A 68-year-old man presents with a syndrome of alcohol withdrawal. ECG Shows?

Ans. (a) Atrial flutter.* This ECG reveals a regular narrow complex tachycardia at a rate of 150 beats/min. Coarse sawtooth waves are seen best in the inferior leads diagnostic of atrial flutter with 2 to 1 AV conduction.* Whenever a supraventricular tachycardia at a rate of close to 150 beats/ min is present, the diagnosis of atrial flutter should be considered. The QRS axis is normal, and there is no clear evidence of ischemia.* Typical atrial flutter is caused by a macro-reentrant circuit in the right atrium, involving the tricuspid annulus. Structural heart disease, intrinsic lung disease, and states of increased sympathetic tone can all predispose to this arrhythmia.