Heart Rhythm Devices in the ER 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

Devices are common In Canada 2011 MAHI/U of A Hospital 2011/2012 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

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

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.

The Pulse Generator: Contains a battery that provides the energy for sending electrical impulses to the heart Houses the circuitry that controls pacemaker operations Circuitry Lithium-iodine is the most commonly used power source for today’s pacemakers. Microprocessors (both ROM and RAM) control sensing, output, telemetry, and diagnostic circuits. Battery Image 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 Images www.medtronic.com

Pacemaker Components Combine with Body Tissue to Form a Complete Circuit Pulse generator: power source or battery Leads or wires Cathode (negative electrode) Anode (positive electrode) Body tissue Lead IPG In a bipolar system, body tissue is part of the circuit only in the sense that it affects impedance (at the electrode-tissue interface). In a unipolar system, contact with body tissue is essential to ground the IPG and allow pacing to occur. Anode Cathode

NBG Code P: Simple programmable V: Ventricle V: Ventricle T: Triggered Chamber Paced II Sensed III Response to Sensing IV Programmable Functions/Rate Modulation V Antitachy Function(s) P: Simple programmable V: Ventricle V: Ventricle T: Triggered P: Pace M: Multi- programmable A: Atrium A: Atrium I: Inhibited S: Shock D: Dual (A+V) D: Dual (A+V) D: Dual (T+I) C: Communicating D: Dual (P+S) The first letter refers to the chamber(s) being paced The second letter refers to the chamber(s) being sensed The third letter refers to the pacemaker’s response to a sensed event: T = Triggered D = Dual (inhibited and triggered*) I = Inhibited O = No response *In a single chamber mode, “triggered” means that when an intrinsic event is sensed, a pace is triggered immediately thereafter. In a dual chamber mode, “triggered” means that a sensed atrial event will initiate (trigger) an A-V delay. The fourth letter denotes the pacemaker’s programmability and whether it is capable of rate response: P = Simple Programmable (rate and/or output) M = Multiprogrammable (rate, output, sensitivity, etc.) C = Communicating (pacemaker can send/receive information to/from the programmer) R = Rate Modulation O = None Note that this sequence is hierarchical. In other words, it is assumed that if a pacemaker has rate modulation capabilities, “R”, that it also can communicate, “C”. The fifth letter represents the pacemaker’s antitachycardia functions: P = Pace D = Dual (pace and shock available) S = Shock O = None You may want to test the audience by having them describe different pacing modes. More modes and ECG strips are found in Module 2. O: None O: None O: None R: Rate modulating O: None S: Single (A or V) S: Single (A or V) O: None

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

www.hrsonline.org

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 1AVID Investigators. N Engl J Med. 1997;337:1576-1583

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.

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

Morphology Analysis

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

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

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

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

Pacemaker Presentations Failing to capture Pacing spikes – no capture Failing to sense Pacing occurs where it shouldn’t – 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!

Pacing - Tachyardia Failure to mode switch – tracking of atrial fibrillation/flutter with rapid paced ventricular rate Medications won’t control the rate Pacemaker Mediated Tachycardia Retrograde conduction to the atrium from a PVC starts a rapid pacing cycle via the pacemaker

Hysteresis

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 Clinical motivations by the device industry to develop unique algorithms (Search AV, AV Hysteresis, etc.) and/or pacing modes (AAISafeR etc.) to actively manage ventricular pacing were brought about by the well-understood relationship between the electrical-mechanical synchrony required by the heart to maintain optimal hemodynamic performance. Specifically, the atrial chamber contractions provide an important filling contribution to ventricular output. Coordinated pumping between the left and right ventricles is necessary to achieve adequate ejection fractions. When this AV synchrony and ventricular synchronization is lost, patients may suffer from poor systolic function and low cardiac output. JAMA. 2002;288(24):3115-3123

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

MVP Basic Operation DDD(R) Switch Figure: If your patient develops persistent loss of conduction, the device will automatically switch to DDD(R) operation, but continue to periodically look for restored conduction. Details on this switch provided in subsequent slides. DDD(R) Switch Ventricular support if loss of A-V conduction is persistent Image www.medtronic.com

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

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 manufacturer’s advisory may require urgent assessment also

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

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

Post-op Site Check

Hematoma

Post AICD Implant – 12 months

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

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

Leads Attached to Veins by Fibrotic Tissue

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

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.

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

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

Conclusion ≠

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

CRT requires wide complex ECG and Class II+ CHF