We describe the case of a 50-year-old woman with the clinical diagnosis of cardiomyopathy associated with supraventricular tachycardia refractory to pharmacological treatment. The totally irregular tachyarrhythmia was the result of different episodes of atrial tachycardia, atrial flutter and atrial fibrillation that could be identified in the surface ECG. These findings and the patient's symptoms were all caused by a single focal tachycardia originating from the left upper pulmonary vein. Ablation of this focus represented a curative antiarrhythmic therapy also restoring a normalized ventricular function. Thus, an ablation of the AV node with consecutive pacemaker implantation could be prevented.