Inappropriate sinus tachycardia is characterized by an unexplained increase of the resting sinus rate (> 100 bpm) with excess increase in response to moderate activity (mean heart rate > 90 bpm/24 h). Affected patients may suffer from heart race, palpitations, fatigue, weakness and dizziness. The mechanisms underlying inappropriate sinus tachycardia and its long term prognosis are poorly understood. Thus, diagnosis and treatment are empiric and require the initial exclusion of potential causes of secondary sinus tachycardia. Therapeutic approaches include physical training, beta blockers or ivabradine. Radiofrequency catheter ablation should be restricted to patients with refractory and longstanding symptoms.