The Electrical Management of Cardiac Rhythm Disorders Tachycardia Implant Procedures

1. The Electrical Management of Cardiac Rhythm DisordersTachycardiaImplant Procedures The Electrical Management of Cardiac Rhythm Disorders, Tachycardia, Slide Presentation 20 Implant ProceduresThe Electrical Management of Cardiac Rhythm Disorders, Tachycardia, Slide Presentation 20 Implant Procedures

2. ICD Implant Overview Today�s ICDs are implanted in much the same way a pacemaker is implanted Transvenous leads Pectoral implant Sometimes done on outpatient basis May require only conscious sedation Device-based testing may be done to test defibrillation thresholds (DFTs)

3. Before the Implant Interrogate the device Be sure to verify that battery voltage > 3.2 V Check charge times Perform a capacitor maintenance charge If desired, enter patient data into device ICD will store patient�s name, diagnosis, device and lead information Very valuable if patient is seen by other physicians, travels a lot, may be treated out-of-clinic Defibrillation is OFF in the device as shipped; verify this for the safety of the implant team!

4. Basic Preparations Heart monitor Pulse oximeter Oxygen delivery system Blood pressure monitor External defibrillation equipment Anesthesia equipment The stylized ECG says help. It is a reminder that there should always be external defibrillation equipment and trained personnel on hand during an ICD implant.The stylized ECG says help. It is a reminder that there should always be external defibrillation equipment and trained personnel on hand during an ICD implant.

5. Markers of High DFTs Although it is impossible to accurately predict DFTs prior to testing, there are indicators or markers that suggest high DFTs Cardiomyopathy Low ejection fraction (if known) Antiarrhythmic agents High NYHA Class Prior myocardial infarction (MI) High DFTs can (and do) occur in patients without these markers, too!

6. Patient�s Diagnosis Is this ICD for primary prevention? Patient is at high risk for SCD but has no documented history of arrhythmia This does not affect the implant procedure but will affect programming Primary-prevention therapy is typically one-zone (VF only) Is this ICD for secondary prevention? Patient has a history of arrhythmias This does not affect the implant, but does affect programming Need zones to accommodate known rhythm disorders Does the patient have a standard pacing indication? Again, affects how the device will be programmed

7. Single-Chamber versus Dual-Chamber A single-chamber system requires one lead (RV) RV lead both senses/paces and shocks A dual-chamber system requires two leads (RA and RV) RA lead senses/paces only RV lead both senses/paces and shocks Other tools Introducers (based on size of leads and techniques) Guide wires, stylets Pacing System Analyzer (PSA) Measures mode, rate, pacing parameters perioperatively

8. During the Implant Leads are implanted first Single-stick or dual-stick technique Cephalic cutdown or subclavian stick are most common approaches Venous access may be more lateral in ICD implantation than for pacemaker implantation Typically, the ventricular lead is placed first RV apex RV outflow tract

9. Thresholds and Impedance Once the leads are in place, thresholds should be tested Lead impedance values should be evaluated (and fall within the specified range, ideally in the middle)

10. Securing the Leads First, verify appropriate sensing and pacing Suture the lead(s) in place using the suture sleeve Plug the lead pins into the epoxy header (the device indicates which lead goes into which port) Assure electrical connection by making sure the lead is properly in place (set-screw)

11. Implant Testing Implant testing should be done with the actual device ICD should be in the pocket Requires a patient care system Use wireless telemetry (if available) Or put wand in sterile bag for introduction into the field Obtain a real-time EGM This shows what the ICD �sees� from signals picked up by the leads Look for these landmarks Strong, clear intrinsic signals Possible far-field sensing

12. Perioperative Real-Time EGM

13. Real-Time Measurements Obtain real-time measurements from the device Shows what the device is actually doing (not what it is programmed to do) Battery voltage (should have a BOL value) Signal amplitudes Should be large enough for proper sensing Verify sensitivity settings correspond to these signal sizes Pacing lead impedance Should fall within the broad range specified by the manufacturer Values should be near middle of range (not at either extreme)

14. High-Voltage Lead Integrity Check Verifies proper lead connection and set up (without delivering a high-energy shock) 12 V through RV lead Most patients will feel this and perceive it as painful May require anesthesia Warn the patient before conducting this test ICD can be programmed to do daily HV lead integrity checks automatically using a multivector system

15. HV Lead Integrity Check

16. DFT Testing DFT is the lowest amount of energy required to reliably defibrillate the heart DFTs vary by patient and will vary in one patient over time Conventional safety margin is 10 J Patient is tested to have DFT of 13 J Program device to 23 J (13 + 10 J safety margin) DFT testing requires VF induction and therapy delivery from the device Device-based testing can induce the arrhythmia External equipment can also be used

17. Device-Based Arrhythmia Induction Device-based testing (DBT) allows Burst pacing (programmed stimulation protocol) Shock-on-T DC Fibber DC Fibber (also known as Ventricular Fibber) uses 12 V of direct current Works 96.4% of the time on the first application Will not awaken a patient out of conscious sedation Easy to set up and activate Once arrhythmia is induced, use device to detect, diagnose, and deliver therapy

18. DFT Testing Always have external defibrillation equipment available and ready to use during DFT testing Make sure trained personnel are there to defibrillate externally, if required Always alert the team before arrhythmia induction and DFT testing Once test is over, check diagnostic data to confirm proper function (can take a few minutes for data to be available)

19. DFT Testing Considerations DFT testing is painful; make sure the patient is properly sedated or anesthetized Confirm that the ICD is appropriately programmed Ideally, set up two shocks One lower-energy, the second maximum energy During DFT testing, watch detection and therapy delivery on the programmer If you need to do DFT testing again, allow at least three minutes Give �stunned� tissue time to recover

20. Implant Troubleshooting: Impedance High intraoperative lead impedance Suggests lead is not properly connected Verify leads are plugged in and set-screws are tightened Make sure leads are in the right ports Low intraoperative lead impedance Suggests that there is an �open circuit� May be a lead insulation break Check insulation for nicks or cuts Look for possible lead damage (particularly if passing two leads)

21. Implant Troubleshooting: High DFTs High DFTs Use programmable fixed pulse width Use programmable tilt Reverse the polarity Change the shocking vector Reposition the lead Playing the odds�DFT problems are more likely to be solved with Programmable fixed pulse width (rather than tilt) RV anode (rather than RV cathode)

22. Conclusion ICD implants today Pectoral implants with transvenous leads Often done under conscious sedation May be performed on out-patient basis Steps Venous access Lead placement/testing Capture and sensing thresholds Device testing High DFTs can be a challenge Close pocket/final programming