[Reversible severe cardiomyopathy caused by a slow permanent tachycardia].

Incessant narrow QRS complex tachycardias may result in severe tachycardia-induced cardiomyopathy even if the heart rate during tachycardia is only moderately elevated. The risk of ventricular deterioration is particularly increased in patients with underlying congenital heart disease. In these patients, drug treatment is often insufficient. Thus, catheter ablation of the arrhythmogenic substrate is required in the majority of patients. After successful ablation, ventricular function may recover completely.