Cardiac Flashcards
List ways of stopping SVT?
Valsalva manoeuvre.
Blow into syringe.
Placing face in ice cold water.
Suck on ice cubes.
Cardioversion.
Catheter ablation.
What causes re entrant SVT?
Reentrant supraventricular tachycardias (SVT) involve reentrant pathways with a component above the bifurcation of the His bundle.
How might beta-blockers affect pts with severe haemorrhage?
Beta-blockers such as propranolol and atenolol block the activity of the sympathetic nervous system so pts may not develop a tachycardia in response to significant haemorrhage. (Used for angina and hypertension.)
What effect will a fever have on the heart rate?
Increases in core temp increases rate of SA node depolarisation. Hypothermia causes bradycardia.
What affect does atropine have on the heart?
Blocks the vagal nerve activity (which at rest, works to slow the the SA node). Hence used for bradycardia.
Three main causes of dysrhythmia are:
Altered automaticity, re-entry and triggered activation.
What is fibrillation?
Fibrillation is the rapid, irregular, and unsynchronized contraction of muscle fibers. An important occurrence is with regard to the heart.
If lead I is positive and aVF is positive then axis deviation is?
Normal
If lead I is positive and aVF negative axis deviation is?
Left
If lead I is negative and aVF positive axis deviation is?
Right
If both lead I and aVF are negative then axis deviation is?
Extreme
How long is the P Wave and what is it?
Represents the depolarisation of the atria and is normally less than 0.1 seconds and less than 2.5 mm tall.
How long is the small box on an ECG?
0.04 seconds
How long is a big box on the ECG?
5 small boxes 0.2 seconds
How long is the qrs complex?
Less than 0.12
What does the qrs complex represent?
The depolarisation of the ventricles.
What are Q, Rand S waves?
Q wave is deflection before R wave.
R wave is any positive deflection.
S wave is any negative deflection after R wave.
What does the T wave represent?
Repolarisation of ventricles.
What does the PR interval represent and how long does it last?
Between 0.12 and 0.2 secs and time taken for impulse generated in SA node to reach the ventricles via AV node and bundle branches,
Seven steps of ECG analysis are?
HR Rhythm P waves QRS PR interval T wave ST segment
Always suspect a posterior MI if?
ECG shows tall R waves or ST dep in V1 and V2 especially if inferior MI suspected.
How do we confirm ET placement?
Direct vision
Auscultation
Waveform capnography
What is the Levine Sign?
Clenched fist over chest.
