOT causally related.
What are alternative treatments of hypertension?
Renal denervation
Carotid body denervation
Baroreceptor denervation
