Ectopic atrial tachycardia (EAT) is often refractory to pharmacological suppression, and if uncontrolled, it can lead to cardiomyopathy. Although RF current catheter ablation therapy has been effective in eliminating the arrhythmia, there is limited information. particularly in adult patients with regard to the reversal of the tachycardia induced cardiomyopathy. Four adult patients, 20–56 years of age, and a 6-year-old boy, were referred with refractory EAT. Four patients had heart failure and three had depressed LV function by echocardiographic criteria. AH patients underwent electrophysiological study, and RF ablation was successful in abolishing the arrhythmogenic foci. Of these, four were located in the right atrium and one in the left atrium, and were identified by recording of the earliest atrial activation. No complications occurred. Termination of the EAT resulted in symptomatic improvement. Serial echocardiographic assessment of LV function indicated a significant reversal of the cardiomyopathy picture with reduction in chamber size and recovery in systolic function; indices of diastolic dysfunction persisted in one patient. Chronic, uncontrolled EAT can cause tachycardia induced cardiomyopathy. The picture of the cardiomyopathy resolves after elimination of the focus. RF ablation is both effective and safe, and may be considered as early therapy, particularly in patients with incessant EAT and ventricular dysfunction.