Ventricular Tachycardia: Electrical Alternans

Report:

Ventricular tachycardia 153/min

Sinus rhythm 86/min

Complete A-V dissociation

Comment:

This is a fairly typical VT, LBBB-like, with slurred V1 downstroke. The diagnosis is strengthened by the obvious A-V dissociation.

In lead 2 and V2-3, there is a subtle electrical alternans. It has no significance for the diagnosis of VT (although it is much more often observed, by me, at least, in SVT) nor any implication for the myocardial status at a rate as fast as this.

This trace, for some reason, had a wide range of different diagnoses by the hospital staff, even though it was originally “posted” as a fairly typical example of VT. It thus came to illustrate an important rule of hospital medicine: if something is posed as a conundrum, it becomes one!23

Below (Fig 20a) is the patient’s admission ECG, showing LVH, paced and fusion beats and different-looking VEBs; only the large P waves are the same in the VT trace.

The patient had the same VT during EPS, but it could not be induced or ablated and the study was aborted; she was sent home (not by me) on flecainide.

20a. The paced beats have a slurred V1 downstroke like the VT complexes in Fig 20. The paced ones are the only ones in electrocardiography of irrefutably ventricular origin!

Here the second pacemaker spike precedes a pseudofusion beat and the last one a true fusion beat.

21. Intubated 73 year old man transferred from a peripheral hospital in cardiogenic shock following administration of sotalol, xylocaine and verapamil for broad-complex tachycardia. He had a large basal aneurysm from an old inferior infarction but no reversible ischæmia on thallium testing. He ended up transferred to another large hospital as our Intensive Care Unit was full. Eventually he received an ICD in Sydney.