Cardiac Conditions Flashcards
How can an arrhythmia occur?
Heart block occurs when conduction of impulses is blocked.
- diagnosed on an ECG, telling us how much of the signal is interrupted
Ectopic pacemaker - an excitable focus outside the normal SA node
- extra tissue is firing in the SA node
Premature ventricular contraction (PVC) - occurs when an ectopic pacemaker initiates a beat
- the heart contracts early then it should
Explain what an arrhythmia is and it’s two categories.
An arrhythmia represents the disorder of a cardiac rhythm.
Supraventricular arrhythmia
- generated in the SA node, AV node and junction all tissue
Ventricular arrhythmia
- generated in ventricular conduction system and ventricular muscle
What is the main cause of coronary heart disease (CHD), and the most frequent cause of?
Atherosclerosis
- most frequent cause of myocardial infarction (MI) and sudden death.
Why does CHD not produce symptoms until it is well advanced?
Collateral channels develop at the same time as the atherosclerotic changes are occurring.
What are the most common places for atherosclerotic lesions or atheromatous plaque to occur?
In the several centimetres of the left anterior descending and left circumflex, or the entire length of the right coronary arteries.
Explain the two types of plaque.
Fixed or stable plaque
- obstructs blood flow (stable angina)
- predictable
Unstable plaque
- can rupture and cause platelet adhesion and thrombus formation (unstable angina and MI)
- unpredictable
What are the two main types of CHD? Explain each.
Chronic ischemia heart disease
- chronic stable angina
- silent myocardial ischaemia
- prinzmental or variant angina
Acute coronary syndrome
- unstable angina
- myocardial infarct
Explain ischaemic heart disease.
- an imbalance between blood supply and cardiac demands for oxygenated blood
- usually due to atherosclerosis but vasospasm and thrombosis play a part
Explain stable angina.
Symptomatic chest pain or pressure due to transient myocardial ischaemia. Chronic stable angina is associated with coronary vessel obstruction and precipitated by situations that increase the work demands of the heart.
How is angina pain normally described?
- constricting
- squeezing
- suffocating
- steady pain, increasing in intensity at the onset and end of an attack
- located in the precordium, and may radiate to the left shoulder, jaw, arm or other chest areas.
Explain silent myocardial ischaemia.
- occurs in the absence of angina
- often seen in patients with diabetes
Variant angina is also known as ________.
Vasospasdic
Explain variant angina.
- caused by spasm of the coronary arteries
- usually due to coronary artery stenosis but an occur without evidence of disease
- usually occurs during rest or with minimal exertion, especially at night
- arrhythmias often occur when the pain is severe resulting in ST segment elevation
Explain unstable angina.
- pain is more persistent and severe
- characterised by at least one of the following thre:
= occurs at rest and usually lasts more than 20 minutes
= it is severe
= occurs in a pattern that is more severe prolonged or frequent than previously experienced
Explain acute myocardial infarction.
- characterised by the ischaemic death of myocardial tissue
- area of infarction is determined by the coronary artery affected and its distribution of blood flow
- onset is abrupt, pain is the most common symptom
- pain is severe and crushing, subset renal, radiating to the left arm, neck or jaw but may be atypical
