Atrial fibrillation + arrhythmias Flashcards
Pathophysiology of AF
Impaired electrical heart activity causing an irregularly irregular rhythm
Risk factors for AF
- hypertension
- Coronary heart disease
- mitral stenosis
- pericarditis
- pneumonia
- Hyperthyroidism
Presentation
Symptoms:
- palpitations
- dizziness
- syncope
- dyspnoea
Signs:
- tachycardia
- irregularly irregular pulse
Investigations
- cardiac examinations
- basic obs
- ECG
- Bloods - FBC, U+Es, TFTs, Trop I
- CXR - for underlying cause such as pneumonia
ECG changes
- absent P waves
- wavy baseline
- irregular QRS complexes
- irregularly irregular tachycardia
Management rhythm control
- if haemodynamically unstable - DC cardioversion
- if haemodynamically stable - check time of onset
Within 48 hrs:
- DC cardioversion
- or chemical cardioversion
Longer than 48hrs:
- anticoagulation with warfarin
- for 3 - 4 weeks
- cardioversion after
- or TOE to rule out clots
Chemical cardioversion
Flecainide - contraindicated in IHD
Amiodarone - 1st line in AF with HF
Rate control
- diltiazem CCB
- beta blocker
- digoxin
If one drug does not help, can use a combination of 2
CHADSVAS score management
Stroke risk stratification:
- low risk - 0 in males and 1 in females - no treatment
- medium - 1 in males and 2 in females - consider treatment
- high risk - 2+ in males and 3+ in females - warfarin
CHADSVASC scoring
Congestive HF - 1 HTN - 1 Age 75+ - 2 DM - 1 Stroke/TIA - 2 Vascular disease - 1 Age - 65 - 74 - 1 Sex = Female - 1
Max score = 9
SVT
Problem with SAN, AVN or atrium
High HR
Anomaly with P waves or PR interval
Normal QRS
Narrow complex tachycardia - SVT
VT
Problem with ventricles, Bundle of His or Perkinje fibres
High HR due to ventricle pathology
Normal P waves
Broad QRS
Broad complex tachycardia - VT
Indication for electrical DC cardioversion
Persistent AF for more than 48 hours
Haemodynamically unstable
Commonest causes of AF
IHD
Hyperthyroidism
Hypertension
Wolff Parkinson White syndrome cause, ECG changes and symptoms
Accessory pathway causing inappropriate pathway of conduction
- palpitations
- delta wave and short PR interval on ECG
Atrial flutter pathophysiology
APs continually travelling around right atrium dependent on tissue from IVC and tricuspid valve
Atrial flutter signs on ECG
2:1 P wave: QRS
Saw tooth appearance
LBBB
Broad QRS - more than 3 small squares
Negative QRS complex in leads V1 - V4
Positive QRS in V6
Left axis deviation
RBBB
Broad QRS - more than 3 small squares
V1 has bunny ear positive QRS appearance
Slurred S wave in V6
How to calculate HR from ECG
Regular: 300/squares between R-R
Irregular: how many QRS complexes in 30 squares x 10
Long term Pharmacological treatment of permanent AF
- DOAC - apixaban
- Rate control - beta blocker
- Rhythm control
If failed - ablation
Respiratory causes of AF
Chest infection
Lung cancer
Systemic causes of AF
Excessive alcohol
Hyperthyroidism
DM
Management of paroxysmal AF
Self limiting
Pill in pocket - sotalol or flecainide
Anticoag - CHADVASC
Type of AF
Paroxysmal - terminates spontaneously within 7 days
Persistent AF - lasts more than 7 days but terminates
Permanent - long term continuous AF, sinus rhythms not achievable
Why is anticoagulant given for 3 weeks before rythmn control drugs
Rhythms control drugs may mask clots
When to give rhythm control first line in Persistent AF management
young < 65 yo
Symptomatic
Presenting first time
Secondary to already treated precipitant
Atrial flutter mx
Manage as for AF
• Amiodarone to restore sinus
• Amiodarone or sotalol to maintain it
Contraindications for beta blockers
Asthma
Catheter ablation
- Anticoagulate 4 weeks before procedure
- Percutaneous procedure via groin
- Still require anti coagulation lifelong after
Complications of catheter ablation
Cardiac tamponade
Stroke
Pulmonary valve stenosis
If CHADVAS = 0 - 1
Ensure a transthoracic echocardiogram has been done to exclude valvular heart disease
SVT management
- Vagal manoeuvre- vasalva or carotid sinus massage
- IV adenosine
- if asthmatic give verapamil - Electric cardio version
Broad complex tachycardia
Regular - amiodarone
Irregular - refer to cardiologist
