Failure of atrial flutter detection by a pacemaker with a dedicated atrial flutter detection algorithm.

Detection of atrial flutter may be difficult for pacemakers with automatic mode switching algorithms. The Medtronic Kappa 700 device pacemakerfamily offers a dedicated Blanked Flutter Search algorithm specifically designed for the detection of atrial flutter. This report describes how spontaneous atrioventricular conduction, resulting in a sensed QRS complex at a critical time, inhibited the function of the Blanked Flutter Search algorithm to sense "concealed" or "blanked" atrialflutter. This observation underscores the need for further refinement of pacemaker algorithms for the detection of atrial tachyarrhythmias.