A case of Romano-Ward syndrome effectively treated by both propranolol and atrial pacing is reported. A 33 year-old female, who had experienced syncopal episodes since she was 20 years old, had a family history showing her son with QTc 0.46. Her QT-U interval and QTc were both 0.6 second when propranolol was not administered. It shortened to 0.28 second and 0.39 respectively under exercise stress testing, and also shortened to 0.41 second and 0.43 respectively when left satellite ganglion block was used. Electrophysiologic study demonstrated that both sinus and atrioventricular nodal functions were normal, but the refractory periods of right and left ventricle differed significantly, and nonsustained ventricular tachycardia was induced. Her QT-U and QTc intervals shortened to 0.37 seconds and 0.43 respectively through both the treatment of 80 bpm atrial pacing, and the administration of 80mg propranolol. She has never experienced a syncopal episode.