While tempting to assume that the lateral leads are secondary to artefacts – for example a loose lead, tremor, etc – the normal rhythm strip and the pattern makes it unlikely.

This patient has had a heterotopic transplant and has presented with one of his hearts in VT and the other in a sinus rhythm. Before the advent of ventricular assist devices (or VA ECMO) heterotopic cardiac transplantation was performed when the donor heart did provide sufficient cardiac function on its own. In this procedure the patient’s own heart is remians in situ and the new heart is positioned so that the chambers and blood vessels of both hearts are connected to form what is effectively a “double heart.” In particular, it may be performed in patients with refractory pulmonary hypertension. For these patients, orthotopic transplantation without a VAD or other assistance is at high risk of the donor heart failing due to elevated right heart pressures. Heterotopic transplantation may also be used when there is a significant mismatch between the patient size and heart size. In this case if the donor heart is too small then the recipient heart may take on the “assist device” role, and so help supporting the circulation during the initial adaptation.

Of course an alternative explanation for this ECG is that there is a Gallifreyan in your resus bay!