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Heart Rhythm Devices Soori Sivakumaran BASc MEng MD PEng FRCPC Medical Director, Heart Rhythm Device Clinic, Mazankowksi Alberta Heart Institute Associate Clinical Professor of Medicine University of Alberta in the ER

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Devices are common In Canada 2011 5200 new ICDs, 2076 replacement ICDs MAHI/U of A Hospital 2011/2012 210 new ICDs, 71 ICD generator changes 261 new pacemakers, 73 pacemaker generator changes HRDC MAHI/U of A 1598 pacemaker patients, 1035 ICD patients 5647 patient clinic visits Chrysalis report 2011, MEDEC Alberta Health Services

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ER Device Presentations Post-operative complications Symptoms due to the device working properly Symptoms due to the device working improperly Bystander for unrelated presentations May impact care of primary presentation May suspect problem with device

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Pacemakers: Bradycardia Symptomatic bradycardia Sinus node disease AV disease advanced second degree or third degree heart block Asymptomatic high grade AV block Not PACs with block, Type 1 second degree (inc. 2:1) Syncope bifascicular block Chronotropic incompetence No reversible cause (ie. Rx, vasovagal etc) Epstein AE, DiMarco JP et al. Circulation. 2008;117:2820-2840.

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Contains a battery that provides the energy for sending electrical impulses to the heart Houses the circuitry that controls pacemaker operations Circuitry Battery The Pulse Generator: Image www.medtronic.com

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Images www.medtronic.com Transvenous Leads Have Different Fixation Mechanisms Passive fixation The tines become lodged in the trabeculae (fibrous meshwork) of the heart Active Fixation The helix (or screw) extends into the endocardial tissue Allows for lead positioning anywhere in the heart s chamber

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Pulse generator: power source or battery Leads or wires Cathode (negative electrode) Anode (positive electrode) Body tissue IPG Lead Anode Cathode Pacemaker Components Combine with Body Tissue to Form a Complete Circuit

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NBG Code I Chamber Paced II Chamber Sensed III Response to Sensing IV Programmable Functions/Rate Modulation V Antitachy Function(s) V: Ventricle T: Triggered P: Simple programmable P: Pace A: Atrium I: Inhibited M: Multi- programmable S: Shock D: Dual (A+V) D: Dual (T+I) C: Communicating D: Dual (P+S) O: None R: Rate modulating O: None S: Single (A or V) S: Single (A or V) O: None

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Automatic Implantable Cardioverter Defibrillators 24/7 cardiac monitoring and intervention Treat VT/VF Anti-tachycardia pacing (ATP) for VT Cardioversion/Defibrillation for VT/VF Treat bradyarrhythmias Full pacing functions (single, dual) Treat heart failure Biventricular pacing

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www.hrsonline.org

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Secondary Prevention Survivors of VT/VF arrest w/o reversible cause ICDs associated with a mortality reduction of 27% 1 Patients with inducible VT on EPS Syncope and ischemic heart disease Non sustained VT and ischemic heart disease Syncope and dilated cardiomyopathy Unfortunately most patients don t survive first episode 1 AVID Investigators. N Engl J Med. 1997;337:1576-1583

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Consider Primary Prophylaxis AICD EF less than or equal 35% Ischemic cardiomyopathy (CCS Class 1) more than 4 weeks post most recent MI more than 3 months post revascularization Dilated cardiomyopathy with Class II, III heart failure (CCS Class II a) more than nine months after diagnosis Benefit modest with ARR approximately 2%/year Other high risk conditions eg. Long QT, ARVC etc.

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Discrimination: SVT vs VT Heart Rate A-V relationship Onset Stability Morphology

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Morphology Analysis

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Re-Entry Murgatroyd, Krahn et al. Handbook of Cardiac Electrophysiology. 2002.

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Anti-Tachycardia Pacing Murgatroyd, Krahn et al. Handbook of Cardiac Electrophysiology. 2002. Pain free way of terminating VT Burst pacing faster than the VT rate More effective on slower VTs Can accelerate VT

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Cardiac Resychronization Therapy Hare, NEJM 2002;346:1902-5 right ventricle right atrium coronary sinus

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Magnets and Devices Pacemakers Device paces at its predefined magnet rate Asynchronous mode (DOO, VOO) ICDs Disables tachycardia detection Does NOT affect pacing therapies

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Pacemaker Presentations Failing to capture Pacing spikes no capture Failing to sense Pacing occurs where it shouldnt like on T wave Failing to output Oversensing no pacing spikes because the device sees a signals it thinks are coming from heart beats but they are not!

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Pacing - Tachyardia Failure to mode switch tracking of atrial fibrillation/flutter with rapid paced ventricular rate Medications wont control the rate Pacemaker Mediated Tachycardia Retrograde conduction to the atrium from a PVC starts a rapid pacing cycle via the pacemaker

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Hysteresis

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The DAVID Study Adverse Effects of RV Pacing Objective To compare the efficacy of dual chamber pacing with back-up VVI pacing in patients with a standard ICD indication 506 patients randomized to DDDR pacing at 70 bpm vs VVI back-up pacing at 40 bpm No indication for bradycardia pacing Maximal tolerated medical therapy JAMA. 2002;288(24):3115-3123

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Outcome: DAVID Trial The DAVID Trial Investigators, JAMA 2002;288:3115-3123.

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MVP Basic Operation DDD(R) Switch Ventricular support if loss of A-V conduction is persistent Image www.medtronic.com

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Complex Pacing Algorithms Minimize RV Pacing Mode switching algorithms AV delay extension algorithms Prevention of atrial fibrillation Atrial overdrive / PAC suppression Rate smoothing in persistent atrial fibrillation Pacing in ventricle may result in a slower average ventricular rate

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Patient Shocks Normal function of the AICD Patient feels well post shock(s) Leave message with AICD Clinic Scheduled assessment within few days Patient feels unwell post shock(s) Go to nearest ER Patient with an device/lead under a manufacturers advisory may require urgent assessment also

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Inappropriate Shocks Shocks received for reasons other than VT/VF Causes include: Sinus tachycardia Atrial fibrillation with a rapid ventricular response Other supraventricular tachyarrhythmias Lead Fracture External noise

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Complications Lead dislodgement 2.3% Early ICD system infection 1.9% Pneumothorax 0.6% Device malfunction 0.5% Serious bleeding 0.4% Venous thrombosis 0.2% Cardiac perforation 0.1% CCS/CHRS Position Paper on Implantable Cardioverter Defibrillator (ICD) Use in Canada

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Post-op Site Check

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Hematoma

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Post AICD Implant 12 months

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` Parsonnet V, Trivedi A. Circulation. 2000;102:1192.

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Lead Infection Clinical symptoms suggestive of systemic infection and positive blood cultures warrant further evaluation with TEE Strands and clot on leads can be a normal finding Sometimes appearance can be highly suggestive of infection

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Leads Attached to Veins by Fibrotic Tissue

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Preventing Infections ECG Electrode on device site can cause erosion Starting heparin or low molecular weight heparin will cause a large hematoma Central lines provide a route for sepsis and lead infection Sepsis from any source can settle on the device leads

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Peri-Operative Device Management Device type and indication Pacemaker dependence Surgery location Accessibility to device site during procedure Canadian Cardiovascular Society/Canadian Anesthesiologists/Canadian Heart Rhythm Society Joint Position Statement on the Perioperative Management of Patients with Implanted Pacemakers, Defibrillators and Neurostimulating Devices. CJC 28(2012) 141-151.

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Reason for a device check Patient symptoms Shocks Syncope/Significant presyncope Palpitations Also consider: SOBOE: chronotropic incompetence, loss of BiV pacing Documented device failure (on ECG) Patient lost to device follow-up

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Remember Settings/notes available from Device Clinic Presence of patient in hospital is not an indication to check the device Were here to help

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Conclusion

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Heart Rhythm Device Clinic Pacemaker Clinic Nurse run, physician supervised 4 weeks, 3 months, 6 months, 12 months Assess patient symptoms Lead performance Battery Status Programming changes ICD Clinics EP Physician attended Anti-arrhythmic medications checked Episodes recorded by the device reviewed

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CRT requires wide complex ECG and Class II+ CHF