An 84-year-old male patient with a history of ischemic heart disease treated with triple CABG at the age of 64 years (2004), arterial hypertension, persistent atrial fibrillation, dyslipidemia, and chronic renal failure is admitted to the Cardiology Department for an episode of decompensated heart failure (dyspnea on exertion, nocturnal paroxysmal dyspnea, and peripheral edema) that had progressively worsened over the previous 2 weeks prior to his presentation to the hospital. His ECG recorded at admittance to the Cardiology Department is presented in Fig. 1.