atrial fibrillation

Question 1

what is atrial fibrillation

Answer 1

Chaotic and disorganized atrial activity produces an irregular heartbeat

Question 2

causes:

Answer 2

• Hypertension and heart failure are most common causes in the developed world
• Other causes: MI, hyperthyroidism, rheumatic heart disease, sepsis and electrolyte disturbances
• No cause found in 2-10% (idiopathic) - lone AF

Question 3

Pathophysiology

Answer 3

• Hundos💸 of re-entrant circut cause Afib
• Ectopic foci in pulmonary veins cause irregular atrial rhythm between 300-600 bmp
• AV is unable to transmit beats as quickly as this and so does so intermittently, resulting in an irregular ventricular rhythm
• Filling time is reduced which reduces CO - allows stasis of blood which increases stroke risk
  → Can cause congestive heart faliure, stiff LV

Question 4

Paroxysmal

Answer 4

≤48 hrs

Question 5

Persistent

Answer 5

≥48 hrs

Question 6

Permanent (chronic) =

Answer 6

unable to cardiovert to NSR

Question 7

symptoms

Answer 7

• Incidental finding in ~30% of patients
• Can also present w rapid palpitations, pre-syncope (dizziness), dyspnoea and/or chest pain following onset of AF

Question 8

signs

Answer 8

Irregularly irregular pulse

Question 9

investigations

Answer 9

ECG:
- Atrial rate >300 bmp
- Irregularly irregular rhythm
- No P waves - irregular baseline
- Narrow QRS
- Presents very fast, 2AV looks regular at glance “pseudo-regularisation”

Question 10

acute management

Answer 10

• Carry out emergency electrical cardioversion in patients with life-threatening haemodynamic instability caused by new-onset AF
• As long as there are no contraindications, offer heparin at initial presentation and continue until appropriate anticoagulation according to CHA2DS2-VASc started

Question 11

In people with AF presenting acutely without life-threatening haaemodynamic instability:

Answer 11

• Offer either rate or rhythm control if the onset of the arrythmia is less than 48 hours
• Offer rate control if onset is more than 48 hours or is uncertain

Question 12

All patients with AF should have rate control as 1st line unless:

Answer 12

• There is a reversible cause for their AF
• AF is of new onset
• AF is causing heart failure
• They remain symptomatic despite being effectively controlled

Question 13

Options for rate control:

Answer 13

1. β-blocker e.g. atenolol is first line
2. CCB e.g. diltiazem (not preferable in heart failure)
3. Digoxin (only in sedentary people, needs monitoring and risk of toxicity)

Question 14

AF Pathophysiology

Answer 14

Lost ‘atrial kick’ and decreased filling times (reduced diastole)&raquo_space; reduced cardiac output

Can result in congestive heart failure, especially in the presence of a stiff ventricle eg LVH

Question 15

Management

Answer 15

Rhythm control
Objective : Maintain SR

Rate control
Objective: Accept AF but control ventricular rate

Anti-coagulation essential in both treatment strategies if high risk for thromboembolism

Question 16

Restoration of NSR

Answer 16

Pharmacologic cardioversion (anti-arrhythmic drugs e.g. amiodarone)
Direct Current Cardioversion (DCCV)

Question 17

Maintenance of NSR

Answer 17

Anti-arrhythmic drugs

Catheter ablation of atrial

focus/ pulmonary veins
Surgery (Maze procedure)

Question 18

Anti-arrhythmic Drugs

Answer 18

Class 1: reducing Na channel current
Lignocaine, quinidine, flecainide, propafenone

Class II: B-Adrenergic antagonists
Propranalol

Class III: action potential prolongation
Amiodarone, sotalol
DRONEDARONE

Class IV - Ca channel antagonists
Verapamil

Question 19

honestly just try and understand notes + powerpoint

Answer 19

cue cards aint working