Efficacy of patient activated antitachycardia pacing therapy using the Medtronic AT500 pacemaker.

A 28-year-old female with corrected anomalous pulmonary venous drainage presented with multiple atrial arrhythmias many years later. Ablation techniques eliminated most of the arrhythmias except atrial tachycardia with 1:1 AV conduction. A dual-chamber pacemaker with antiatrial tachycardia features was implanted and was shown to be effective in arrhythmia control when the standard algorithm was overridden by an external patient activation device.