Sensing g Assurrance O Overview Sensing Assurance allows s for automattic adjustmen nts to program mmed sensittivity in pacing devices, aiding in ppropriate se ensing during g AF and pre eventing overrsensing due to large T w waves. It allow ws for the automatic ap ad djustment of atrial and ve entricular sen nsitivity levels s in IPGs by monitoring P P- and R-wavve values. P Programming Sensing Assurance will ad djust sensitivity only if the programmed d mode allow ws both senssing and pacing in a hamber, with h the exceptio ons that adjustments are allowed in th he VDD, AAI< <=>DDD, an nd AAIR<=>D DDDR ch m modes, and are not allowe ed in the AAT T/VVT modes s. It is nomina ally On. To program th his feature, go to Params -> Atrial / Ve entricular Sen nsitivity. C Considerations:  While Sensing Ass surance is On n, there are limits to man ually program mming sensitivity values (refere ence table be elow).  Ventric cular Safety Pacing (VSP P) must be prrogrammed O On for ventriccular Sensing g Assurance e operattion. F Feature Ope eration The following steps describe how Sens sing Assuran nce operates.. Step 1: Devic ce calculates s Target Sen nsing Margin Each nonrefractory sensed ev vent (AS or VS) V is measu red and com mpared to the Target Senssing Margin, which varries dependin ng on the sen nsitivity settin ng, the type o of lead (A an nd V) and its polarity. See table t on the next n page: © 2013 Medtron nic, Inc. ww w.medtronic cfeatures.co om Page 1 of 4 Chamber and Sensing Polarity Target Sensing Margin Atrial Bipolar 4.0 - 5.6 x (programmed value) Atrial & Ventricular Unipolar or Ventricular Bipolar 2.8 - 4.0 x (programmed value) Example: A bipolar atrial lead set to 0.5 mV yields a target Atrial Sensing margin = 2.0 mV to 2.8 mV (4 x 0.5 mV to 5.6 x 0.5 mV). Step 2: Classification of each P wave The sensed P wave is then classified as either a low, adequate, or high amplitude. Step 3: Reprogramming sensitivity If 17 consecutive beats are “Low,” the sensitivity is adjusted to the next programmable value that is more sensitive. If 36 consecutive beats are “High,” the sensitivity is adjusted to the next less sensitive value. Sensing Assurance will not adjust Sensitivity during temporary operation. While Sensing Assurance is designed to adapt sensitivity margins in response to changes in sensed event amplitudes, Sensing Assurance may not eliminate all sources of oversensing. © 2013 Medtronic, Inc. www.medtronicfeatures.com Page 2 of 4 Example Sensing Assurance Off: When P wave amplitudes decrease during atrial flutter, the smaller P waves could be undersensed (as shown in the ECG to the right). Sensing Assurance On: When P wave amplitude decreases during atrial flutter, sensing assurance will readjust the sensitivity level to sense smaller P waves. Performance Data The following clinical data supports the need for an automatic sensing feature:  Changes in P and R wave signal amplitudes may occur with lead maturation, myocardial infarction, antiarrhythmia medications, atrial arrhythmias, and exercise.1  Atrial arrhythmias and exercise have been shown to affect signal amplitudes.2  Programming the sensitivity threshold and safety margin using the sinus rhythm signal amplitude may not be adequate to sense the atrial events during the atrial arrhythmias.3 Devices Pacemakers Adapta® DR, Adapta SR, Versa® DR, Sensia® DR, Sensia SR References 1. Castro A, Liebold A, Vincente J, Dungan T, Allen JC Jr. Evaluation of autosensing as an automatic means of maintaining a 2:1 sensing safety margin in an implanted pacemaker. Autosensing Investigation Team. PACE. November 1996;19(11, Part II):1708-1713. 2. Frohlig G, Schwerdt H, Schieffer H, Bette L. Atrial signal variations and pacemaker malsensing during exercise: a study in the time and frequency domain. J Am Coll Cardiol. April 1988;11(4):806-813. 3. Wood MA, Moskovljevic P, Stambler BS, Ellenbogen KA. Comparison of bipolar atrial electrogram amplitude in sinus rhythm, atrial fibrillation, and atrial flutter. PACE. February 1996;19(2):150-156. ® ® ® Source: Medtronic Adapta /Versa /Sensia Reference Guide. This document is provided for general educational purposes only and should not be considered the exclusive source for this type of information. At all times, it is the professional responsibility of the practitioner to exercise independent clinical judgment in a particular situation. Changes in a patient’s disease and/or medications may alter the efficacy of a device’s programmed parameters or related features and results may vary. The device functionality and programming described in this document are based on Medtronic products and can be referenced in the published device manuals. © 2013 Medtronic, Inc. www.medtronicfeatures.com Page 3 of 4 Indications, Safety, and Warnings Brief Statement: IPGs Indications Implantable pulse generators (IPGs) are indicated for rate adaptive pacing in patients who may benefit from increased pacing rates concurrent with increases in activity and increases in activity and/or minute ventilation. Pacemakers are also indicated for dual chamber and atrial tracking modes in patients who may benefit from maintenance of AV synchrony. Dual chamber modes are specifically indicated for treatment of conduction disorders that require restoration of both rate and AV synchrony, which include various degrees of AV block to maintain the atrial contribution to cardiac output and VVI intolerance (e.g. pacemaker syndrome) in the presence of persistent sinus rhythm. For the MR Conditional IPG, a complete pacing system consisting of an RVDR01 IPG and 2 SureScan leads is required for use in the MR environment. Contraindications IPGs are contraindicated for dual chamber atrial pacing in patients with chronic refractory atrial tachyarrhythmias; asynchronous pacing in the presence (or likelihood) of competitive paced and intrinsic rhythms; unipolar pacing for patients with an implanted cardioverter defibrillator because it may cause unwanted delivery or inhibition of ICD therapy; and certain IPGs are contraindicated for use with epicardial leads and with abdominal implantation. Warnings/Precautions Changes in a patient’s disease and/or medications may alter the efficacy of the device’s programmed parameters. Patients should avoid sources of magnetic and electromagnetic radiation to avoid possible underdetection, inappropriate sensing and/or therapy delivery, tissue damage, induction of an arrhythmia, device electrical reset or device damage. Do not place transthoracic defibrillation paddles directly over the device. Potential Complications Potential complications include, but are not limited to, rejection phenomena, erosion through the skin, muscle or nerve stimulation, oversensing, failure to detect and/or terminate arrhythmia episodes, and surgical complications such as hematoma, infection, inflammation, and thrombosis. See the device manual for detailed information regarding the implant procedure, indications, contraindications, warnings, precautions, and potential complications/adverse events. For further information, please call Medtronic at 1-800-328-2518 and/or consult Medtronic’s website at www.medtronic.com. Caution: Federal law (USA) restricts these devices to sale by or on the order of a physician. World Headquarters Medtronic, Inc. 710 Medtronic Parkway Minneapolis, MN 55432-5604 USA © 2013 Medtronic, Inc. Tel: (763) 514-4000 Fax: (763) 514-4879 Toll-free: 1 (800) 328-2518 (24-hour technical support for physicians and medical professionals) www.medtronicfeatures.com Page 4 of 4