Flecainide: From AF to Ventricular Tachycardia

Report:

Atrial fibrillation with rapid ventricular response

Ventricular tachycardia 214/min

Respiratory artefact

Comment:

This is one of the best examples of proarrhythmia I have ever seen. There is something ironic in the meticulous recording of the increments of flecainide, leading to a nasty surprise at the end (when the 150 mg ampoule was all in).

The initial run of VT was not sustained: a VEB terminated it at near the end of the strip. Note that the two supraventricular beats seen there show no intention of slowing down, despite the flecainide. The respiratory artefact is less prominent than in the bottom strip and is best observed looking at the T waves.

At first, the bottom strip looks polymorphous; then one sees it’s only dimorphic; finally one realises that the phasic change in QRS shape is due to the patient’s tachypnœa. The strips below, (Fig 73a) taken after transfer to Woden Valley Hospital, show the respiratory cycles even better. Positive pressure ventilation abolished this artefact soon afterwards (it usually does).

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