Supraventricular Tachycardias - Atrial Fibrillation

Question 1

Types of tachycardic arrythmias

Answer 1

A.fib
Atrial flutter
AVRT (Wolff-Parkinson White Syndrome)
V.fib
V.tach + Long QT

Question 2

Definition

Answer 2

Irregularly irregular atrial firing rhythm at 300-600bpm. MOST COMMON Cardiac arrythmia

Question 3

Epidemiology

Answer 3

60+
FEMALE
Diabetes
High BP
Coronary Artery Disease
Post MI
Structural heart disease

Question 4

Aetiology (just think H)

Answer 4

HEART FAILURE
Hypertension,
Hyperthyroidism
Hypokalaemia
Hypomagnesemia
IHD
Mitral stenosis
Pneumonia

Question 5

Risk Factors

Answer 5

60+
T2DM
HTN
Valve stenosis (Mitral stenosis)
Hx of MI
Hyperthyroidism
Smoking
Excessive caffeine or alcohol consumption
Stress
Medication - salbutamol, atropine, decongestants (e.g. pseudoephedrine)
Recreational drug use: cocaine, and metenephrines

Question 6

Pathophysiology

Answer 6

Rapid re-entrant ectopic foci (300-600 bpm firing rate) cause ARIAL SPASM - not coordinating contraction like the typical physiology pathway. Causes atrial blood to pool instead pump efficiently to ventricles. therefore, decrease in CO and increase risk of thromboembolic events.

Question 7

Signs

Answer 7

Irregularly irregular pulse
Apical pulse greater than the radial rate
1st heart sound of variable intensity
Thromboembolic (ischaemic stroke)

Question 8

Symptoms

Answer 8

May be asymptomatic
May cause:
Chest pain
Palpitations
Dyspnoea
Faintness (syncope)
Hypotensive

Question 9

Types of A.fib

Answer 9

Paroxysmal (episodic)
Persistent (longer than 7 days)
Permanent (sinus rhythm unrestorable)

Question 10

Diagnosis

Answer 10

GOLD STANDARD: ECG - irregularly irregular pulse with narrow QRS (<120ms) + no p waves (fibrillatory squiggles)

Question 11

Treatment

Answer 11

Acute < 48 hours + unstable (syncope, shock, chest pain, HF) - ABCDE -> DC cardioversion + amiodarone if unsuccessful
Chronic = (RATE CONTROL) Beta blocker (Bisoprolol) or CCB (Verapamil) = 1st line
If fails add digoxin = 2nd line (only given as monotherapy in sedentary patients)
DONT give BB with CCB as risk of bradycardia + heart block
Third line = Add amiodarone
OR
(RHYTHM CONTROL) Surgical radiofrequency ablation = Elective DC cardioversion + warfarin to restore PQRST shape
(Both prevent further episodes)

Question 12

Complications

Answer 12

Heart failure
Ischaemic stroke
Mesenteric ischaemia

Question 13

What is the atrial fibrillation stroke risk scoring system used?

Answer 13

CHA2DS2-VASc score:
Factors: congestive HF, HTN, Age 75 +, DM, Stroke, Vascular disease, Ages 65-74, Sex (FEMALE), 2< = Oral coags needed

Question 14

HAS-BLED score

Answer 14

Assessment of risk of major risk in AF patients on anticoag
> (or same as 3 (max 9) = regular reviews!