1. Cardiology Flashcards
Explane phase Zero of the cardiac action potential
Fast sodium channels open and a rapid influx of Na enters the cell causing the cell to become less negative.
This is known as the upstroke
Explane phase one of the cardiac action potential cycle
Fast sodium channel gates close reducing the amount of Na+ that can enter. Cl- - enters the cell while K+ leaves makeing the cell more negatvie.
Explain phase Two of the cardiac action potential cycle
Both sodium and potassium enter and leave the cell at the same rate leaving the rate leaving the cell at the same electrical charge.
This is known as the plateau stage.
Explane phase three of the cardiac action potential cycle
Potassium rapidly leaves the cell leading to the cell becoming more negativly charged and bringing the cell down to its resting membrane potential
Explain phase four of the cardiac action potential cycle
Normal movements of ions into and out of the cell leaving the fell at its resting potential.
What are the Waves and complexes of an ECG
P Wave
PR interval
QRS complex
ST segment
J point
T wave
Whats the normal duration of the PRI
0.12-0.2 seconds
Normal duration of a QRS Complex
0.06-0.12 seconds
Whats the 5 Step ECG method
- Rate
- Regularity
- P wave
- PR Interval
- QRS Complex
What is the NSW Ambulance protocol for narrow complex tachycardias
- Pt symptomatic with SVT (narrow complex) ➡️ YES
- Pt LOC = A or V ➡️ Yes
If yes valsalva manoeuvre repeat once if not successful then transport. - Pt LOC =A or V ➡️ No
Synchronised cardioversion
1st shock 100j
2nd shock 150j
3rd shock 200j
Reassess after each shock (rapid ABC)
What are the three contrindications for syncronised cardioversion
1- pt LOC is A or V
2- pt less than 1
3- pt indicating sinus tachycardia, Rapid AF, Atrial Flutter
What does Paroxysmal mean?
Abrupt onset and abrupt termination
What heart rate is the difference for SVT and Sinus tachycardia?
Less than 150bpm equals sinus tach
Greater than 150bmp equals SVT
Mechanism of action for Adenosine?
Stimulates A1 adenosine recpeter and opens ACh senstive K+ channels. By inhibiting Ca+ channels leads to a slower conduction through the Atrioventricular node.
Victoran protocol for adenosine
Eg indications, dose, contraindications
6mg:2ml
Indications- SVT
Dose- 6mg IV
12mg IV if no reversion after two minutes
12mg IV if no reversion after two minutes
Contraindications-
AF,
Atrial Flutter
Ventricular rhythms
2nd or 3rd AV block
Describe the workings of the Valsalva maneuver
Pushing on a closed glottis increases intrathoracic pressure, opening of the airway decreases intrthoracic pressure now an increase in venous return increaces transmural pressure (pressure within the right atria) stretches the aorta stimulating baroreceptors activating a reflex vagus nerve stimulation leading to a reflex bradycardia.
Whats the following rhythm
SVT
Whats The Following rhythm
SVT