An 81-year-old male patient with a history of ischemic heart disease (severe stenosis of the proximal LAD coronary artery, RCA, and CX artery), with mild-to-moderate LV systolic dysfunction (LVEF of 45%), ischemic stroke, COPD, diabetes mellitus, and chronic lower limb ischemia is admitted to the Cardiology Department due to an episode of palpitations with sudden onset and regular rhythm, accompanied by chest pain, dyspnea, and anxiety, that had started 30 min before arriving to the Emergency Department. His ECG recorded at admittance to the Cardiology Department is presented in Fig. 1.