Answer: Never skip a beat: pacing-induced polymorphic ventricular tachycardia following inferior myocardial infarction

Answer Document

Correct Answer: 3. Remove the temporary pacing wire and observe

The rhythm strip demonstrated polymorphic ventricular tachycardia preceded by R on T phenomenon induced by the temporary pacing wire (Figure 2, blue arrow). The R on T phenomenon was first described by Smirk in 1949, who reported this phenomenon preceding cardiac arrest in patients with frequent ventricular ectopy following acute myocardial infarction.¹ In the above case, this phenomenon was caused by inappropriate ventricular pacing due to poor myocardial sensing with the pacing electrode likely placed in proximity with infarcted right ventricular tissue.² The under-sensing and inappropriate pacing can be seen before (Figure 2, green arrows) and after (Figure 2, red arrows) the onset of ventricular tachycardia.

Figure 2

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The temporary pacing wire was removed, and no subsequent ventricular tachycardia was observed. The patient was transferred to the cardiac care unit for monitoring and was discharged from the hospital 5 days later without further complications.

Conflict of interest: none declared.

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