title: How to test mode switching in pacemakers implanted in patients: the MOST study.
abstract: Optimal management of atrial arrhythmias with dual chamber pacemakers requires proper performance of automatic mode switching (AMS). The aim of this study was to develop a reliable technique to test the AMS function by using an external electronic device capable of mimicking the occurrence of supraventricular arrhythmias (Supraventricular Arrhythmia Simulator [SAS]). The SAS delivers low voltage pulse trains (200 mV, 20 ms) through two skin electrodes. Each pulse train lasts 15 seconds and starts synchronously with a pacing pulse of the implanted pacemaker to avoid interference from the operator. The pulse train rate is set at 350, 250, and 160 beats/min to simulate AF, atrial flutter, and atrial tachycardia (AT), respectively. Thirty-five patients implanted with Vitatron pacemakers, whose AMS system has been previously validated, were enrolled. Atrial and ventricular sensing were programmed in unipolar mode at 0.5 mV and in bipolar mode at > 2 mV, respectively. All pulses from the SAS were detected by the atrial channel at an amplitude ranging from 1 to 3 mV. The test proved to be safe and reliable at rest and during exercise. AMS occurred immediately at onset or at offset of atrial arrhythmias, and no adverse interference on pacemaker function was seen from the SAS. In conclusion, the described technique and the SAS are safe and reliable for patient and pacemaker function and can be proposed as a useful method to verify proper performance of AMS function irrespective of the type of implanted devices.
authors.affiliation: Istituto Clinica Medica e Cardiologica, Firenze, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Padeletti
authors.forename: Maurizio
authors.initials: M
authors.lastname: Gasparini
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Porciani
authors.forename: Paolo
authors.initials: P
authors.lastname: Pieragnoli
authors.forename: Andrea
authors.initials: A
authors.lastname: Colella
authors.forename: Antonio
authors.initials: A
authors.lastname: Michelucci
authors.forename: Alessandro
authors.initials: A
authors.lastname: Proclemer
authors.forename: Stefano
authors.initials: S
authors.lastname: Tognarini
authors.forename: Massimo
authors.initials: M
authors.lastname: Mantica
authors.forename: Fernando
authors.initials: F
authors.lastname: Coltorti
authors.forename: Giorgio
authors.initials: G
authors.lastname: Corbucci
authors.forename: Richard
authors.initials: R
authors.lastname: Sutton
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000628:therapy; D004562:Electrocardiography; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D013617:Tachycardia, Supraventricular / Q000628:therapy; D013686:Telemetry