Fast and FuriousBMJ 2009; 339 doi: https://doi.org/10.1136/bmj.b2339 (Published 01 July 2009) Cite this as: BMJ 2009;339:b2339
- Justine Bhar-Amato, research fellow
- 1Heart Hospital, London W1G 8PH
A 65 year old man attended the accident and emergency department complaining of episodic palpitations associated with dizziness. He had a pulse of 250 beats/min with a regular rhythm and a blood pressure of 105/78 mm Hg. Physical examination was otherwise normal. He had a history of paroxysmal atrial fibrillation and was taking flecainide 100 mg twice a day and warfarin.
Electrocardiography was performed on admission (fig 1⇓). Subsequently, a 6 mg bolus of adenosine was administered and a continuous two lead rhythm electrocardiogram recorded (fig 2⇓).
1 What is the arrhythmia shown in this patient’s electrocardiograms?
2 What important element in this patient’s history could have precipitated his presentation?
1 Figure 1 shows a supraventricular arrhythmia that could, on the basis of the adenosine test, be either atrial flutter or a focal atrial tachycardia. The adenosine test revealed regular organised atrial activity, which is actually flutter waves occurring at a rate of approximately 250 per min. This activity constitutes atrial flutter with 1:1 conduction. There is also intermittent atrioventricular block with the adenosine, although the rapid ventricular response rate eventually resumes (as seen towards the end of fig 2B).
2 The use of flecainide—alone, without a rate limiting drug such as a β blocker or calcium channel blocker—to treat this patient’s atrial fibrillation could be responsible for his presentation. Flecainide to treat atrial fibrillation raises the risk of atrial flutter and …