Week 2 ECG Flashcards
(29 cards)
What is sinus tachycardia? Describe the ECG
Regular fast HR
Same distance between each part of the wave. >100bpm.
What is sinus bradycardia? Describe the ECG
Regular slow HR <60bpm.
Same distance between each wave just not as many per second.
Describe sinus arrhythmia? What can cause it?
2 fast, one slow heartbeat = regular, not normal.
Can be due to breathing, breathing in increases HR, breathing out decreases HR.
Regularly irregular pattern.
What are premature ventricular contractions (PVCs)?
Extra or missed beats caused by a group of cells in the ventricles that cause an early beat.
They don’t normally require investigation. May cause palpitations and a sense of the heart “skipping a beat”.
What is a unifocal PVC?
When the extra beats both looks the same.
The heart is generating 2 extra beats from the same place - not to worry about.
Can be caused by too much caffeine.
what are Multifocal PVCs?
Multiple extra beats that look different.
More concerning.
Coming from different places to each other.
What is bigeminy?
Every other beat is an extra one.
What is trigeminy?
Every third beat is an extra one.
What does more than 3 PVCs in a run indicate?
What does the ECG look like?
Ventricular tachycardia (non-sustained) = VT.
Normal ECG beats followed by larger QRS complex - ventricular contractions.
What is the issue with sustained VT?
It is ventricular fibrillation (VF).
Does not allow the ventricles to fill so can’t maintain cardiac output.
What is atrial fibrillation? How can you identify it?
Rapid and chaotic depolarisation within the atria.
No P wave on the ECG.
Increases risk of thrombosis/embolism (blood clot) - causes 20% of all strokes.
How to identify wolf parkinson white syndrome? What is it?
Very short PR interval (0.08s) - speeds everything up.
The electrical impulse bypasses the AV node.
Pre-excitation syndrome.
How to identify atrioventricular blocks
How are they sometimes treated?
Longer PR intervals - slows everything down.
if 2nd or 3rd degree block may be fitted with a pacemaker.
Right bundle branch block
How to identify?
Issues?
What happens
M shape in the QRS of V1 and W in V6 - MARROW
Fairly common in athletes, doesn’t really cause any major issues or symptoms.
Signal affected goes to the right ventricles from the bundle of His
Left bundle branch block
How to identify?
Issues?
What happens?
Tall R waves in V5-V6, deep S waves in V1-3.
W in V1, M in V6 QRS - WILLIAM
Do not exercise if you have this, if blockage is in left ventricle oxygen won’t be getting to the body - danger for exercise.
RV depolarises normally and first via RBB, delayed activation of LV as must be depolarised by the RBB with depolarisation from R to L.
Left ventricular hypertrophy
When to expect?
Issues?
What does the ECG look like?
Athletes, thin chest walls (not much space between heart and electrode makes voltage seem higher than it is). Uncontrolled, long lasting hypertension and aortic stenosis (narrowing of heart valve) - left ventricle has to thicken to pump blood as at higher pressure.
Often considered normal in athletes.
Thickened walls leads to prolonged depolarisation (R) and delayed repolarisation (ST and T in lateral leads).
How to identify myocardial ischemia?
What suggests it is a blockage of the left main coronary artery?
ST depression >1mm. Leads II, III and V4
T wave inversion (flattening) can be seen but not always.
Widespread ST depression across multiple leads.
How to identify myocardial infarction?
ST elevation (STEMI = ST elevated MI).
When is medical clearance needed?
Known disease but no symptoms.
Any signs or symptoms suggestive of disease.
If cleared they can progress from light to moderate exercise.
Who should be supervising different patients.
Low risk - no-one, safe to exercise alone.
Medium risk - a HCP with exercise testing experience
High risk - a HCP with exercise testing experience, doctor must be immediately available (ILS trained for administration of drugs if CV event).
What are some contraindications to exercise?
Unstable anything e.g. angina, diabetes, arrhythmia, tachycardia.
Resting SBP> 180/200
Resting DBP > 100/110
Symptomatic Hypotension
Acute infections
Heart disease
What is phase 0?
Rapid depolarisation
Na+ channels open for rapid influx of Na.
Phase 1
Rapid depolarisation
Na channels close/become inactivated - no Na influx.
K+ channels open for brief K+ influx then close rapidly.
Phase 2
Plateau (longest phase)
Influx of Ca2+ - released from sarcoplasmic reticulum to initiate contraction
K+ efflux (causes plateau)
