Atrial Fibrillation

Question 1

What are the types of AF?

Answer 1

Paroxysmal - Recurrent but terminates spontaneously within 7 days

Persistent - Lasts longer than 7 days and requires termination by pharmacological/electrical cardioversion

Permanent - Refractory to cardioversion, sinus rhythm cannot be maintained. AF is accepted as final rhythm

Question 2

What are some cardiac causes of AF?

Answer 2

• Hypertension
• IHD
• Valvular disease
• Cardiomyopathy

Question 3

What are some non cardiac causes of AF?

Answer 3

Respiratory conditions
Endocrine - Thyrotoxicosis, DM
Infection
Electrolyte disturbances (hypokalaemia, hypomagnesia)
Drugs - Bronchodilators, thyroxine 
Lifestyle - Alcohol and caffeine

Question 4

What is the pathophysiology of AF?

Answer 4

Atrial myocardium - Has a short action potential with a refractory period that reduces with an increasing rate, allowing rapid contraction
Two theories:
1. Multiple wavelets become fragmented
2. Many autonomic foci located primarily in the pulmonary veins
These chaotic impulses are intermittently conducted by the AVN, causing an irregular ventricular response.

Question 5

What are the symptoms of AF?

Answer 5

- Asymptomatic in lots of people
Symptoms - 
- Palpitations
- Dyspnoea
- Angina
- Presyncope

Question 6

What are the signs of AF?

Answer 6

• Irregularly irregular pulse
• Hypotension
• Tachycardia

Question 7

What investigations would you undertake?

Answer 7

Bedside -

• Observations
• Blood pressure
• ECG

Bloods -

• FBC, U+E, TFT, Cholesterol, Bone profile (Ca+), Mg
• Cardiac enzymes

Imaging -

• CXR
• CT/MRI if embolic event suspected
• Echocardiogram (LA dilatation, mitral valve)

Question 8

What would an ECG show in AF?

Answer 8

• Irregularly irregular QRS
• Absent P waves
• Wavy baseline

Question 9

How do you manage acute AF?

Answer 9

If patient systemically unwell:
- ABCDE and get senior help

If patient is stable and AF started <48hrs ago:
- Rhythm control - DC cardiovert/flecainide/amiodarone
- If this is delayed at all, start heparin
OR
- Rate control

If patient is stable and AF started >48hrs ago:

• Rate control with bisoprolol or diltiazem
• Anticoagulate for 3 weeks before giving elective rhythm control (DOAC/warfarin)

In all cases -

• Correct electrolyte imbalances
• Control any associated illnesses eg lung pathology
• Anticoagulate (heparin until risk assessment)

Question 10

What are the principles of management for chronic AF?

Answer 10

Main goals are rate control and anticoagulation, but rhythm control appropriate if:

• Symptomatic or CCF
• Presenting for the 1st time
• AF despite precipitant correction

Question 11

What anticoagulation can be offered in chronic AF?

Answer 11

DOAC or warfarin

Question 12

What two tools can be used to assess bleeding or clotting risk in a patient with AF?

Answer 12

CHA2DS2 - VASc score - Assesses need for anticoagulation

HAS-BLED - Assesses bleeding risk

Question 13

What are contraindications to flecainide?

Answer 13

• Structural heart disease

- IHD

Question 14

What rate control can be given in chronic AF?

Answer 14

1. Beta blocker or rate limiting CCB are first line
2. Add digoxin if this fails
3. Add amiodarone if this fails

Question 15

What do you not give beta blockers with?

Answer 15

VERAPAMIL !!!

Question 16

What rhythm control can be offered in chronic AF?

Answer 16

1. Elective DC cardioversion
   - Do echo first to check for thrombi
   - If risk of failure (ie done before and failed), give amiodarone for 4 wks then 12 months after
2. Flecainide
3. Amiodarone

Question 17

What is an acceptable treatment for paroxysmal AF?

Answer 17

‘Pill in a pocket’
Ie sotalol or flecainide PRN
- Still give anticoagulation
- Given if infrequent, BP still over 100, no LV dysfunction

Question 18

What is the treatment for atrial flutter

Answer 18

• Anticoagulate
• Rate and rhythm control but DC cardioversion is preferred
• Recurrence rates are high so radiofrequency ablation is recommended (of AVN) with pacing