A 71-year-old male patient with a history of ischemic cardiomyopathy with severe LV systolic dysfunction (LVEF of 22%), remote inferior myocardial infarction, triple CABG for severe coronary artery disease (occlusion of the proximal LAD, significant stenosis of the right coronary artery and of the circumflex artery), implanted with a Boston Scientific Resonate CRT-D for the primary prevention of sudden cardiac death (programmed in DDD 50–130 bpm mode), and chronic ischemia of the lower limbs is admitted to the Cardiology Department for an episode of palpitations accompanied by chest pain, dyspnea, anxiety, and lightheadedness that had occurred 20 min prior to his presentation to the hospital. His ECG recorded at admittance to the Cardiology Department is presented in Fig. 1.