9. b. Arrhythmias Flashcards
Name 2 bradyarrhythmias
Sick sinus syndrome: SA node malfunction
Heart block: AV node malfunction
How can sick sinus syndrome be seen on an ECG?
Missed beats
How can heart block be seen on an ECG?
PR interval bigger than 1 box
Which ECG leads is the P wave best seen in?
2, 3, AVF, V1
How should heart block be managed?
Treat the underlying conditions
Discontinue drugs that reduce heart rate
Atropine or dopamine in unstable patients
Pacemaker in complete block
What does paroxysmal mean?
Short burst
What does a sustained tachycardia mean?
Lasts longer than 30 seconds
Requires intervention to stop
What does a non-sustained tachycardia mean?
Less than 30 seconds
Will self-terminate
What does a recurrent tachycardia mean?
Occurs periodically
More time non-tachycardic than tachycardic
What is atrial fibrillation?
Atrium is beating 400-600 BPM
Irregularly irregular conduction to AV node
How can atrial fibrillation be seen on an ECG?
No distinct p waves
QRS usually narrow
May have fibrillatory waves: baseline is jagged
What are the cornerstones of atrial fib management?
Avoid a stroke Control symptoms (rate and rhythm Reduce CV risks
What score is used to stratify the risk of stroke in non-valvular atrial fib?
CHADS2VASc
What drugs are given in non-valvular atrial fib?
Warfarin or DOACs
What is valvular atrial fib?
Atrial fib with mitral stenosis or an artificial valve
What drug is given in valvular atrial fib?
Warfarin to avoid thromboembolism from valves
What drugs are given for rate control in atrial fib?
B-blockers, Ca channel blockers
Digoxin
Amiodarone if all else fails
When is rhythm control introduced into the management of atrial fib?
Only if the patient is symptomatic and not fixed by rate control
How is rhythm control carried out in atrial fib?
Chemical or synchronised electrical cardioversion
What are the risk factors for atrial fib?
Hypertension, heart failure, coronary artery disease Diabetes, hyperthyroidism Sleep apnoea Electrolyte imbalances High alcohol or caffeine intake
What is atrial flutter?
Atrial rate 250-320 BPM
How can atrial flutter be seen on ECG?
Regular ‘saw tooth’ pattern
Narrow QRS
Where does supra-ventricular tachycardia originate?
AV node
How can supra-ventricular tachycardia be seen on ECG?
RAte 150-230 BPM
Narrow QRS
Absent P waves
ST may be depressed
How is supra-ventricular tachycardia managed?
Vagal manoeuvres to increase parasympathetic tone
Adenosine to block AV conduction
Electrical cardioversion if unstable
How can Wolff Parkinson White syndrome be seen on an ECG?
Short PR
Delta wave (notch on the upstroke of QRS)
Broad QRS
How is ventricular tachycardia seen on ECG?
Lots of broad QRS
Rapid HR
What is ventricular tachycardia?
Caused by a re-entry pathway in the ventricles
What are the causes of ventricular tachycardia?
Ischaemic heart disease
Cardiomyopathy
How is stable ventricular tachycardia managed?
Antiarrhythmic
Synchronised electrical cardioversion
Treat underlying cause and monitor
How is unstable ventricular tachycardia managed?
synchronised electrical cardioversion and antiarrhythmic
How is pulseless unstable ventricular tachycardia managed?
CPR
Unsynchronised defib
Adrenaline and amiodarone
How is ventricular tachycardia managed longterm?
Implantable defib
What is polymorphic ventricular tachycardia/ torsade de pointes?
QRS changes shape and axis
what condition causes polymorphic ventricular tachycardia?
MI
What condition causes torsade de pointes?
Long QT syndrome
What is ventricular fibrillation?
Rapid irregular ventricular contraction resulting in reduced CO
Fatal unless immediately acted upon
What are the causes of ventricular fibrillation?
MI
PE
Drowning
Electric shock
How is ventricular fibrillation treated?
CPR
Defib
Adrenaline
Amiodarone
What is long QT syndrome?
Abnormality of Na and/or K channels
Susceptible to Torsade de pointes
Can be drug induced
