A 70-year-old man was admitted to the emergency department for several hours of palpitations, dizziness, and dyspnea. The patient had a history of hypertension, diabetes mellitus, dyslipidemia, chronic obstructive pulmonary disease, and paroxysmal atrial fibrillation. His medications included eprosartan, amlodipine, atorvastatin, sitagliptin, indacaterol, and acenocoumarol. On arrival, his heart rate was 170 bpm and blood pressure was 110/50 mm Hg. The following 12-lead ECG was obtained (Figure 1). Figure 1. ECG obtained at admission in the emergency department. Based on the ECG, what is the most likely diagnosis? Please turn the page to read the diagnosis. The ECG in Figure 1 shows a wide QRS complex tachycardia at 170 bpm. Wide QRS complex tachycardia can be originated by 3 main mechanisms1: 1. Ventricular tachycardia (VT). 2. Supraventricular tachycardia (SVT) …