Atrial tachycardia, 2:1 alternate Wenckebach periodicity, and atrial standstill.

A case of atrial tachycardia, 2:1 alternate Wenckebach periodicity and atrial standstill is reported in an 80-year-old woman who complained of exertional dyspnea and occasional syncope for two years. Two blocked P' waves appeared after each Wenckebach period suggesting type B alternating Wenckebach phenomenon (Mobitz type II 2:1 A-V block distal, and Wenckebach conduction proximal).