Pacemakers features and algorithms

Unnecessary ventricular pacing increases the risk of atrial fibrillation and heart failure hospitalization. SafeR™ is an algorithm found in the current MicroPort dual chamber models and ensures 99.9% intrinsic conduction, significantly reducing unnecessary pacing. Safer™ reduces unnecessary right ventricular pacing in both Sinus Node Disease patients and unselected AV Block patients.

Dplus pacing mode is an automatic AV Delay hysteresis algorithm, designed to promote the spontaneous atrio-ventricular conduction. The “Acceleration” and “AVD shortening” functions can also be programmed simultaneously to better sustain the patient avoiding the sudden rate drops, for example during vaso-vagal episodes.

The goal of rate adaptive pacing is to provide an increase in heart rate via an increase in cardiac pacing in response to metabolic needs: this would include during periods of exercise, but also during disease states and emotional reactions. The dual sensor technology is a combination of an accelerometer and minute ventilation for efficient rate response to chronotropic incompetence. It has been designed to blend information from accelerometer and minute ventilation sensors for a more physiologic rate response.

Rest Rate is related to rate adaptive pacing. While rate adaptive pacing increases the pacing rate to address patient demands, the rest rate algorithm uses similar data to slow the pacing rate below the programmed basic rate. In this manner, it can reproduce circadian variations without the constraint of being set by a clock schedule. In addition, rest rate has the added benefits of potentially reducing percent pacing and therefore extending battery life, and may offer patients a more physiological pacing rate.

With the Sleep Apnea Monitoring (SAM) function, MicroPort pacemakers provide the physician with automatic screening of pacemaker patients for the risk of severe Sleep Apnea. SAM has been designed to detect, count and report abnormal breathing events during the night. These events are detected using the minute ventilation signal. This allows the calculation of respiratory disturbances over the last six months, representing sleep disordered breathing events at night.

The WARAD is designed to monitor the atrial activity in order to discriminate pathological atrial waves (Atrial Fibrillation, Atrial Flutter, Atrial Tachycardias) from sinus P waves. This atrial discriminator uses atrial prematurity to trigger mode switching. Refer also to the Fallback Mode Switch Tech Corner article for more details on the Fallback Mode Switch algorithm.

The FMS function is designed to diagnose atrial arrhythmias and manage their occurrence using the WARAD (Window of Atrial Rate Acceleration Detection): in the event of atrial arrhythmia, FMS switches from DDD(R), SafeR™(R) or Dplus(R) pacing mode to an inhibited dual- chamber pacing mode DDI(R) to avoid prolonged ventricular pacing at a high rate for the entire duration of the sustained atrial arrhythmia.

Automaticity at Implantation allows the pacemaker to automatically detect if the device is implanted. It has been designed to provide a secure functioning of the device during implantation without prior or post implantation interrogation.

Automaticity at Implantation allows the pacemaker to automatically detect if the device is implanted. It has been designed to provide a secure functioning of the device during implantation without prior or post implantation interrogation.

The Anti-PMT algorithm is intended to protect the patient from Pacemaker-Mediated Tachycardia (PMT) without reducing the atrial sensing capability of the device.

The refractory periods are time intervals starting after pacing or sensing an event in the ventricular and atrial cavities. The aim is to protect the device from multiple detections of the same contraction or post-potential detection of the spike, as well as farfield sensing or crosstalk. In MicroPort pacemakers, the absolute refractory periods are fully automatic, except one or two of them (depending on pacemaker models).

The Right Ventricular Autothreshold (RVAT) function allows automatic adjustment of the ventricular pacing amplitude, according to a threshold test performed automatically by the device at regular intervals. The aim is to maintain automatically and periodically the ventricular capture and to adapt the ventricular pulse amplitude in order to ensure safety and to save energy.

The Right Atrial Autothreshold (RAAT) function allows automatic adjustment of the atrial pacing amplitude, according to a threshold test performed automatically by the device every day. The aim is to maintain automatically and periodically the atrial capture and to adapt the atrial pulse amplitude in order to ensure safety and to save energy.