Automatic mode switching of implantable pacemakers: I. Principles of instrumentation, clinical, and hemodynamic considerations.
Automatic mode switching (AMS) is now a programmable function in most contemporary dual chamber pacemakers. Atrial tachyarrhythmias are detected when the sensed atrial rate exceeds a "rate-cutoff," "running average," "sensor-based physiological" rate, or using "complex" detection algorithms. AMS algorithms differ in their atrial tachyarrhythmia detection method, sensitivity, and specificity and, thus, respond differently to atrial tachyarrhythmia in terms of speed to the AMS onset, rate stability of the response, and speed to resynchronize to sinus rhythm. AMS is hemodynamically beneficial, and most patients with atrial tachyarrhythmias are symptomatically better with an AMS algorithm in their pacemakers. New diagnostic capabilities of pacemaker especially stored electrograms not only allow programming of the AMS function, but enable quantification of atrial fibrillation burden that facilitate clinical management of patients with implantable devices who have concomitant atrial tachyarrhythmia.
Lau
Chu-Pak
CP
Department of Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong. cplau@hkucc.hku.hk
Leung
Sum-Kin
SK
Tse
Hung-Fat
HF
Barold
S Serge
SS
D000465:Algorithms; D001281:Atrial Fibrillation / Q000517:prevention & control; D001282:Atrial Flutter / Q000517:prevention & control; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004562:Electrocardiography; D004867:Equipment Design; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D010138:Pacemaker, Artificial