Author: Dylan Luyten M.D. Educational Pearls: Ashman’s Phenomenon occurs in the setting atrial fibrillation and mimics ventricular tachycardia, but is harmless. On ECG, the pattern of Ashman Phenomenon is a long cycle, followed a short cycle, followed by a complex wide complex beat. The wide complex beats have  right BBB morphology. The long R-R followed by a short R-R leads to conduction down the left bundle branch while the right bundle branch is still in a refractory period. References: https://lifeinthefastlane.com/ecg-library/atrial-fibrillation/