Atrial Fibrillation (AF)

An active 76-year-old-man developed palpitations that lasted a few minutes and settled spontaneously. He had no chest pain or other symptoms. O/E: regular pulse of 68 beats per minute, normal heart sounds, BP of 140/84. FBC, renal function and electrolytes, thyroid function, and blood glucose are normal. Although his resting ECG was normal, an ambulatory monitor confirmed two short bursts of AF recorded over a 48-hour period. Which SINGLE medication, if any, should be prescribed?

1. Apixaban

2. Dipyridamole

3. Clopidogrel

4. Aspirin

5. No medication indicated

This patient's CHA2DS2-VASc score of 3 indicates that he should be recommended oral anticoagulation to reduce his risk of stroke. Although he has paroxysmal AF, his risk is similar to having continuous AF. Anticoagulation may be with apixaban, dabigatran etexilate, rivaroxaban or a vitamin K antagonist. Antiplatelet agents are not recommended in the primary prevention of stroke.

• Patients with AF who have a CHADS2 or CHA2 DS2 -VASc score of ≥ 1 should be considered for warfarin at a target INR of 2.5 (range 2.0-3.0) - unless CHA2DS2-VASc score of 1 solely attributable to being female.

References

• Atrial fibrillation: management (NICE CG 180, 2014)

• Atrial fibrillation (CKS) / Atrial fibrillation (NHS Choices)

• CHADS-VASc score (MD+Calc)/ CHA2 DS2 -VASc/HAS-BLED/EHRA, (Chadsvasc.org): stroke risk for patients with AF

• HAS-BLED score (risk of major bleeding with anticoagulation for AF). Includes: hypertension, renal/liver disease, stroke history, prior bleeding, labile INR, age>65, medication (aspirin, clopidogrel, NSAIDs), alcohol use

• SPARC tool (Stroke Prevention in AF Risk Tool - risk of stroke and benefits of antithrombotic therapy in chronic AF)

Brugada syndrome

• Brugada syndrome (NHS Choices)

Heart block

First degree

Second degree

Third-degree/complete:

• Complete failure of conduction through the atrio-ventricular node (AVN). Continuing ventricular activity depends upon the emergence of an escape rhythm. If the block is in the AVN then the escape rhythm usually originates in the bundle of His and is fast enough to prevent symptoms. If, however, there is bundle damage, the escape rhythm is generated lower down the conducting system resulting in a slow and unreliable heart beat and life-threatening asystoles.

• ECG: regular atrial contractions (p-waves) can be seen continuing completely independently from the ventricular contractions (QRS complexes).

• Definitive treatment, once reversible causes such as drugs or electrolyte imbalance have been excluded, is with a permanent pacemaker.

• Heart block (NHS Choices)

Long QT syndrome

• Long QT syndrome (NHS Choices)

Postural tachycardia syndrome

• Postural tachycardia syndrome (NHS Choices)

Supraventricular tachycardia (SVT)

• Supraventricular tachycardia (SVT) (NHS Choices)

Wolff-Parkison-White (WPW) syndrome

• Wolff-Parkinson-White syndrome (NHS Choices)

Ventricular tachycardia/fibrillation

• This appearance could either be associated with torsades de pointes or (less commonly) with polymorphic ventricular tachycardia, which has the same appearance during the arrhythmia. In sinus rhythm however torsades de pointes has a long QT interval.

• If sustained, polymorphic ventricular tachycardia often leads to haemodynamic collapse.  It can occur in acute myocardial infarction and may deteriorate into ventricular fibrillation.

• In either case the cardiac axis rotates over a sequence of 5–20 beats, changing from one direction to another and back again. The electrocardiographic wave form (QRS) amplitude varies similarly, such that the complexes appear to twist around the baseline.

• Polymorphic ventricular tachycardiamust be differentiated from atrial fibrillation with pre-excitation, as both have the appearance of an irregular broad complex tachycardia with variable QRS morphology.

Ventricular bigeminy

Extrasystoles occur when there is electrical discharge from somewhere in the heart other than the sino-atrial node. They are classified as atrial or ventricular according to their site of origin. In this case the extrasystoles are of ventricular origin as the QRS is abnormal in shape and widened (> 120 ms). There is a compensatory pause for the heart to repolarise after the additional beat. Extrasystoles occurring at every second beat are termed bigeminy.

In the absence of heart disease, ventricular bigeminy is usually benign and the prognosis is good. Reassurance may be all that is needed. Avoidance of alcohol and caffeine and treatment with a beta-blocker such as bisoprolol may alleviate symptoms.

Consider referral for specialist advice if there is a past history of cardiac disease, 24 hour monitoring reveals very frequent extrasystoles over a 24 hour period, other symptoms such as breathlessness or dizziness are associated with palpitations, there is any exertional syncope, there is any family history of early cardiac disease or sudden death or reassurance/treatment with simple measures is not satisfactory.

References

• Da Costa D, Brady W, Edhouse J. Bradycardias and atrioventricular conduction block. BMJ 2002; 324: 535. 

• Williams H, Williams T, Dawkins S et al. Bradycardia and pacemakers. InnovAiT 2012; 5(4): 210–218.