Week 5: Cardiovascular 1 - Hypertension, Coronary Artery Disease, Heart Failure Flashcards

1
Q

What is Mean Arterial Pressure?

A

Mean arterial pressure = (stroke volume x heart rate) x systemic vascular resistance
* Stroke volume x heart rate = Cardiac output

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is stroke volume?

A

Stroke volume is the amount of blood pumped from the left ventricle per beat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is heart rate?

A

Heart rate is the speed at which the heart beats (typically measured per minute)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is systemic vascular resistance?

A

Systemic vascular resistance is the resistance applied to the blood by the vessel walls
- Diameter is a key factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How the body response to normal fluctuations

- Baroreceptor reflex

A

Baroreceptor contain in carotid artery - send message to brain stem - brain stem activates either sympathetic or parasympathetic NS to either increase or reduce MAP respectively by stimulating the SA node

The baroreceptor reflex effect and pathway

  • Increase MAP - increase parasympathetic tone which decreases HR which occurs through the neurotransmitter of PNS is acetylcholine that binds to muscarinic acetylcholine receptors at SA node
  • Decrease MAP - increase sympathetic tone which increases HR and SV which occurs through the neurotransmitter of SNS noradrenaline that binds to beta-adrenoreceptors at SA node and cardiomyocyte
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How the body responds to normal fluctuations

- RAAS

A

Renin-angiotensin-aldosterone system (RAAS)

  • Draw pathway
  • Pathway acts to increase SV, increase and increase SVR which increases MAP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Factors contributing to primary hypertension

A
Genetics
Age
Diet (Na+ intake)
Baroreceptor reset
Lifestyle (stressors and increase sympathetic tone)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Goals of anti hypertensives

A
  • Reduce MAP
  • Reduce incidence of micro vascular complications
  • Reduce incidence of macro vascular complications
  • Avoid adverse drug reactions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Factors contributing to the decision to start anti hypertensive therapy

A
  • Not solely based on systolic and diastolic pressure
  • Premised upon patient’s absolute cardiovascular risk
  • Warranted if pressure is persistently > 160/100mmHg
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Anti hypertensive - ACE inhibitors

  • Examples
  • MOA
  • Adverse effects
  • Practice points
A

Examples

  • Ramipril
  • Perindopril
  • Lisinopril
  • Enalapril

MOA
- Inhibit angiotensin converting enzyme which prevents conversion of angiotensin I to angiotensin II

Adverse effects

  • Hypotension
  • Hyperkalaemia
  • Persistent dry cough

Practice points

  • Very effective and often primary selection
  • Involved in Triple Whammy interaction
  • Not to be used in combination with ARB
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Anti hypertensives - Angiotensin receptor blockers (ARB)

  • Example
  • MOA
  • Adverse effects
  • Practice points
A

Examples

  • Candesartan
  • Telmisartan
  • Olmesartan
  • Irbesartan

MOA
- Antagonise the angiotensin type 1 receptor thereby preventing angiotensin II from binding and initiating downstream effects

Adverse effect

  • Hypotension
  • Hyperkalemia

Practice points

  • Often used to replace ACE inhibitor when they are not tolerated
  • Involved in Triple Whammy interaction
  • Not to be used with ACE inhibitors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Anti hypertensives - Calcium channel blockers

  • Why use calcium channel blockers
  • What are the two types of calcium channel blockers
A

Calcium has an effect on the muscle contractility of all muscles including cardiac muscle and arteriole smooth muscle

Two types of calcium channel blockers are

  • Dihydropyridine calcium channel blockers
  • Non-dihydropyridine calcium channel blockers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Anti hypertensives - Dihydropyridine calcium channel blockers

  • Examples
  • MOA
  • Adverse effects
  • Practice points
A

Examples

  • Amlodipine
  • Felodipine
  • Lercanidipine
  • Nifedipine

MOA
- Inhibits influx of calcium into only arteriole smooth muscle (decreases vasoconstriction)

Adverse effects
- Vasodilatory effects (headache, dizziness, hypotension and peripheral edema)

Practice points

  • Selective calcium channel blocker
  • Narrow range of indications (mainly just hypertension)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Anti hypertensive - Non-dihydropyridine calcium channel blocker

  • Example
  • MOA
  • Adverse effects
  • Practice points
A

Examples

  • Diltiazem
  • Verapamil

MOA
- Inhibits influx of calcium into both arteriole smooth muscle (decrease vasoconstriction) and cardiac muscle (decrease chronotropy/inotrophy)

Adverse effects
- Vasodilatory effects (arterial smooth muscle), constipation, bradycardia

Practice points

  • Non selective calcium channel blocker
  • Broad range of indications (beyond hypertension)
  • Serious interaction with beta blockers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Anti hypertensive - Thiazide diuretics

  • Example
  • MOA
  • Adverse effects
  • Practice points
A

Example
- Hydrochlorothiazide

MOA
- Inhibit the reabsorption of Na+ and Cl- within distal convoluted tubule (where sodium goes water follows therefore decrease SV)

Adverse effects

  • At low doses, very well tolerated
  • Electrolyte disturbances

Practice points
- Often taken within a fixed dose combination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Effects of adrenaline and noradrenaline on the body

A

Adrenaline and noradrenaline bind to adrenoreceptors (SNS)

  • Alpha receptors include alpha 1 recepture in vasculature and alpha 2 receptor in brain
  • Beta receptors include beta 1 receptor in heart (increase HR and contractile force), beta 2 receptors in lungs (bronchodilation) and beta 3 receptors in the bladder
17
Q

Anti hypertensives - beta blockers

  • Examples
  • MOA
  • Adverse effects
  • Practice points
A

Examples

  • Atenolol
  • Bisoprolol
  • Metoprolol
  • Carvedilol

MOA
- Selectively antagonise Beta 1 adrenoreceptors in heart therefore preventing (nor)adrenaline from binding and initiating downstream effects (decreases HR and SV)

Adverse effects

  • Bradycardia
  • Bronchospasm
  • Mask hypoglycemia

Practice point

  • Weak anti hypertensive, more useful beyond hypertension
  • Very serious interaction with non-dihydropyridine CaCB
18
Q

Other conditions that use anti hypertensives to manage

A

Stable angina
Post-myocardial infarction
Heart failure (HFrEF)

19
Q

Additional application of anti hypertensives in stable angina

  • Definition
  • Treatment of acute episodes
  • Treatment to prevent acute episodes
A

Stable angina
Definition
- Retrosternal chest discomfort that lasts 10 min or less and subsides with rest
- Occurs when myocardial oxygen demand exceeds supply, which is usually restricted by atherosclerotic obstruction
- Commonly triggered by physical activity or emotional stress

Treatment of acute episodes
- Short acting nitrates such as GTN

Treatment to prevent acute episodes

  • Beta blockers
  • Non dihydropyridine calcium channel blockers
  • Long acting nitrates
20
Q

Nitrates

  • Examples
  • MOA
  • Adverse effects
  • Practice points
A

Examples

  • Glyceryl trinitrate
  • Isosorbide mono nitrate

MOA

  • Produce vasodilation and venodilation which decreases venous return and subsequently decreases preload (reduces SV)
  • Reduces oxygen demand of myocardial tissue

Adverse effects
- Vasodilatory effects (headache, dizziness, hypotension and peripheral edema)

Practice points

  • Can be either short acting (s/l spray) or long acting (patch)
  • Nitrate tolerance develops if there is no nitrate free period per 24 hrs
  • Serious interaction with PDE-5 inhibitors
21
Q

Additional application of anti hypertensives in Post myocardial infarction

A

Beyond scope of this course
Most patients benefit from long term combination therapy of ACE inhibitor to decrease cardiovascular mortality post MI and beta blockers to decrease myocardial O2 requirements

22
Q

Additional application of anti hypertensives in Heart failure (HFrEF)

A

Beyond scope of unit

Most patients benefit from long term combination therapy including ACE inhibitor, beta blocker and loop diuretic

23
Q

Loop Diuretics

  • Example
  • MOA
  • Adverse effects
  • Practice points
A

Example
- Furosemide

MOA
- Inhibit the reabsorption of Na+ and Cl- within ascending limb of loop of Henle (very potent diuretic)

Adverse effects

  • Electrolyte disturbances
  • Dehydration
  • Hypotension

Practice points
- Need to be mindful of diuresis and impact upon adherance