Arrythmias Flashcards
What is normal sinus rhythm?
60-100bpm
What is normal p wave?
0.5-2.5mm tall
What is normal PR interval?
0.12-0.2 secs
What is normal QRS complex?
<0.12secs
What is normal QT interval?
<0.42 secs
What is normal T wave?
0.1-0.25 secs
What is normal ST segment?
0.08 secs
What are the four cardiac arrest rhythms?
Shockable:
- Ventricular tachycardia
- Ventricular fibrillation
Non-shockable:
- Pulseless electrical activity
- Asystole
What are the types of tachycardia?
Sinus tachycardia
Supraventricular tachycardia
Wolf Parkinson White syndrome
Atrial flutter
Atrial fibrillation
Ventricular tachycardia
Torsade’s de pointes
Ventricular fibrillation
What is SVT?
Electrical signal re-enters the atria from the ventricles
Narrow QRS complex
- AV nodal re-entry: re-entry back through AV node
- AV re-entry: re-entry via accessory pathway (WPW)
- Atrial tachycardia: electrical signal originates in atria somewhere other than SA node
What is WPW syndrome?
Caused by accessory pathway connecting atria and ventricles called the Bundle of Kent
Short PR interval
Wide QRS complex
Definitive treatment is radiofrequency ablation
What is torsades de pointes?
Polymorphic ventricular tachycardia
Occurs in patients with a prolonged QT interval
Twisting and progressive change in amplitude of the QRS complexes
What are the types of heart block?
First degree
Second degree
Third degree
Right bundle branch block
Left bundle branch block
What is first degree heart block?
Delayed conduction through AV node
Prolonged PR Interval
What is second degree heart block?
Excitation intermittently fails to pass through AV node
What are the patterns of second degree heart block?
Mobitz type 1 (Wenckebach’s phenomenon)
Mobitz type 2
What is mobitz type 1?
Progressive lengthening of PR interval and eventual failure of conduction of atrial beat then cycle repeats
What is mobitz type 2?
Intermittent failure of AV conduction causing missing QRS complexes
Risk of asystole
What is 2:1 block?
2 p waves for each QRS complex
Caused by mobitz heart block
What is third degree heart block?
Complete heart block
No relationship between P waves and QRS complexes
Significant risk of asystole
What is RBBB?
Ventricles depolarise consecutively instead of simultaneously
Wide QRS complexes
What is LBBB?
Ventricles depolarise consecutively instead of simultaneously
More influence on ECG
What is the classification of treatments?
Vaughan William’s classification
- I: Na+ channel blockers
- II: Beta blockers
- III: K+ channel blockers
- IV: Ca2+ channel blockers
- V: other antiarrhythmics
What are Na+ channel blockers?
Ia (moderate)- quinidine
Ib (weak)- lidocaine
Ic (strong)- flecainide
What are Beta blockers?
Atenolol
Bisoprolol
Propranolol
First line in AF
What are K+ channel blockers?
Amiodarone
What are Ca2+ channel blockers?
Verapamil
Diltiazem
What is the action of digoxin?
Cardiac glycoside
Blocks Na+/K+ ATPase pump
What is the action of adenosine?
Blocks AV node
When are anticoagulants given?
Atrial fibrillation
Warfarin
What are types of anticoagulants?
Vitamin K antagonists- warfarin
Thrombin inhibitors- dabigatran
Factor Xa inhibitors- apixaban, edoxaban
What is atrial fibrillation?
Contraction of atria is uncoordinated, rapid and irregular
Absence of P waves
What are the symptoms of AF?
Palpitations
SoB
Syncope
Irregular;y irregular pulse
What does AF look like on ECG?
Absent p waves
Narrow QRS complex tachycardia
Irregularly irregular ventricular rhythm
What are the main causes of AF?
Sepsis
Mitral valve pathology
Ischaemic heart disease
Thyrotoxicosis
Hypertension
What is the principles of treating AF?
Rate control
Rhythm control
Anticoagulation to prevent stroke
What is CHA2DS2VAS score for AF?
AF stroke risk
Congestive heart failure
Hypertension
Age>75
Diabetes
Stroke history
Vascular disease
Age 65-74
Sex (female)
