Ventricular Tachycardia?

Report:

Broad complex tachycardia 154/min

?Sinus or SVT with aberrant conduction and massive ST segment elevation

Right axis deviation (RAD) +140o

Right bundle branch block

Probable acute inferior infarction

Comment:

The tachycardia looks bizarre enough, but the patient had adrenaline during preceding CPR and the 12-lead ECG an hour later (not shown) looked rather similar, with less ST segment elevation and narrower terminal QRS. There were also periods of AF with rapid response at other times (Fig 94a).

Further, two countershocks ((Fig 94a)) failed to cardiovert the original tachycardia, which, instead, slowed down over an hour into what is seen in the second ECG below (Fig 94b). The ST elevation in V1 possibly denotes a right ventricular infarction, a prognostically unfavourable association90. She did surprisingly well, extubated in three days and discharged home four weeks after admission.

One could rightfully object to the above report being influenced by much hindsight. But the hindsight was already mine by the time I arrived to work and saw what happened. ST segment elevation (and depression, like in 1 and aVL) is a known mimic of broad QRS morphology56. Similar situation is shown in Case 69. On the other hand, infarctional repolarisation changes of are sometimes preserved during real VT (see Case 31).

Besides, the shock therapy was not unjustifiable: periods of AF had a ventricular rate probably in excess of what the patient needed, even in pulmonary œdema. This case is meant to show how the diagnosis may or may not be right and yet lead to appropriate treatment.

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