Cardiology Flashcards
What is a pulse?
Rhythmic expansion of an artery, which corresponds to each contraction of the left ventricle
What is the heart rate?
Speed of the heart contractions
What is stroke volume?
Volume of blood pumped out of the ventricles with each heart beat
What is total peripheral resistance?
The amount of force exerted on circulating blood by the vasculature of the body
What are the 3 factors that affect TPR/SVR?
Autonomic activity - sympathetic nervous system (vasoconstriction)
Blood viscosity - increased thickness of blood leads to increased TPR
Medications - vasoconstrictor and vasodilator drugs
What is cardiac output and how is it calculated?
The amount of blood the heart pumps each minute
Stroke volume X heart rate
What happens to cardiac output if the body needs more oxygen?
It will increase so that more oxygen is available throughout the body
It does this by increasing HR and SVR through vasoconstriction (this increases blood pressure)
What are the stages of the cardiac cycle?
Atrial systole
Ventricular systole
Diastole
What is an ECG?
A scan that records the electrical signals in the heart
Looks at heart rate, rhythm and electrical activity
Can indicate enlargement of the heart (cardiomyopathy) and evidence of a previous heart attack
Sensors attached to skin detect electrical activity
What can ECGs tell us?
Heart rate and rhythm
Abnormalities such as lack of P wave or arrhythmias (irregular beats)
Evidence of damage (MI/ischemia)
Raised, depressed, flipped or flat ST waves - evidence of ischaemic heart damage
What is blood pressure?
Blood pressure is a measure of the force that moves blood around your body
Generated by the heart beat
The force of blood pushing against the walls of your arteries is what is measured
What factors does blood pressure measurement involve?
Cardiac output
Total peripheral resistance
How is blood pressure controlled in the short term?
Via the baroreceptor receptors found in the carotid sinus and the aorta
Changes in blood pressure, and vasoconstrictor or dilate vessels as required - innervates the parasympathetic nervous system (vasodilation and slow HR) or sympathetic nervous system (vasoconstriction and increase HR)
How is longer term blood pressure controlled?
Renin-Angiotensin-Aldosterone System (RAAS)
A hormonal system that controls BP
What are the stages of the RAAS?
Renin
Angiotensin 1
Angiotensin 2
Aldosterone & ADH
Where is renin released from?
The kidneys into the blood
Where is angiotensin released from?
The liver
What happens to angiotensin 1 (AT 1)?
Converted into AT 2 via ACE (angiotensin converting enzymes) in the lungs and kidneys
What does angiotensin 2 (AT2) do?
Binds to AT2 receptors on tissues to elicit a response
Stimulates the release of ADH and aldosterone
What does RAAS do?
Causes systemic vasoconstriction
Angiotensin 2 stimulates aldosterone release which causes a thirst response and reduces urine output (causes more fluid to be retained within the system) increasing BP and cardiac output
How can RAAS be a problem?
Overactive or inappropriately activated RAAS is a cause for hypertension
How can hypertension be treated by targeting RAAS?
ACE inhibitors and angiotensin receptor blockers are common treatments for hypertension
Nurses must be aware of the action of anti-hypertensive medications and ensure that patients BP is stable prior to administering treatment
What does hypertension mean?
High blood pressure
What does hypotension mean?
Low blood pressure
What does normotension mean?
Normal blood pressure
What does postural hypotension mean?
A drop in blood pressure when you stand up after lying or sitting down
What is malignant hypertension?
Dangerously high blood pressure
How does hypertension affect the heart?
Reduces elasticity
Reduces muscle function of arteries
Can cause the muscular walls of the ventricles to become thick and stiff - can lead to heart failure
Heart attack (MI)
How can hypertension lead to heart failure?
The constant increased pressure against the walls of the heart can cause them to stretch and either become stiff or baggy
This leads to the heart pumping less effectively and in severe cases can lead to heart failure - heart is unable to meet the needs of the body for an increase in CO
What is Acute Coronary Syndrome (ACS)?
Reduced blood flow to the heart - could be caused by a blockage or a spasm of the vessels
WHat symptoms does Acute Coronary Syndrome cause?
Chest pain (angina) worsened on exertion
Nausea
Sweating/shivering (cold/grey/clammy)
Referred pain (jaw/left sided chest pain) - women often report indigestion or no chest pain
Severe indigestion
Shortness of breath
What is coronary heart disease (CHD)?
Hearts blood supply is blocked or interrupted by a build-up of fatty substances in the coronary arteries - could be a fatty plaque blockage or a blood clot
Can lead to a myocardial infarction
What is angina?
Pain or discomfort in the chest, arm, neck, stomach or jaw that happens when the blood supply to the heart becomes restricted because of arteries becoming narrowed (atheroma)
Hearts way of saying its not getting enough oxygen due to increased activity requiring an increase in CO
Symptom of CHD (not an illness in itself)
What is unstable angina?
Where angina symptoms occur not related to an increase in activity and can be an indication of ACS
What are arrhythmias?
Irregular heart beats - can occur naturally but irregular heart rates can often be a sign or symptom of underlying illness or disease
What is Atrial Fibrillation (AF)?
Where disease or damage to the atria has caused the atrium to beat irregularly and inhibit filling and emptying
Increases risk of developing thrombosis
What is SupraVentricular Tachycardia (SVT)?
Can be a life-threatening condition where the ventricles are stimulated to beat faster than normal (120-220bpm)
What causes SVT?
Can be caused by anxiety/stress or other stimulants but if it does not resolve quickly then it can be life threatening
Occurs due to damage or irritation of the SA node and causes abnormal stimulation of the cardiac muscle relating in a significantly fast arrhythmia
What is Ventricular Tachycardia (VT)?
Causes the ventricles to beat fast (160bpm+)
Insufficient time for cardiac filling to occur and means that CO falls and therefore the amount of oxygen pumped to the body and brain falls
What is Ventricular Fibrillation (VF)?
Where the ventricles are unable to beat correctly leading to insufficient filling and emptying
Ventricles fibrillate (wobble) so are unable to pump and therefore the heart and the rest of the body is starved of oxygen - Cardiac Arrest
What are the risk factors for heart conditions?
Obesity (especially visceral fat)
High cholesterol (hypercholesterolemia)
High blood pressure (hypertension)
Inactivity
Smoking
Diabetes
Family history
Sex
Age
Sleep apnoea
Stress
Diet
What is the role of a general nurse for patients with heart conditions?
Lifestyle advice/risk factor modification
Medication advice
Reassurance
Rehabilitation
What is the role of a specialist nurse for patients with heart conditions?
Managing case load of patients with cardiac conditions
Booking and interpreting scans and diagnostic tests
Supporting patients in living with new diagnosis or ongoing illness
Health promotion
