More than three types of ECG manifestations in one patient with dual atrioventricular nodal non-reentrant tachycardia (DAVNNT) are rare. We report a 51-year-old male patient with DAVNNT consisting of six types of ECG patterns leading to tachycardia-induced cardiomyopathy. After radiofrequency ablation of the slow pathway, DAVNNT was eliminated and cardiac function was restored.