Chapter 2 - Arrhythmias

Question 1

What are ECTOPIC beats?

Answer 1

Ectopic beats are ‘extra’ or premature beats which may cause someone to have palpitations.

Treatment is rarely required if patient has otherwise normal heart.

If troublesome then B-blocker may be used (safer than other suppressant drugs).

Question 2

Anti-arrhythmics can be classified into 4 classes (the Vaughan Williams Classification) based on their effects on the electrical behaviour of myocardial cells. What are these four classes?

Answer 2

Class I- membrane stabilising drugs
1A - dysopyramide
1B - lidocaine HCL
1C - flecainide acetate; propafenone HCL
Class II - Beta blockers
Class III - amiodarone; dronedarone; sotalol (also class II)
Class IV - CCBs (includes verapamil NOT dihydropyridines

*Adenosine - another anti-arrhythmic but does not fall under the above category

Question 3

What is ATRIAL FIBRILLATION?

Answer 3

AF is the most common sustained cardiac arrhythmia (NICE).

It is caused by excitement of myocardial cells in the atria (outside of the normal sinoatrial node) causing electrical impulses to be sent in a disorganised way.

Question 4

Why is it important to treat AF?

Answer 4

AF is a significant risk factor for stroke and other morbidities.

patients with AF are x5 more likely to have a cardioembolic stroke than similar patients without AF

Treatment is there to reduce symptoms and prevent complications (esp. stroke)

Question 5

We use the CHA2DS2-VASC scoring system to assess the risk of stroke. What does this acronym stand for?

Answer 5

C - congestive heart failure [1]
H - hypertension [1]
A - age >/= to 75 years old [2]
D - diabetes melllitus [1]
S - stroke/TIA/thromboembolism (previous) [2] 
V - vascular disease [1]
A - age 65-74 years old [1] 
S - sex female [1]

Question 6

Assessing bleeding risk when completing a stroke risk assessment is also important. What does HAAAS- BLED stand for?

Answer 6

H - hypertension (systolic > 160mmHg) 
A - abnormal liver function 
A - abnormal renal function 
A - alcohol (>/= 8units/week) 
S - stroke/TIA 
B - bleeding 
L - labile INR (poorly controlled)
E - elderly (>65 years old) 
D - drugs (antiplatelets or NSAIDs)

Question 7

When do we start anti-coagulation in patients with AF?

Answer 7

In patients with confirmed diagnosis of AF and in whom sinus rhythm has NOT restored with 48hours.
Patients who have a high recurrence risk of AF
Patients with a prolonged history of AF (longer than 12 months)
Patients with a history of failed cardioversion attempts
Also if stroke risk outweighs bleeding risk.

CHADS-VASc score >/= 2

Question 8

Rate control is the preferred first line drug treatment in patients with AF except in 5 cases. What are these 5 cases?

Answer 8

1) new onset AF
2) AF with a reversible cause
3) AF secondary to HF
4) atrial flutter in whom ablation strategy (procedure to ‘scar’ the heart in the places which are causing abnormal arrhythmias)
5) if rhythm control is more suitable based on clinical judgement

Question 9

Which class of drug is first line to control rate in AF?

Answer 9

Standard B-blocker (not sotalol)
Or
Rate-limiting CCB (e.g verapamil; diltiazem)

Question 10

When is digoxin effective as a treatment for rate control in AF?

Answer 10

Digoxin has shown to be effective for controlling rate at rest. Suited for a patient who leads a sedentary lifestyle.

Question 11

If monotherapy fails to control rate in AF, what is the next step in terms of pharmacological treatment?

Answer 11

Dual therapy. Combination may consist of a standard B-blocker, CCB or digoxin.

*combination of B-blocker (licensed to be used in HF) and digoxin is preferred in patients with reduced ventricular function.

Question 12

If AF is accompanied by heart failure which drug is the preferred drug of choice for rate control?

Answer 12

Digoxin

Question 13

Post cardioversion, if drug treatment is required to maintain sinus rhythm in AF, what is the first line drug or drug class of choice?

Answer 13

Standard B-blocker (not sotalol)

Question 14

Why should aspirin not be offered as monotherapy for the prevention of emboli?

Answer 14

Only MODEST benefit in comparison to risk of bleeding. Other anti-coagulants such as warfarin have been proven to be much more effective.

Question 15

What are the symptoms of AF?

Answer 15

Palpitations, dyspnoea (SOB), fatigue, chest pain

Question 16

How is AF characterised on an ECG?

Answer 16

Absence of the P wave. (P wave represents atrial contraction).

Question 17

NICE recommends adopting a rhythm control strategy for persistent AF under what conditions?

Answer 17

1) patient is symptomatic (I.e SOB, palpitations, chest pain)
2) under 65 years old
3) new onset AF
4) AF secondary to a precipitating factor
5) have congestive heart failure

Question 18

NICE recommends adopting a rate control strategy for persistent AF under what conditions?

Answer 18

1) over 65 years old
2) have coronary heart disease
3) have contraindications to antiarrythmic medicines
4) unsuitable for cardioversion

Question 19

In a patient who had an ECG and was confirmed to have AF, however there is suspicion of some form of underlying structural heart disease what would be the next best step to take?

1) perform a transthoracic echocardiogram
2) electrical cardioversion
3) pharmacological cardioversion

Answer 19

1) transthoracic echocardiogram

NICE recommends that this assessment be performed in people with AF and where there is a high risk or suspicion of underlying structural/function heart disease which will influence choice of treatment

Question 20

When should a ‘pill in the pocket’ strategy be considered?

Answer 20

1) no history of left ventricular dysfunction or valvular heart disease
2) history of infrequent symptomatic episodes of PAF
3) have a systolic BP greater than 100mmHg and a resting heart rate above 70bpm
4) able to understand how and when to take the medication

Question 21

What is Tosarde de pointes?

Answer 21

Form of ventricular tachycardia (long QT interval) - often drug induced