cardiac arrhythmias Flashcards
what are the two groups of cardiac arrhythmias?
tachy arrythmias - too fast
Brady arrhythmias - too slow
What may cause Brady arrhythmias ?
- drug induced by beta blocker or digoxin
- heart block
what type of cardiac arrhythmia is associated with postural change issues?
Brady
what is heart block?
reduction in impulse conduction from SA node to AV node
what will a prolonged p-q interval on ECG mean?
heart block
1st 2nd and 3rd degree depending on severity/length of signal delay with 3rd being total heart block
what rate will ventricles pulse at during complete heart block?
their own intrinsic rate of 30bpm
What is tachyarrhythmia ?
- impaired cardiac function by reducing diastolic filling time
- reduced cardiac output leads to heart failure
describe atrial tachy arythmias.
- rapid atrial impulses conducted to ventricles giving high heart rate
- atrial fibrillation
describe ventricular tachy arrythmias.
-rhythm arises in ventricle and spreads through muscle fibres instead of bundle of his
-dangerous as can lead to
ventricular fibrillation and death
describe the ECG of atrial fibrillation.
- hard to identify p waves
- irregularly irregular pulse
- no p waves as disorganised activity
- narrow QRS on ECG
- ECG may be normal but fast
describe the ECG of Brady arrhythmia
Broad QRS on ECG
what is a cardiac pacemaker used to treat?
Brady arrhythmias
what is ventricular tachyarythmia usually a precursor for?
ventricular fibrillation
what does asystole mean?
no cardiac output
no electrical activity
what will asystole look like on ECG?
wavy line
How is asystole treated?
- adrenaline to try cause electrical activity in heart for defibrillation
- cannot defibrillate alone as no electrical activity to reorganise
How does a pacemaker work?
- keeps heart rate at a minimal level
- paces heart if rate falls below certain level by activating muscle to cause contraction
- sensing circuit senses electrical activity
- pacing circuit activates muscle
how is a pacemaker fitted?
in the chest wall and wires are passed through blood vessels into ventricles
describe the sinus rhythms of ECG
P wave = atrial depolarisation
QRS complex = ventricular depolarisation
T wave = ventricular repolarisation
What are the theoretical risks of pacemaker?
electrical interference causing shutdown e.g. induction scalers as they use EM field,
MRI, electrosurgery and diathermy
what will a defibrillator impact do?
look for ventricular fibrillation and shock heart out of ventricular fibrillation rapidly
Describe ventricular defibrillation.
- unstable electrical heart activity with ventricle muscle fibres contracting at random
- no emptying of ventricles - >no cardiac output
- heart attack, long QT wave and wolf-parkinson-white syndrome
- treat with defibrillation
