A woman in her 60s with melanoma metastatic to the mediastinum presented with intermittent palpitations and light-headedness. On physical examination, the patient was anxious and tachycardic. A 12-lead electrocardiogram (ECG) was performed (Figure, A).
Questions: Is this wide complex tachycardia ventricular tachycardia (VT) or supraventricular tachycardia (SVT) with aberrant conduction? What features on the ECG can be used to distinguish these causes?