Arrhythmias Flashcards
What is the PR interval?
Time taken for the spread of depolarisation from the SA node to the ventricular muscle through the AV node (<0.2s)
What is interference with the conduction called during the PR interval called?
Heart block
What does a prolonged PR interval imply?
Delay in conduction of the wave of depolarisation from SA node to the ventricles
What is a supraventricular extrasystole?
Atrial ectopic beat - P wave differs in shape from the P wave in sinus rhythm
What are risk factors for AF?
Age HPT HF Obesity Chronic kidney disease Diabetes Hyperthyroidism
What is atrial fibrillation?
When the atrial muscle fibres contract independently
What are features of AF on an ECG?
No P waves
Irregular QRS complexes
Why can thrombi form during AF?
Atria produces no effective systolic contraction which means it can pool and become stagnant in the atria and form a thrombus
What are symptoms of arrhythmias?
Asymptomatic Palpitations Dyspnoea Chest pain Fatigue Embolism
What investigations should be carried out for AF?
12 lead ECG for 24hrs
Blood test: esp. TFTs
Echo
What is the treatment of AF to control rate?
Digoxin
Beta blocker
CCB
All with warfarin (or aspirin with low risk)
Describe AF ECG
Jagged line representing the many small contraction of different atrial fibres, sometime signals pass through the ventricles and cause contraction, but the QRS complexes occur at irregular intervals and usually at high rates
What is are the aim for AF treatment?
Restore sinus rhythm
Rate control
Assess coagulation needs
What are the treatments for AF to restore sinus rhythm?
Ic/III drugs +/- DC cardioversion
Pace and ablation of AV node
Substrate modification eg Pulmonary vein ostial ablation,
maze procedures
What are two types supraventricular tachycardia?
AV-nodal re-entrant tachycardia
AV re-entrant tachycardia
What are the symptoms of supraventricular tachycardia?
Palpitations
Dyspnoea
What is the treatment for SVT?
No treatment (good prognosis)
AV ablation
Drugs (B blockers)