Sun31October0735PM 4

A 36-year-old man presents to the Emergency department with palpitations and pre-syncope. He is a fit and healthy long distance runner who has completed a half marathon some 24 hours earlier. He admits to having celebrated the previous evening, having drunk up to six pints of beer.

He has no past medical history of note and completed an insurance medical including echocardiography only one year earlier.

Examination reveals a BP of 120/70 mmHg, pulse is 165 (atrial fibrillation). His chest is clear.

Investigations reveal:

Hb 142 g/L (135-180)

WCC 6.8 ×109/L (4.5-10)

PLT 203 ×109/L (150-450)

Na 137 mmol/L (135-145)

K 4.0 mmol/L (3.5-5.5)

Cr 102 µmol/L (70-110)

Glucose 4.2 mmol/L -

Troponin I <0.05 (<0.05)

ECG shows fast atrial fibrillation ventricular rate 160.

Which of the following is the most appropriate intervention for managing the AF?

(Please select 1 option)

Flecainide This is the correct answer

DC cardioversion Incorrect answer selected

Bisoprolol

Digoxin

Amiodarone

Explanation

Flecainide delivered IV is highly effective in converting paroxysmal atrial fibrillation. However, the results of the CAST trial, which showed increased mortality in association with its use post-myocardial infarction, have restricted its use to patients without a history of ischaemic or structural heart disease.

It is given as a loading dose of up to 150 mg over the first 30 minutes, and then at a slower rate for the next hour, and a maintenance rate for the remainder of the first 24 hours, adding up to a cumulative dose of 600 mg. Transition to oral medication is recommended as soon as possible. It is important to remember to anticoagulate the patient using low molecular weight heparin when chemically cardioverting using this drug.

In the presence of structural or ischaemic heart disease, amiodarone IV would be the first choice option for chemical cardioversion. In head-to-head trials it is marginally less effective than flecainide with respect to attaining sinus rhythm.

Bisoprolol is recommended as oral therapy by NICE guidelines for maintenance of sinus rhythm in patients with a history of paroxysmal AF.

In this situation digoxin is a suboptimal choice because it will merely reduce ventricular rate rather than attaining sinus rhythm.

In this situation with no signs of cardiac failure and preserved BP, there is no indication to progress to DC cardioversion as an emergency procedure.

Reference:

Electronic Medicines Compendium (eMC). Tambocor 10 mg/ml Injection.

NICE. Atrial fibrillation: the management of atrial fibrillation (CG180).

Answer Statistics

1

41%

2

39%

3

13%

4

3%

5

7%

Times answered: 273