MODULE 7 - CHRONIC CARDIOVASCULAR CONDITION

Question 1

What is blood pressure?

Answer 1

A measurement of the ejection of blood from the heart during systole (contraction of the heart) and diastole (relaxation of heart)

Question 2

What is Systemic Vascular Resistance?

Answer 2

Affected by the tension or resistance of blood flow created by the walls of the arteries including the aorta, central and peripheral arteries

Question 3

What is the Mean Arterial Pressure?

Answer 3

The average pressure throughout the cardiac cycle

Question 4

What is hypertension?

Answer 4

Persistently high blood pressure (systolic bp greater than 140mmHg and diastolic bp greater than 90)

• Essentially, it’s a symptom or clinical manifestation of a range of clinical conditions.

Question 5

What is cardiac output? and what is the normal cardiac output level?

Answer 5

The amount of blood pumped by the heart each minute

- 4-6L/min

Question 6

What is the stroke volume?

Answer 6

The amount of blood pumped with each heartbeat

- approximately 70mls

Question 7

Explain the compensatory mechanisms for stroke volume

Answer 7

• If the SV decreases, the heart rate will increase

- If the heart rate is decreased, increased force of contraction will increase the SV

Question 8

What is the stroke volume affected by?

Answer 8

Preload
- the amount of stretch the myocardial fibres (heart muscle - at the end of diastole) and the resistance the left ventricle has to pump against (afterload) to push blood into the aorta

Therefore, the greater the volume delivered, the greater the amount of blood expelled, to a point.

Question 9

Explain the issues of myocardial tissue once it has been overstretched

Answer 9

Like a rubber band the further it is stretched, the more it will recoil. However like a rubber band, myocardial tissue has limits and like a rubber band once it has been overstretched it will not return to its normal shape. It will be larger and the walls will be thinner. The recoil is now reduced. The same can be said for the heart if it is damaged and becomes overstretched it remains so, reducing it’s pumping ability. When the heart pumps less blood forward, the body compensates by increasing the heart rate to p erfuse the body and vasoconstricting the peripheral vessels yo shunt blood to the major organs. So now the heart is working even hard, pumping harder and having to push blood against restricted vessels.

Question 10

Define heart failure

Answer 10

The failure to pump sufficient blood into the systemic circulation results in an inability to meet the bodies oxygen demands

• any condition that impairs the ability of the ventricles to fill or eject blood can cause Heart Failure

Question 11

What are the causes of Heart Failure?

Answer 11

Damage to the ventricular muscle (IHD/Myocardial Infarction)

• inflammatory/infective disorders (myocarditis/endocarditis)
• structural disorders (congenital heart defects/rheumatic heart disease)
• cardiomyopathies (hypertrophic obstructive cardiomyopathy/dilated cardiomyopathy)

Question 12

What is acute heart failure?

Answer 12

Sudden onset

• Symptoms;
• hypervolemia (excess fluid)
• sodium and water retention
• structural heart changes such as dilation and hypertrophy

Question 13

What is chronic heart failure?

Answer 13

Ongoing

• Symptoms;
• hypervolemia (excess fluid)
• sodium and water retention
• structural heart changes such as dilation and hypertrophy

Question 14

What is systolic failure?

and what are the causes and clinical manifestations?

Answer 14

Ventricle fails to contract adequately to eject sufficient blood volume into the arterial system

Causes: Ischemia, infarction, cardiomyopathy (enlarged heart) or inflammation

Clinical manifestations: weakness, fatigue, reduced exercise tolerance

Question 15

What is diastolic failure?

and what are the causes and clinical manifestations?

Answer 15

Heart cannot completely relax in diastole, disrupting filling

Causes: Reduced ventricular, compliance due to hypertrophy (enlargement) and impaired relaxation of muscle

Clinical manifestations:
SOB, tachypnoea, respiratory crackles if left ventricle affected
- distended neck veins, liver enlargement, anorexia and nausea if right ventricle affected

Question 16

What is left ventricular failure?

Answer 16

Failure of the left ventricle due to a disturbance of the contractile function of the left ventricle

• leads to vasoconstriction of the periphies

Question 17

What is systemic vascular resistance?

Answer 17

Impedes the delivery of blood from the left ventricle (increases after load)

• creating congestion and oedema in the pulmonary circulation and alveoli

Question 18

What are the clinical manifestations and late stages of left ventricular failure?

Answer 18

Clinical manifestations: decreased peripheral perfusion with decreased pulses, cool pale extremities and/or cyanosis, tachycardia, tachypnoea and crackles

Late stages (or acute onset): pulmonary oedema and accompanying haemoptysis (coughing up blood from lungs)

Question 19

What is right ventricular failure?

Answer 19

Ineffective right ventricular function (poor contractility of right ventricle)

• causes may be due to pulmonary embolus or right ventricular infarction

Question 20

What are the clinical manifestations of right ventricular failure?

Answer 20

peripheral and sacral oedema (pitting oedema), jugular venous distension, weakness, hepatomegaly (enlarged liver) or jaundice, poor appetite and nausea

Question 21

What are the pulmonary complications of heart failure?

Answer 21

Lung congestion is progressive and respiratory symptoms worsen as the heart failure increases

• initially SOB on exertion, as the condition worsens it may be at rest
• dyspnoea, orthopnoea (SOB lying flat) and paroxysmal nocturnal dyspnoea (attacks of severe SOB at night)

Question 22

What is acute pulmonary oedema?

Answer 22

Complication of heart failure
- fluid crossing from the capillaries into the alveoli due to high pressure in the lungs (pulmonary hypertension) inhibits gas exchange, leading to hypoxia

Question 23

What are the medications used for heart failure? Give an example for each

Answer 23

People with Heart Failure receive multiple medications it is not uncommon for them to have 2-3 medication charts. The aim of the medications is to reduce the cardiac workload and to improve cardiac function.

• ACE (angiotensin converting enzyme) inhibitors (‘pril’ perindopril and ramipril) and ARBs (angiotensin 2 receptor blockers) (‘sartan’ irbesartan, candesartan)
• Diuretics: frusemide (lasix), spironolactone
• Electrolyte replacements: magnesium and potassium
• Digoxin
• Inotropic agents: dobutamine, dopamine (usually critical care, but are sometimes commenced in ward environments)
• antiarrhythmics: amiodarone

Question 24

What is the purpose of ACE inhibitors and ARB’s?

Answer 24

ACE inbitors and ARB’s are prescribed to reduce mortality in heart failure. Although they work slightly differently, they both block the action of angiotensin II, a vasoconstrictor. This causes vasodilation which reduces afterload the pressure the right ventricle has to overcome to push blood forward it also increase renal perfusion, excess blood volume is therefore excreted as urine.

Question 25

What are the nursing responsibilities for ACE inhibitors and ARBs?

Answer 25

Nursing Responsibilities for this medication include regular monitoring of blood pressure and kidney function, (as it can cause further damage to patients with impaired kidney function) Checking urine output and blood results.

Question 26

What is the purpose of diuretics?

Answer 26

The Diuretics work on the kidneys to reduce reabsorption of sodium and water. Removes excess fluid during heart failure, this also reduces afterload. Spironolactone is a potassium sparing diuretic. Frusemide may require regular potassium monitoring due to excretion through urine, and potassium replacement commonly referred to as Span K. I have put the trade name Lasix (meaning last six hours, it is generally prescribed at 0600hrs and 1200hrs, 6 hours apart)

Question 27

What are the nursing responsibilities for diuretics?

Answer 27

Nursing responsibilities include monitoring FBC including input and output, daily weighs and monitoring electrolytes, particularly mgSo2 and potassium.

Question 28

What is the purpose of digoxin?

Answer 28

Digoxin can both regulate the heart, by slowing it reduces cardiac workload and this allows greater time for the ventricle to fill before contraction, meaning more will be ejected. It also causes a greater force of contraction. Increasing stroke volume.

Question 29

What are the nursing responsibilities for digoxin?

Answer 29

Nursing responsibilities including checking the pulse before administration and withholding and or notifying the doctor if the pulse is less than 60 beats per minute. Ensuring regular blood checks of electrolytes and monitoring digoxin levels.

Question 30

What is the purpose of inotropic agents?

Answer 30

Inotropic agents stimulate the heart improving the force of contraction, they are administered in acute episodes and are generally administered in a critical care area. These drugs are given intravenously and have a very short half-life, therefore cannot be stopped abruptly. Patients require regular observations and constant cardiac monitoring whilst receiving Inotropes. Dobutamine works on Beta 1 and Beta 2 receptors to increase contraction and relax (dilate) smooth muscle to improve cardiac output.

Question 31

What is required for the management of chronic HF?

Answer 31

- health promotion: cardiac rehabilitation - fluid restrictions - medication compliance - management of hypertension daily weigh - prescribed medications - low sodium diet - regular visits to GP and/or heart failure nurse/cardiac CNC - stool softeners - ongoing support and education

Question 32

What are the nursing cares provided in hospital in regards to HF?

Answer 32

- health promotion - assessment health history: physical examination and diagnostic testing - regular vitals: bp tor and o2 saturations (4th hrly breathing sounds) - cardiac monitoring (telemetry) - monitor fluid balance chart: chart input vs output - restrict fluids as ordered - daily weigh - prescribed medications - low sodium diet - elevate head of bed >30 - ADL's: provide adequate support and rest periods - stool softeners - ongoing support and education

Question 33

What is the ECG waveform?

Answer 33

The ECG complex represents the electrical events occurring in one cardiac cycle. A complex consists of five waveforms labelled with the letters P, Q, R,S,T - the middle three letters: Q,R,S are referred to as the QRS complex

Question 34

What are the components of the conduction system?

Answer 34

The impulse originates in the Sinoatrial Node (SA), electrically this is represented as a P wave (atrial depolarisation) as it passes through the atrium, the atrium contracts - it reaches the atrioventricular (AV) node, where it is slowed, before passing onto the Bundle of His - the impulse reaches the purkinje fibres, stimulating the ventricular myocardial cells (ventricular depolarisation) represented as QRS complex, ventricular contraction occurs - The T wave represents ventricular depolarisation, return of the stimulated muscle to a resting state

Question 35

What are the components of a rhythm?

Answer 35

P WAVE (ATRIAL DEPOLARISATION): impulse from the SA node through the 2 atria, right to left QRS COMPLEX: Ventricular depolarisation, impulse traveling through the purkinje fibres of the ventricle ST SEGMENT: Time between the end of depolarisation and depolarisation of ventricles. a raised/depressed ST segment may be indication of myocardial infarction/ishemia T WAVE: Ventricular depolarisation return of stimulated muscle to a resting state

Question 36

What are the hearts inherent pacemakers? Explain

Answer 36

- SA NODE 60-100BPM (SINUS) - AV NODE 40-60BPM (JUNCTIONAL) - PURKINJE FIBRES 15-40BPM (VENTRICULAR)

Question 37

How are rhythms classified?

Answer 37

Point of origin (atrial, sinus, junctional, ventricular and heart block) and their rate (bradycardia, tachycardia) or pattern (fibrillation)

Question 38

What are the characteristics of the 'normal' sinus rhythm?

Answer 38

- regular rhythm - normal HR (60-100bpm) - P wave for every QRS complex and all P waves appear the same - all QRS appear the same - normal T waves

Question 39

What are the characteristics of the junctional rhythm?

Answer 39

- regular rhythm - rate 40-60bpm (inherent rate of AV node, the SA node is not the inherent pacemaker) - absent P waves, inverted or after QRS - all QRS's appear the same - normal T waves - treatment: only if asymptomatic; medications to increase HR - atropine

Question 40

What are the characteristics of the idioventricular rhythm? | including treatment

Answer 40

- regular rhythm - rate <40bpm (inherent rate of purkinje fibres, the SA/AV node is not the inherent pacemaker) - absent P waves, inverted or after QRS - all QRS's appear the same - normal T waves - Treatment: emergency due reduced cardiac output - code blue/notify medical staff

Question 41

What are the characteristics of sinus bradycardia in regards to ECG's? (including causes and treatment)

Answer 41

- regular rhythm - heart rate <60bpm - P wave for every QRS complex and all P waves appear the same - all QRS appear the same - normal T waves Causes: Hyperkalaemia, hypothermia, vomiting, cardiac disease, medications (beta-blockers, calcium channel blockers, digoxin) and fitness (athletes) Treatment: if asymptomatic - no treatment if symptomatic - monitoring and medications (atropine). withhold any medications that maybe contributing

Question 42

What are the characteristics of sinus tachycardia in regards to ECG's? (including causes and treatment)

Answer 42

- regular rhythm - heart rate >100bpm - P wave for every QRS complex and all P waves appear the same - all QRS appear the same - normal T waves Causes: response to exercise, stress or pain. Heart failure, shock, bleeding/anaemia, respiratory distress, sepsis, medications (dopamine, illicit drugs) Treatment: if asymptomatic - monitor and explore/treat underlying cause if symptomatic - asses patient, find and treat the underlying cause cares

Question 43

What are the characteristics of atrial fibrillation in regards to ECG's? (including causes and treatment)

Answer 43

- irregular rhythm - heart rate: ventricular rate varies - P wave not discernible/visible, fibrillary waves Causes: Rheumatic Heart Disease, Ischemic Heart Disease, Thyrotxicosis, Hypertension Treatment: assess patient, if HR is fast, may need prompt treatment with medication (digoxin/amiodarone). consider anticoagulation

Question 44

What are the characteristics of ventricular tachycardia in regards to ECG's? (including problem and treatment)

Answer 44

- regular rhythm - HR >100bpm - no visible P waves - QRS wide and abnormal Problem: the rapid rate will compromise cardiac output, heart does not have enough time to fill with blood and eject it out to perfuse the body Treatment: assess patient; if patient is unconscious; basic life support and treatment is immediate defibrillation

Question 45

What are the characteristics of ventricular fibrillation in regards to ECG's? (including problem and treatment)

Answer 45

- irregular chaotic rhythm - HR indiscernible only fibrillatory waves present - no visible P waves - QRS wide, bizarre, irregularly shaped fibrillation waves Problem: nil cardiac output Treatment: assess patient; if patient is unconscious; basic life support and treatment is immediate defibrillation

Question 46

What are the characteristics of asystole (no rhythm) in regards to ECG's? (including treatment)

Answer 46

- HR 0 - no identifiable electrical activity 'flat line' Treatment: assess patient, code blue, commence basic life support. asystole is a 'non-shockable rhythm'.