We describe a 39-year-old man with premature atrial contractions at rest, in whom tachycardia was exacerbated by exercise into long-lasting atrial tachycardia of 150 beats/min with changeable grade of AV conduction. The feeling of irregular heart beating was the only symptom of arrhythmia and was well tolerated for many years. However, the signs of tachycardia-mediated cardiomyopathy with heart failure developed over several years. Successful RF ablation of focal atrial tachycardia using the CARTO system was performed. After 5 months of follow-up the patient is free from arrhythmia with a significant improvement of the HF.