What kind of heart rhythm is this?

Abstract

A 81-year-old man with severe aortic stenosis (qualified for transcatheter aortic valve implantation), mitral insufficiency, chronic heart failure (New York Heart Association [NYHA] II), paroxysmal atrial fibrillation, diabetes mellitus type 2, hypertension, abdominal aortic aneurysm was admitted to the Clinic because of heart failure exacerbation (NYHA III/IV). In the past patient was hospitalized twice — rhythm in electrocardiogram (ECG) was described as sinus tachycardia. During next hospitalization on ECG there was atrial tachycardia with 2:1 block and regular ventricular rate 100/min. This case report demonstrates difficulty in distinguishing sinus tachycardia and atrial tachycardia.