CXA240 Pathophysiology for Health Care

Alterations in Cardiovascular Health

Intended Learning Outcomes:

Actively participating in these activities will increase your ability to:

• apply clinical reasoning
• assess cardiovascular disease risk and plan evidence-based care for primary prevention of cardiovascular health conditions
• evaluate the possible causes of chest pain
• discuss pathophysiological mechanisms in relation to coronary artery disease
• explain the rationale for ECG and blood tests in the assessment of ACS
• explain the rationale for common medicines in the medical management of ACS
• discuss pathophysiological mechanisms related to chronic heart failure
• plan for the safe administration of medications

 

Resources that you may find useful to achieve the learning outcomes:

• Bullock, S, Hales, M (2019), Principles of Pathophysiology, 2^nd  Pearson: Australia
• Bullock, S, Manias, E. (2016), ‘Fundamentals of Pharmacology, 8thEd. Pearson: Australia
• Amerman, E. C. (2019). Human anatomy & physiology., 2^nd Global Ed. Pearson: Australia
• Norris, T.L. (2019). Porth’s Essentials of Pathophysiology: Concepts of Altered Health States, 5^th Wolters Kluwer: USA
• Australian Medicines Handbook Online. https://amhonline.amh.net.au/
• Heart Foundation https://www.heartfoundation.org.au/

 

 

 

Activity 1: Control of Blood Pressure

Aim: to demonstrate understanding of factors affecting cardiovascular physiology by explaining how their alteration affects the Mean Arterial Blood Pressure. 

 

This figure illustrates the set of formulae that explain the factors that determine Mean Arterial Blood Pressure (MABP).

 

Recall that the other important factor affecting blood pressure is blood volume. This pictorial explanation of the same factors is from Amerman, 2^nd Ed., p 727:

 

 

A full explanation of each factor was provided on MyLO in section “2.2 Cardiovascular Physiology”. At the end of the section you had to choose one factor from each of the four rows in the set of formulae and explain its meaning in your own words.

 

Let’s start by discussing your completed table with your peers to gain a common understanding of the factors affecting MABP.

Factor	Name	How do I explain it?

 

 

For the following brief scenarios, explain how the physiology of the individual has been altered, which factor has been modified, and how it has affected her/his blood pressure.

Factor modified:

Cause and mechanism:

 

Effect on MABP:

Factor modified:

Cause and mechanism:

 

Effect on MABP:

Factor modified:

Cause and mechanism:

 

 

Effect on MABP:

Activity 2: Targets of Anti-hypertensive medication 

Aim: to explain the mechanisms of action of major anti-hypertensive drug classes: ACE inhibitors or Angiotensin Receptor Blockers (ARB), Beta-blockers, Calcium channel blockers and Diuretics 

 

The following figure from your textbook represents how the two control systems (nervous and endocrine), the renal system, and vasoactive substances contribute to the control of blood pressure.

Note – vasoactive substance are chemicals in the body which affect blood vessel smooth muscle. Can you name 2?

 

 

In your work as a nurse you will administer a lot of anti-hypertensive medication, and as with all medications, it is imperative that you know how they work. Using information from section the Australian Medicines Handbook (https://amhonline.amh.net.au/), indicate in the diagram the exact place in which the following classes of antihypertensive medication exert their action. In the table below, briefly explain how they contribute to lowering MABP using the formulate in Activity 1:

1. ACE inhibitors
2. ARBs
3. Beta-blockers
4. Calcium-Channel blockers
5. Diuretics

 

 

Drug Class	Site of Action	Mechanism
ACE* inhibitors
ARBs
Beta-blockers
Calcium Channel Blockers
Diuretics

 

 

Activity 3: Chronic and Acute Coronary Artery Disease

 

Aim: to discuss the risk factors and pathophysiology and treatment of chronic ischaemic heart disease and acute coronary syndrome

 

 

Rupinder was diagnose with stable angina. In your own words, explain what stable angina is and what is the most common cause of it.

 

 

 

 

 

From the scenario, identify the risk factors that Rupinder presents for the development of cardiovascular disease.

 

 

 

 

 

 

Rupinder has been recommended to stop smoking, reduce stress and exercise more frequently. How do these three lifestyle interventions reduce the risk of CVD?

 

 

 

 

 

Using the information on the Australian Medicines Handbook, explain the mechanism of action of the GTN (glyceryl nitrite) spray. When should Rupindra use the GTN spray? Should he inhale it?

 

 

 

 

 

 

 

 

Rupinder is diagnosed with an Anterior AMI (Acute Myocardial Infarction). Explain the progression from stable angina.

 

 

 

 

 

 

 

What is the rational for doing an ECG? Draw the modification of the following ECG trace that would lead the medical officer to diagnose a STEMI.

 

 

 

 

Explain the reason why Rupinder would have elevated levels of Troponin T.

 

 

Explain the therapeutic rationale and mechanism of action of the interventions indicated for Rupinder:

1. Continuous ECG monitoring:
2. Oxygen:
3. Aspirin:
4. GTN spray:
5. Morphine:
6. Clopidogrel

 

 

 

Activity 4: Chronic Heart Failure

Aim: to discuss the pathophysiology and treatment of chronic heart failure

 

 

 

Mr Larsson is diagnosed with acute heart failure. With your own words, explain what acute heart failure is and how it is related to the MI that he suffered a year ago.

 

 

 

 

 

Mr Larsson refuses to lay down flat because he feels that he cannot breathe. What is the reason for this? Explain the pathophysiological mechanism for this observation.

 

 

 

 

 

Mr Larsson presents 3+ pitting oedema of feet and ancles.  What other observations are related to this? What effect would this have on his blood pressure?