Week 5 - Cardiology Flashcards
(127 cards)
What is a clinical trial?
The evaluation of a new therapeutic intervention (i.e. drug, device, procedure) in human volunteers.
Describe the pathway of an action potential as it passes throughout the heart.
SA node>atrial muscle>AV node>common bundle>bundle branches>purkinje fibers>ventricular muscle.
A normal QRS axis is -30 to +90 degrees. How can you tell if there is a normal QRS axis on an ECG?
There should be a positive deflection in leads I and II.
A right axis deviation is +80 to +180 degrees. How can you tell if there is a right deviation on an ECG?
Predominantly negative deflection in leads I and aVL.
A left axis deviation is -30 to -90 degrees. How can you tell if there is a left axis deviation on an ECG?
Predominantly negative deflection in leads II and aVF.
Which leads on an ECG show the electrical activity from the anterior aspect of the heart?
Chest leads V1-V4
Which leads on an ECG show information about the electrical activity from the lateral aspect of the heart?
Chest leads V5 and V6 and limb leads I and aVL.
Which leads on an ECG show information about the electrical activity from the inferior aspect of the heart?
Limb leads II, III and aVF.
What is the difference between a STEMI and an NSTEMI?
A STEMI is caused by complete block of coronary flow.
An NSTEMI is caused by partial block of coronary flow.
Sometimes you can have ST elevation but it is not a myocardial infarction. How would you be sure that it is an MI?
If there is ST elevation in the anterior leads and reciprocal ST depression in the inferior leads.
What does a chest X-ray allow you to visualise on the heart?
Cardiac silhouette - size and position of the heart Great vessels Pulmonary vessels Pulmonary Oedema Pleural effusions
What can an echo doppler show you that a normal echo wouldn’t?
Flow of blood through the heart.
What is a transoesophageal and transthoracic echo?
Transoesophageal is when an ultrasound probe is placed down the throat and the heart is view through the oesophagus.
Transthoracic is when the probe is placed on the chest.
What can be assessed on an echocardiogram?
Heart structure and function, valves, pericardial assessment and inducable ischaemia.
What are the pros and cons of an echocardiogram?
Pros - cheap, available, no radiation, portable.
Cons - requires good acoustic window (good place to place probe for best image), user dependent.
What is the aim of functional stress testing?
Induce ischaemia by increasing the workload of the heart.
How is nuclear perfusion imaging performed? What does is allow you to assess?
Patient takes radioactive tracer and scanned using PET or SPECT, shows perfusion of the heart.
Assess ischaemia and ejection fraction.
What is ejection fraction?
The percentage of blood that is pumped into circulation with each ventricular contraction.
What are the pros and cons of nuclear perfusion imaging?
Pros - availability
Cons - radiation, no structural assessment
What is cardiac CT useful for?
Detecting coronary artery calcium which is a risk for CHD and also studying coronary anomalies i.e. single coronary artery.
What does cardiac CT allow you to visualise? What are its pros and cons?
Coronary artery anatomy and great vessel anatomy.
Pros - good ‘rule out’ for CAD, low risk
Cons - radiation dose, requires low heart rate, no functional assessment of ischaemia.
What is coronary angiography? What does it show?
Catheter inserted into femoral or radial artery and contrast medium injected in and X-ray imaged taken. Shows narrowing of coronary artery.
What are the indications for invasive angiography?
Ischaemia, primary PCI, valve assessment, assessment of ventricular pressure.
What are the pros and cons of invasive angiography?
Pros - gold standard, option for intervention during same procedure, availability.
Cons - radiation, risks - CVA, MI, contrast reaction, bleeding.