Abstract
A middle-aged man with no previous cardiac history was admitted to the hospital being treated for thigh cellulitis, during his stay he developed palpitations and tachycardia which on initial ECG showed atrial flutter with a 2:1 AV block and evidence of an accessory pathway. He was subsequently given AV nodal blocking agents in the form of beta-blockers (bisoprolol) to slow his heart rate down; unfortunately, this led to hemodynamic instability due to 1:1 conduction of the atrial flutter down the accessory pathway. This case report demonstrates the importance of recognising pre-excitation on an ECG and the potential adverse effect of administering AV nodal blockade.