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Heart Rhythm Refresher Course 2014 Sudden Cardiac Death, Ventricular Arrhythmias and ICD Therapy ICD Implantation: Techniques and Trouble-shooting Dr Chan Kwok Keung Department of Medicine PYNEH, Hong Kong 6 Apr 2014 ICD Implantation: Techniques and Trouble-shooting 1. ICD implantation procedure (briefly on the standard procedure) 2. Special situations, trouble-shooting and management Venous access and lead placement What is Current of Injury (COI)? Defibrillation threshold (DFT) testing ICD: Conception 1966 Dr Mirowski ICD: Conception 1966 Over-the-counter electronic components ICD: First Human Implant 1980 Dr Winkle, Dr Mirowski, the first ICD patient, Dr Heilman ICD: First Human Implant 1980 A transvenous lead in SVC and a ventricular patch lead Evolution of ICD Therapy Benefits of ICD therapy: 1. Identify the target population 2. Implant the ICD successfully 3. Optimize the ICD programming ICD Implant Procedure (briefly) 1. 2. 3. Preparation for implant Consent. Model selection. Financial arrangement. Blood tests. Antibiotics prophylaxis. Defibrillation pads. The team and the necessary equipment. Venous access, pocket and lead placement Cephalic cut-down or subclavian/axillary puncture. Single or dual chamber ICD. Active or passive fixation. Lead testing DF-4 connector vs IS-1/DF-1 connector Assess P-wave/R-wave, pacing/defibrillation impedance, pacing threshold ICD Implant Procedure (briefly) 4. Defibrillation threshold (DFT) testing Sedation. VF induction by shock-on-T, burst stimulation, direct current shock. Rescue shock by external defibrillator standby. Intracardiac electrogram analysis. 5. Pocket closure. Postoperative care. Device programming. CXR. Drug adjustment. Subclavian Approach Cephalic Approach ICD Pocket DF-4 DF-1 DF-4 lead one connection between the lead and the device, with a single distal set screw to the tip electrode. more convenient and reduce header size. the use of spring contacts (IS-1/DF-1 connector use set screws to ensure high and constant contact pressure). High-and low-voltage applications in the same cavity (in IS-1/DF-1 devices, low- and high-energy contacts in separate cavities, embedded in nonconducting material). ICD implant ICD Implant Procedure: Complications 1. 2. General: cardiac, pulmonary, neurological,etc. Related to the ICD lead and pulse generator pocket hematoma (subclavian puncture) pneumothorax, hemothorax, subclavian artery puncture, air embolism, subclavian A-V fistula ICD system infection lead dislodgement, lead perforation, lead wire fracture/insulation break Venous thrombosis etc SPECIAL SITUATIONS, TROUBLE-SHOOTING AND MANAGEMENT Venous access and lead placement Special situations, trouble-shooting and management Venous access and lead placement (1): Persistent left superior vena cava ICD lead with long usable length active fixation mechanism Off SVC coil in DFT testing (SVC coil in posterior position) Alternative venogram approach: Right-side implant after Special situations, trouble-shooting and management Venous access and lead placement (2): Multiple ICD leads venogram active to confirm vein patency fixation mechanism desirable some separation in venous puncture site if feasible some separation between different ICD coils in multiple fluoroscopic views Special situations, trouble-shooting and management Venous access and lead placement (3): Right-side ICD implant Options available: Right-side implant after venogram Venoplasty Epicardial leads Subcutaneous ICD (S-ICD) Subcutaneous ICD (S-ICD) 45cm lead with good strength and durability 8-cm shocking coil, 2 sensing electrodes Electrode was positioned parallel to & 1-2cm to the left of sternal midline Pulse generator over the 6th rib between the mid- & anterior- axillary line 80-J shocks, up to 5 shocks, reverse shock polarity Bardy GH, et al.An entirelysubcutaneous ICD.NEJM 2010:363(1);36-44 Subcutaneous ICD (S-ICD) Limitations of S-ICD: 1.No conventional pacing capability (Post-shock pacing 200mA, 50ppm, maximum 30 seconds, demand-based) 2.No anti-tachycardia pacing (ATP) function 3.Unable 4.S-ICD to upgrade to CRT-D contraindicated for use with unipolar pacemakers Special situations, trouble-shooting and management Venous access and lead placement (4): Pacemaker RV lead perforation Active model fixation RV lead for a MRI compatible Emergency operation with intra-operative findings: RV pacing wire perforated via RV apex, then via pericardium and pleura; defect over pericardium 0.5cm; 1L blood and clots inside left pleural cavity. SPECIAL SITUATIONS, TROUBLE-SHOOTING AND MANAGEMENT Current of Injury What is Current of Injury (COI)? During implant procedure, injury to myocardium during lead placement as shown on intracardiac electrogram. More prominent in active lead than passive lead active fixation – helical screw into myocardium traumatically passive fixation – axial pressure on lead-myocardium interface Current of Injury (COI) COI at implant (RV passive lead) 10 minutes later… Current of Injury (COI) Active V lead. COI ST elevation A lead. COI ST elevation >5mV or >25% ST elevation >1mV or >25% ST elevation Passive >2mV >0.2mV Consider threshold values and COI COI subsides in 5-10 minutes usually Saxonhouse et al. Current of injury predicts adequate active lead fixation in permanent pacemaker/defibrilaltion leads. JACC 2005; 45(3): 412-7. Current of Injury (COI) COI confirms lead stability Active leads have more prominent COI than passive leads Lack of COI indicates increased risk of lead dislodgement COI with high pacing threshold: consider to recheck threshold 5-10 mins later before reposition. SPECIAL SITUATIONS, TROUBLE-SHOOTING AND MANAGEMENT Defibrillation threshold (DFT) testing Defibrillation Threshold (DFT) Testing. Is it necessary? 64,227 initial ICD implant between April to Dec 2010 in the NCDR Registry (National Cardiovascular Data ICD Registry; ~90% of all ICDs implanted in US) analyzed retrospectively. DFT testing not performed in 29% patients and more likely to have: - heart failure - lower LVEF atrial arrhythmias (e.g. AF) primary prevention indication CRT-D implant Russo AM, et al. Patient, physician and procedural factors influencing the use of DFT testing during initial ICD insertion. Pacing Clin Electrophysiol. 2013;36(12):1522-1531. DFT Testing. Is it necessary? ICD implant manuals approved by FDA include DFT testing. But 1.Better ICD devices nowadays and lead diagnostics without performing a shock. 2.Risks of DFT testing (0.016% mortality; 0.026% stroke/TIA) 3.Not guarantee clinically successful defibrillation (with heart failure, ischemia, electrolyte abnormalities). 4.Previous trial: No relationship between DFT testing and outcome in SCD-HeFT trial 1.Birnie D, et al. Complications associated with DFT testing: The Canadian experience. Heart Rhythm 2008;5:387-390. 2.Blatt JA, et al. No benefit from DFT testing in SCD-HeFT trial. J Cardiovasc Electrophysiol 2007; 4: S81. DFT Testing. Is it necessary? No consensus In real-world clinical practice, paradoxically, those sicker patients not having DFT testing may be most likely to benefit from testing. Ongoing Shockless Implant Evaluation (SIMPLE) trial (but not powered to evaluate mortality). “To test or not to test” vs “ For which patients is testing important” Defibrillation threshold (DFT) The minimum amount of energy required to reliably defibrillate the heart. Note: DFT is not a static value and may change over time, with drugs, and with disease progress. Successful defibrillation is probabilistic. So although the term threshold is used, there is no single energy level that is always successful clinically. Defibrillation Threshold (DFT) Testing Traditional practice: Perform 2 VF inductions with defibrillation energy 10J below the maximum device output (i.e. a 10-J safety margin; not actually the threshold). Alternative approach: Upper limit of vulnerability (ULV) is the lowest energy shock that does not induce VF when delivered during the vulnerable phase of ventricular repolarization. A 5-J ULV safety margin is suggested. High Defibrillation Threshold (DFT) Management 1. Rule out pneumothorax, loose set-screw 2. Reposition RV lead (to a more apical-septal position). Reverse polarity. Programmable waveform tilt/pulse width (if available) 3. High output device 4. Add SQ away/additional coils Add empiric sotalol/stop amiodarone Question Time ICD Trouble-shooting A 50-year-old man with dilated cardiomyopathy had a single-chamber ICD implanted for primary prevention indication. An active lead was placed at the RV septum due to poor sensing in RV apex. One week later, he presented to A&E Department for multiple ICD shocks while at home, asymptomatic. There is no change in medications and all blood tests were normal. CXR showed the lead was dislodged to the level of tricuspid annulus. ICD interrogation for one of the device shocks A shock (Rx1 Defib) was given for the device diagnosis of “VF”. Oversensing of the atrial signal by the ICD lead causing double counting and inappropriate shocks. DDx: 1.T wave oversense due to T wave amplitude/ morphology changes e.g. hyperkalaema 2.T wave oversense due to QT interval change e.g. antiarrhythmia drugs 3.Artefacts due to lead fracture 4.Electromagnetic interference The patient was admitted to Medical General ward. Due to tight CCL schedule, the lead revision was scheduled 3 days later. The patient had a cardiac arrest the day before operation and resuscitated. ICD interrogation for the last device shock VP VP Oversensing A signal (double counting) leads to inappropriate shock. The last device shock is proarrhythmic and causes VF. VF is not sensed by the ICD due to the low arrplitude of the ventricular electrogram. The ICD initiates ventricular pacing (VP) during VF. What will be your management for this patient with a dislodged ICD lead if you see her in medical ward as a cardiac consult? Deactivation of the ICD with intensive cardiac monitoring (e.g. CCU) until lead revision Arrange early lead revision asap. Summary Implant procedure Special situations: persistent Lt SVC, multiple leads, occluded subclavian vein, RV lead perforation Current of Injury during implant DFT testing and high DFT management END How Should I Program an ICD? Evidence and Experience 1. Basic ICD programmable parameters 2. Evidence from recent clinical trials 3. Summary Dr Chan Kwok Keung Department of Medicine PYNEH, Hong Kong 6 April 2014 Two goals for a therapy: 1. To help patients feel better 2. To help patients live longer or both. ICD improves survival, but at what cost? 1. Financial cost 2. Morbidity of ICD therapy complication of implant procedure device alert/recall, lead failure(not discussed) inappropriate therapy (appropriate but) unnecessary therapy affected by ICD programming and antiarrhythmic drugs. (this lecture will focus on ICD programming) Causes for inappropriate therapy (Shock or ATP) atrial arrhythmias (AF, atrial flutter, SVT) oversensing due to lead fracture noise or overcounting (T-wave oversensing, EMI, myopotentials) Causes for unnecessary therapy (Shock or ATP) Too aggressive treatment of VT than absolutely required shock or ATP for premature detection of non-sustained VT; premature ATP may accelerate NSVT Shock for sustained pace-terminable VT Implantable Cardioverter Defibrillator (ICD) ICD treats ventricular tachyarrhythmias Sensing Detection Therapy Sensing in ICD: A major challenge… A wide variation in the size of signals stable and large normal ventricular signals low amplitude VF signals Sensing in ICD Beat-to-beat auto-adjusting sensitivity Sensing in ICD Detection Ventricular Fibrillation (VF) Rate cut-off (VF zone) Number of intervals for detection (usually consecutive intervals not required; high sensitivity) Ventricular Tachycardia (VT) Rate cut-off [VT zone(s)] Number of intervals for detection Detection Enhancement/ SVT Discriminator Detection Enhancement Electrogram Morphology Current electrogram signal compared with stored normal template Match percentage = 1 - (area of difference) Detection Enhancement Stability To reduce inappropriate detection of atrial arrhythmias eg atrial fibrillation (rhythm not “stable” i.e. variable cycle length) Each interval compared to previous intervals Count as VT if the difference the programmed stability interval i.e. VT is “stable” VT detection interval: 500ms Stability 30ms Detection Enhancement Onset To reduce inappropriate detection of sinus tachycardia Average of current 4 intervals is compared to average of previous 4 intervals Current average programmed Previous average onset percentage i.e. onset is “sudden” in VT Detection Enhancement: Onset Onset percentage: 81% Dual-chamber ICD: SVT discriminator Dual-chamber ICD: SVT discriminator PR Logic – Pattern and Rate Analysis Discrimination of Lead Noise Caused by pace-sense conductor fracture, loose set screw, lead insulation breach. Therapy avoided by comparing near-field channel (RV tip to RV ring) to far-field channel (RV tip to Can/RV coil to Can). ICD Therapy 1. Defibrillation (in VF zone) Biphasic waveform high energy shock 2. Cardioversion (in VT zone) Synchronized biphasic waveform shock ranges from < 1J to high energy 3. Antitachycardia pacing (in VT zone) Attempt to terminate VT with rapid pacing Patient more comfortable and therapy energy-saving 4. Bradycardia pacing High-energy Defibrillation Monophasic Biphasic Biphasic waveforms are more effective than monophasic waveforms Capacitors act as high-voltage storage tanks. The battery can ‘pump’ energy into the capacitor which holds up the energy. So a 3.2V battery can fill a capacitor to ~30-36J (700-800V) to defibrillate the heart. Defibrillation threshold (DFT) The minimum amount of energy required to reliably defibrillate the heart. Note: DFT is not a static value and may change over time, with drugs, and with disease progress. Successful defibrillation is probabilistic. So although the term threshold is used, there is no single energy level that is always successful clinically. Probability of Successful Defibrillation and Shock Strength 125 % Success 100 75 50 25 0 0 5 10 Energy (Joules) 15 20 Low Energy Cardioversion For termination of ventricular tachycardia Shocks delivered at 0.1J up to several Joules, synchronized to R wave Shocks under 2J are much comfortable for patients Antitachycardia Pacing (ATP) Antitachycardia Pacing (ATP) ATP is not painful ATP consumes minimal amount of battery May be effective in some VTs, but may also be proarrhythmic PainFREE Rx 2 study: ATP terminated 73% of fast VT (18 of 24 intervals, 188250bpm). Wathen MS, et al. PainFREE Rx 2. Circulation 2004;110:2591-96. Evidence from recent trials Traditional Concept in the past Quick detection: the longer the arrhythmia, the more likely a patient to have symptoms e.g. syncope Lower cut-off rate: if a higher cut-off rate is used, a haemodynamically significant VT will be missed, leading to syncope or VF. But primary prevention indications were uncommon in the past. Is the ICD programming appropriate to the patient needs? Causes for inappropriate therapy (Shock or ATP) atrial arrhythmias (AF, atrial flutter, SVT) oversensing due to lead fracture noise or overcounting (T-wave oversensing, EMI, myopotentials) Causes for unnecessary therapy (Shock or ATP) Too aggressive treatment of VT than absolutely required shock or ATP for premature detection of non-sustained VT; premature ATP may accelerate NSVT Shock for sustained pace-terminable VT Reduction in Inappropriate Therapy and mortality through ICD Programming (MADIT-RIT trial) A randomized, single-blind, multicenter clinical study 1500 patients with either ischaemic or nonischaemic disease with an indication for a primary-prevention dualchamber ICD or CRTD. Patients with atrial fibrillation or device replacement excluded. Patients were assigned to one of three ICD programming groups with the primary objective of finding their rate of a first occurrence of inappropriate ATP or shocks. Moss A., etal. NEJM 2012; 367: 2275-83 MADIT-RIT: Three Treatment Arms Arm A (Conventional) Arm B (High-rate) Arm C (Duration-delay) Zone 1: 170 bpm, 2.5s delay Onset/Stability Detection Enhancements ON ATP + Shock Zone 1: 170 bpm Monitor only Zone 1: 170 bpm, 60s delay Rhythm ID Detection Enhancements ON ATP + Shock Zone 2: 200 bpm, 1s delay Quick Convert ATP Shock Zone 2: 200 bpm, 2.5s delay Quick Convert ATP Shock Zone 2: 200 bpm, 12s delay Rhythm ID Detection Enhancements ON ATP + Shock Zone 3: 250 bpm, 2.5s delay Quick Convert ATP + Shock NOTE: The ICD was not a new type of ICD. The programming choices were not new. Aim to ignore the slower tachyarrhythmias in High-rate and those of shorter duration in Duration-delay. MADIT-RIT Results During an average follow-up of 1.4 years, high-rate therapy and delayed ICD therapy, as compared with conventional device programming, associated with - reduction in a first occurrence of inappropriate therapy - reduction in all-cause mortality - no significant difference in adverse events e.g. syncope There was significant reduction by more than 70% of inappropriate therapy in both high-rate and delayed therapy groups Mortality was reduced by 55% in high-rate group (p=0.01) and by 44% in the delayed-therapy group (p=0.06). MADIT-RIT Lession: Treat sustained tachyarrhythmias only It does not favor quick detection and therapy. Note that in MADIT-RIT: •primary prevention indication only •dual-chamber ICD and CRT-D only •exclude AF patients. Effects of Long-detection Interval vs Standard-detection Interval for ICDs on Antitachycardia Pacing and Shock Delivery (ADVANCE III trial) A randomized, single-blind study to determine whether using 30 of 40 intervals to detect VT (long detection) reduces ATP and Shock compared with 18 of 24 intervals (standard detection). Patients with primary or secondary prevention, single- or dual-chamber ICD or CRT-D, sinus or AF. Gasparini M, et al. JAMA 2013; 309:1903-11 ADVANCE III trial Results: After a median follow-up of 1 year, the longdetection group had significantly less ICD therapies (ATP and shocks) and inappropriate shocks. There was significant hospitalizations. reduction in all-cause No difference in arrhythmia syncope and mortality. Lession: Broaden the long detection applicability to include secondary prevention, singlechamber ICD and AF patients. Inappropriate shock rates in patients with single chamber ICDs using a novel suite of detection algorithms (PainFree SST study) A non-randomized trial with primary endpoint of the rate of inappropriate shocks at one year post implant. Single chamber ICD, primary or secondary prevention, initial implant or replacement, sinus or AF. A special detection algorithm includes wavelet morphology analysis, discriminating T wave, assessment of lead integrity or noise and improved recognition of nonsustained episodes. Meijer A, et al. Europace June 2013 PainFree SST study Results 757 patients with single-chamber ICD 97.6% of patients free of inappropriate shocks during the first year post implant. Lession: reducing inappropriate shock rate below 3% at 1 year is possible Programming ICDs in patients with primary prevention indication to prolong time to first shock (PROVIDE study) A randomized study of primary prevention ICD (single or dual chamber or CRTD) in 1670 patients. A combination of programmed parameters (higher detection rates, longer detection intervals, empiric ATP, SVT discriminators) vs conventional parameters. Result: reduced ICD therapies without increasing arrhythmic syncope and reduced all-cause mortality. Saeed M, et al. J Cardiovasc Electrophysiol 2014; 25(1): 52-59 Safety and efficacy of strategic ICD programming to reduce shock delivery burden in a primary prevention patient population A non-randomized retrospective analysis of 300 ICD patients of various manufacturers. Strategic ICD programming to reduce shocks. 64% risk reduction in primary endpoint (composite of death and appropriate shocks) and 70% reduction in inappropriate shocks. Buber J, et al. Europace 2014; 16(2): 227-234 The impact of prolonged arrhythmia detection times on outcomes: a meta-analysis 4896 patients from PROVIDE, RELEVANT. MADIT-RIT, ADVANCE 3, Reduced mortality by 23% Reduced inappropriate shocks and both appropriate and inappropriate ATP significantly. Scott PA, et al. Heart Rhythm 2014; D01: 10.1016. Abstract. Summary 1. ICD therapy has morbidity. The benefits of an ICD are greatly affected by its programming 2. Avoid inappropriate therapy and unnecessary therapy (less pain, less hospitalization, better QOL, improved survival). 3. To be certain that there is a sustained tachyarrhythmia before treating the rhythm prolonged duration of arrhythmia detection faster rate of arrhythmia detection use of ATP algorithms for discrimination of SVT END