Arrythmias Flashcards
What is an arrhythmia
Common problems in cardiology
Where the heart is dangerously too slow or too fast
What is the normal cardiac conduction
SAN —> atria cell to cell conduction —> AVN have the pause to ensure the contraction of the atria is complete
—> bundle of HIs into the right and left bundle branches to the ventricles which contract all together upwards forcing blood out into the vessels
ECG peaks associated with
P
QRS
T
P wave is the atria
P-Q interval is the AV delay
QRS ventricle contraction
T is the ventricle relaxation
What is atrial fibrillation
Affects 2% of the population Easily diagnosed 25% of 40 yo will go on to suffer from AF Increases the risk of stroke by 5% 20% of all strokes are due to AF
AF irregular heart rhythm QRS is narrow
No P waves
Disorganised activity in the atria = fast and rapid disorganised activity
Atria do not contract they quiver
What are the mechanisms of AF
Triggers tend to be at the pulmonary vein and the SVC
Junction between the 2 tissue types can lead to non functioning cell to cell communication
If you pace the heart you can induce AF in those susceptible
- valvular HD
- cardiomegly
Substrate Left atrial enlargement Fibrosis Rotors Electrical changes
Treatment of AF
Anticoagulation
Rate control
Anticoag can prevent 60%of strokes and reduces mortality by 25% if anticoagulated
Warfarin or DOAC
Warfarin need regular blood tests to check the INR to ensure the blood is not too thick or thin, diet changes or new drugs need to be careful as they can affect the drug.
DOAC no blood tests no known reversal agents
Rate control Slow the ventricular rate Aim for a resting HR of 60-80 Drugs Beta blocker or calcium channel blocker digoxin Often needs more than one
Sometimes drugs and ablation to restore normal rhythm
With rotate control no evidence that inc prognosis but helps with symptoms
What happens in atrial flutter
Right atrium activity goes round and round at a rate of 300
AVN cannot conduct to the ventricles fast enough so they contact on the 2nd 3rd time
Leads to a 2:1 or 3:1
150bpm 75bpm
Types of heart block
1st degree heart block
2nd degree heart block
Mobitz1 inc distance between Q wave and the a dropped beat
Mobitz2 no inc distance just dropped best
3rd degree complete heart block
What are pacemakers
They prevent slow heart rhythms
Some patient lace rarely these prevent syncope
Some all the time - they have slow heart rhythm
Some are pacing dependent and have no underlying rhythm
What is an ICD
Implantable cardiac defib
Prevent sudden cardiac death from ventricular arrhythmia
Non symptomatic benefit
The defibrillator detects normal heart rhythm if it goes too fast it initially tries to normalise it by pacing rapidly to regain control and then slow down
If it doesn’t work shock them
Types of SVT
ANRT - renewer at the node
AVRT - renter at an accessory pathway e.g. WPW
