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    1. S ALLEN 06 How to programme and follow up a pacemaker BCS Glasgow 2006 Technical Aspects of a Pacemaker Mr Stuart Allen. Southampton General Hospital.

    2. S ALLEN 06

    3. S ALLEN 06 Goals of a Pacemaker Clinic Technical & Physiological Satisfy BPEG/HRuk Guidelines Electrical characteristics/Battery Check Histograms/Diagnostics/ Arrhythmia analysis/evaluation Physiological needs of patient Prediction of potential problems Clinical/electrical Troubleshooting Majority of patients fall in to the category of routine follow up

    4. S ALLEN 06 Common Referrals for Pacemaker Checks My SHO/Registrar told me to ask for it! No Pacing spikes on ECG. Patient has a pacemaker implanted. Can we check it? (no other reason given) Syncope/Dizzy Spells/Palpitations. ?Pacemaker working. If the ECG shows normal pacing and the patient is free of any symptoms there is unlikely to be a pacemaker/lead problem Pre/ Post surgery Augment cardiac output .

    5. S ALLEN 06 Pacemakers can help answer key clinical questions regarding device status, clinical status and arrhythmia status of the patient. Pacemakers can give useful insight into disease progression and long-term patient management questions. Ask the right questions!

    6. S ALLEN 06 Stimulate cardiac depolarization Sense intrinsic cardiac function Respond to increased metabolic demand by providing rate responsive pacing Provide diagnostic information stored by the pacemaker Most Pacemakers Perform Four Functions:

    7. S ALLEN 06 Potential Problems Identifiable on an ECG Can Generally Be Assigned to Five Categories: Undersensing Oversensing Noncapture No output (Pseudomalfunctions) The causes of undersensing, oversensing, noncapture, lack of output, and pseudomalfunctions vary. However, each of these anomalies compromises the pacemakers ability to supplement intrinsic conduction. The causes of undersensing, oversensing, noncapture, lack of output, and pseudomalfunctions vary. However, each of these anomalies compromises the pacemakers ability to supplement intrinsic conduction.

    8. S ALLEN 06 Paced Rhythm Recognition

    9. S ALLEN 06 Electrical Characteristics Lead threshold(s) Lead Impedance(s) Sensing threshold(s) Battery voltage/Current drain Battery impedance Longevity

    10. S ALLEN 06 Typical Follow-Up Activities In current practice, pacing thresholds are assessed periodically, typically every 6 to 12 months. Threshold testing is time consuming, representing one-quarter or more of the time spent during a typical follow-up visit. In addition, the efficiency of threshold testing is dependent upon the clinical experience of the those involved. Overall, those with more experience are able to shorten the time it takes for threshold testing. In addition, such periodic assessment of thresholds doesnt reflect possible changes that may occur between office visits, such as changes in drugs or drug dosage or physiologic changes due to diabetes or other disease processes.In current practice, pacing thresholds are assessed periodically, typically every 6 to 12 months. Threshold testing is time consuming, representing one-quarter or more of the time spent during a typical follow-up visit. In addition, the efficiency of threshold testing is dependent upon the clinical experience of the those involved. Overall, those with more experience are able to shorten the time it takes for threshold testing. In addition, such periodic assessment of thresholds doesnt reflect possible changes that may occur between office visits, such as changes in drugs or drug dosage or physiologic changes due to diabetes or other disease processes.

    11. S ALLEN 06

    12. S ALLEN 06 Stimulation Threshold The minimum output pulse needed to consistently capture the heart

    13. S ALLEN 06 Threshold Trending

    14. S ALLEN 06 Sensitivity The degree that the pacing system sees or senses signals, controlled by the sensitivity setting which is graduated in millivolts (mV)

    15. S ALLEN 06 Undersensing An intrinsic depolarization that is present, yet not seen or sensed by the pacemaker An intrinsic depolarization occurs in the atrium, but this depolarization is not sensed by the pacemaker. Therefore, the pacemaker sends an inappropriate pacing pulse to that chamber. Undersensing can be thought of as overpacing. In this example, an AAI pacemaker is programmed to inhibit the atrial pacing pulse when a P-wave is sensed. Because the P-wave was not sensed, the pacemaker delivered an atrial pulse. If a pacemaker is undersensing, you will not see appropriate atrial sense markers on the marker channel. An intrinsic depolarization occurs in the atrium, but this depolarization is not sensed by the pacemaker. Therefore, the pacemaker sends an inappropriate pacing pulse to that chamber. Undersensing can be thought of as overpacing. In this example, an AAI pacemaker is programmed to inhibit the atrial pacing pulse when a P-wave is sensed. Because the P-wave was not sensed, the pacemaker delivered an atrial pulse. If a pacemaker is undersensing, you will not see appropriate atrial sense markers on the marker channel.

    16. S ALLEN 06 Undersensing May Be Caused By: Inappropriately programmed sensitivity Lead dislodgment Lead failure: Insulation break; conductor fracture Lead maturation Change in the native signal Insulation breaks may cause undersensing if the insulation break results in the: Reduction of intrinsic beats at the sense amplifier Inability of the amplitude to meet the sensitivity requirement Conductor fracture may cause an open circuit. If intrinsic signals cannot cross the conductor fracture, undersensing will occur. The primary cause of conductor fracture is the chronic stress imposed on the lead as a result of its placement in the subclavian region, and may be reflected in increased impedance readings. During the first week following lead implantation, the amplitude and slew rate may abruptly decline; these values increase to approach implantation values after about 6-8 weeks as the lead matures.1 (Steroid-eluting leads may eliminate the reduction in sensitivity by minimizing the growth of fibrotic tissue near the electrode). Lead dislodgment usually occurs early in the life of the pacemaker before the lead has fibrosed to endocardial tissue. The primary causes of lead dislodgment are: Inadequate initial positioning Patient movement (bringing arms overhead, etc.) Secondary intervention rates for lead dislodgement should be below 2% for ventricular leads and 3% for atrial leads.2 One recent clinical trial reported a lead dislodgement rate of 2.2%.2 Changes in the native signal may be caused by: Myocardial infarction Change in medications (not common) Electrolyte imbalance Undersensing may be caused by an inappropriately programmed setting. 1Hayes DH. Cardiac Pacing and Defibrillation: A Clinical Approach. Armonk, NY: Futura Publishing Company; 2000. Page 453. 2Link MS et al. Complications of dual chamber pacemaker implantation in the elderly. Pacemaker Selection in the Elderly (PASE) Investigators. J Interv Card Electrophysiol. 2:175-179, 1998.Insulation breaks may cause undersensing if the insulation break results in the: Reduction of intrinsic beats at the sense amplifier Inability of the amplitude to meet the sensitivity requirement Conductor fracture may cause an open circuit. If intrinsic signals cannot cross the conductor fracture, undersensing will occur. The primary cause of conductor fracture is the chronic stress imposed on the lead as a result of its placement in the subclavian region, and may be reflected in increased impedance readings. During the first week following lead implantation, the amplitude and slew rate may abruptly decline; these values increase to approach implantation values after about 6-8 weeks as the lead matures.1 (Steroid-eluting leads may eliminate the reduction in sensitivity by minimizing the growth of fibrotic tissue near the electrode). Lead dislodgment usually occurs early in the life of the pacemaker before the lead has fibrosed to endocardial tissue. The primary causes of lead dislodgment are: Inadequate initial positioning Patient movement (bringing arms overhead, etc.) Secondary intervention rates for lead dislodgement should be below 2% for ventricular leads and 3% for atrial leads.2 One recent clinical trial reported a lead dislodgement rate of 2.2%.2 Changes in the native signal may be caused by: Myocardial infarction Change in medications (not common) Electrolyte imbalance Undersensing may be caused by an inappropriately programmed setting. 1Hayes DH. Cardiac Pacing and Defibrillation: A Clinical Approach. Armonk, NY: Futura Publishing Company; 2000. Page 453. 2Link MS et al. Complications of dual chamber pacemaker implantation in the elderly. Pacemaker Selection in the Elderly (PASE) Investigators. J Interv Card Electrophysiol. 2:175-179, 1998.

    17. S ALLEN 06 Oversensing The sensing of an inappropriate signal Can be physiologic or non-physiologic If a pacemaker is oversensing, you will see signals on the marker channel that do not correspond to the ECG pattern. In this example, the pacemaker recorded a ventricular pulse on the marker channel. However, no activity was demonstrated on the ECG strip. Pauses or intervals longer than the programmed lower rate will occur in single chamber systems. Dual chamber systems may show tracking at the upper rate with atrial oversensing. This ECG exhibits oversensing that may be attributed to: Lead insulation failure (a decrease in lead impedance will be seen) Make-and-break fracture A lead connection problem (Note: The information below transitions into the next slide.) Insulation failurea common cause of oversensingoccurs when myopotentials are detected at the site of the insulation break. Lead fracture is another common cause of oversensing. As the frayed ends of conductor wires make and break contact, the pacemaker senses these make and break signals, which results in oversensing. Oversensing may also occur if the lead is loose in the connector block.If a pacemaker is oversensing, you will see signals on the marker channel that do not correspond to the ECG pattern. In this example, the pacemaker recorded a ventricular pulse on the marker channel. However, no activity was demonstrated on the ECG strip. Pauses or intervals longer than the programmed lower rate will occur in single chamber systems. Dual chamber systems may show tracking at the upper rate with atrial oversensing. This ECG exhibits oversensing that may be attributed to: Lead insulation failure (a decrease in lead impedance will be seen) Make-and-break fracture A lead connection problem (Note: The information below transitions into the next slide.) Insulation failurea common cause of oversensingoccurs when myopotentials are detected at the site of the insulation break. Lead fracture is another common cause of oversensing. As the frayed ends of conductor wires make and break contact, the pacemaker senses these make and break signals, which results in oversensing. Oversensing may also occur if the lead is loose in the connector block.

    18. S ALLEN 06 Noncapture May Be Caused By: Lead dislodgment Lead perforation Low output Lead maturation Poor connection in the header Lead failure In addition to lead dislodgment, lead perforation should be considered as a potential cause of noncapture with acute implants. A poor connection at the connector block usually occurs because the lead has been inadequately secured at implant. The poor connection may be viewed radiographically. As a lead matures and becomes surrounded by fibrotic tissue, the threshold of stimulation decreases, which may result in noncapture.In addition to lead dislodgment, lead perforation should be considered as a potential cause of noncapture with acute implants. A poor connection at the connector block usually occurs because the lead has been inadequately secured at implant. The poor connection may be viewed radiographically. As a lead matures and becomes surrounded by fibrotic tissue, the threshold of stimulation decreases, which may result in noncapture.

    19. S ALLEN 06 Less Common Causes of Noncapture May Include: Twiddlers syndrome Electrolyte abnormalities e.g. hyperkalemia Myocardial infarction Drug therapy Battery depletion Exit block Twiddlers syndrome can be identified radiographically. Hyperkalemia, an electrolyte abnormality, is defined by a high serum potassium level and is commonly caused by kidney disease. Hyperkalemia may affect the stimulation threshold. If a myocardial infarction occurs near the tip of the lead, an increase in the stimulation threshold and/or noncapture may occur. Drug therapy may affect capture thresholds and result in significant changes from the patients baseline. If the delivered voltage is significantly reduced, advanced stages of battery depletion may result in noncapture. Exit block occurs when the stimulation threshold exceeds the pacemakers maximum output. Twiddlers syndrome can be identified radiographically. Hyperkalemia, an electrolyte abnormality, is defined by a high serum potassium level and is commonly caused by kidney disease. Hyperkalemia may affect the stimulation threshold. If a myocardial infarction occurs near the tip of the lead, an increase in the stimulation threshold and/or noncapture may occur. Drug therapy may affect capture thresholds and result in significant changes from the patients baseline. If the delivered voltage is significantly reduced, advanced stages of battery depletion may result in noncapture. Exit block occurs when the stimulation threshold exceeds the pacemakers maximum output.

    20. S ALLEN 06 Non Capture due to Atrial Lead Displacement

    21. S ALLEN 06 Lead Impedance Measurement High Lead Impedance Open Circuit e.g. lead not connected to device (Set Screw) Lead fracture Low Lead Impedance Partial lead/insulation break fluid ingress Fluid/blood in header

    22. S ALLEN 06 An Insulation Break Around the Lead Wire Can Cause Impedance Values to Fall Insulation breaks expose the wire to body fluids which have a low resistance and cause impedance values to fall Current drains through the insulation break into the body which depletes the battery An insulation break can cause impedance values to fall below 300 ohms Insulation around the lead wire prevents current loss from the lead wire. Electrical current seeks the path of least resistance. An insulation break that exposes wire to body fluids which have low resistance causes: Lead impedance to fall Current to drain into the body Battery depletion Impedance values below 300 W. Insulation breaks are often marked by a trend of falling impedance values. An impedance reading that changes suddenly or one that is >30% is considered significant and should be watched closely.Insulation around the lead wire prevents current loss from the lead wire. Electrical current seeks the path of least resistance. An insulation break that exposes wire to body fluids which have low resistance causes: Lead impedance to fall Current to drain into the body Battery depletion Impedance values below 300 W. Insulation breaks are often marked by a trend of falling impedance values. An impedance reading that changes suddenly or one that is >30% is considered significant and should be watched closely.

    23. S ALLEN 06 A Wire Fracture Within the Insulating Sheath May Cause Impedance Values to Rise Impedance values across a break in the wire will increase Current flow may be too low to be effective Impedance values may exceed 3,000 ohms Insulation may remain intact but the wire may break within the insulating sheath. Impedance may exceed 3,000 W. Current flow may be too low to be effective. If a complete fracture of the wire occurs: No current will flow Impedance number will be infinite When suspecting a wire break, look for a trend in an increase in impedance values rather than a single lead impedance value. Insulation may remain intact but the wire may break within the insulating sheath. Impedance may exceed 3,000 W. Current flow may be too low to be effective. If a complete fracture of the wire occurs: No current will flow Impedance number will be infinite When suspecting a wire break, look for a trend in an increase in impedance values rather than a single lead impedance value.

    24. S ALLEN 06 Normal Impedance Trend

    25. S ALLEN 06 High Lead Impedance indicating possible lead fracture

    26. S ALLEN 06 Pseudomalfunctions Pseudomalfunctions are defined as: Unusual Unexpected ECG findings that appear to result from pacemaker malfunction but that represent normal pacemaker function eg Pacemaker Mediated Tachycardia (PMT). Pseudomalfunctions should be ruled out as the cause(s) of an anomalous ECG strip before corrective measures are taken. Pseudomalfunctions should be ruled out as the cause(s) of an anomalous ECG strip before corrective measures are taken.

    27. S ALLEN 06

    28. S ALLEN 06 Automatically included on this initial interrogation report Pacemaker Diagnostics Lead Monitoring Unique to the Medtronic Kappa 900, the Initial Interrogation Report automatically includes real-time telemetry reporting the lead status report as well as the measured lead impedance. If a polarity switch were to occur, the Kappa 900 would note it here and in Significant Events on the Quick Look screen. Unique to the Medtronic Kappa 900, the Initial Interrogation Report automatically includes real-time telemetry reporting the lead status report as well as the measured lead impedance. If a polarity switch were to occur, the Kappa 900 would note it here and in Significant Events on the Quick Look screen.

    29. S ALLEN 06 Diagnostics, Histograms & Arrhythmia analysis The EnPulse Pacing System has simplified the follow-up process by providing instant insight and access to all of the information needed to complete a routine follow-up on one screen. All of the information provided by the Quick Look II screen is also made available (automatically) in printed format via the Initial Interrogation Report. It is estimated that 90% of pacemaker patients fall into the category of routine follow-up. When Observations suggest that further investigation is warranted and/or troubleshooting is required, access to more detailed information can be found through the use of the Quick Link [>>] icons or via the Main Icons listed on the right-hand side of the display.The EnPulse Pacing System has simplified the follow-up process by providing instant insight and access to all of the information needed to complete a routine follow-up on one screen. All of the information provided by the Quick Look II screen is also made available (automatically) in printed format via the Initial Interrogation Report. It is estimated that 90% of pacemaker patients fall into the category of routine follow-up. When Observations suggest that further investigation is warranted and/or troubleshooting is required, access to more detailed information can be found through the use of the Quick Link [>>] icons or via the Main Icons listed on the right-hand side of the display.

    30. S ALLEN 06 AF Verified Effect on Ventricular Rate suspected Atrial High Rate Episode Key Points: The Atrial High Rate Episodes diagnostic summary and trends provide information to verify that the patient indeed experienced AF. Episode duration is noted: 0% of patient time, only 1 episode lasted >1 minute The Episode Onset Trend shows high atrial and ventricular rates at onset. Amiodarone initiated and cardioversion was performed. Normal Sinus Rhythm was restored. We still dont know: Did AF affect the HF trends? Does heart failure beget AF? Over of patients with heart failure develop AF; AF is more often a result of HF rather than a cause of HF; There is no evidence to suggest that cardiac resynchronization causes or diminishes AF.Key Points: The Atrial High Rate Episodes diagnostic summary and trends provide information to verify that the patient indeed experienced AF. Episode duration is noted: 0% of patient time, only 1 episode lasted >1 minute The Episode Onset Trend shows high atrial and ventricular rates at onset. Amiodarone initiated and cardioversion was performed. Normal Sinus Rhythm was restored. We still dont know: Did AF affect the HF trends? Does heart failure beget AF? Over of patients with heart failure develop AF; AF is more often a result of HF rather than a cause of HF; There is no evidence to suggest that cardiac resynchronization causes or diminishes AF.

    31. S ALLEN 06 Ventricular Rate Histogram During Atrial High Rate Episodes Evaluate: Rate Distribution Time in High Rate V-pace vs. V-sense Ventricular Histogram The Ventricular Rate Histogram During Atrial High Rate Episodes Diagnostic clearly supports the supposition that high ventricular rates may be the source of the patients discomfort. Recall that the Upper Tracking Rate is programmed to 120 ppm, hence the majority (76.7%) are ventricular sensed events, many of which are between 100 and 140 ppm. In this screen, Ventricular Rate Histogram during Atrial High Rate Episodes, it shows 76.7% VS Beats. To find out if these beats are considered Ventricular Sensing Episodes (VSE) and if they triggered a Ventricular Sense Response (VSR); one must evaluate the Ventricular Rate Histogram. How much pacing is the patient receiving? How many VSR did the patient have? Once you gather that information you can evaluate the efficacy of CRT during the AF episodes. The Ventricular Rate Histogram During Atrial High Rate Episodes Diagnostic clearly supports the supposition that high ventricular rates may be the source of the patients discomfort. Recall that the Upper Tracking Rate is programmed to 120 ppm, hence the majority (76.7%) are ventricular sensed events, many of which are between 100 and 140 ppm. In this screen, Ventricular Rate Histogram during Atrial High Rate Episodes, it shows 76.7% VS Beats. To find out if these beats are considered Ventricular Sensing Episodes (VSE) and if they triggered a Ventricular Sense Response (VSR); one must evaluate the Ventricular Rate Histogram. How much pacing is the patient receiving? How many VSR did the patient have? Once you gather that information you can evaluate the efficacy of CRT during the AF episodes.

    32. S ALLEN 06 Patient Presenting with TIA 12 lead ECG shows NSR/ 24hr Holter monitor NAD

    33. S ALLEN 06 Patient Presenting With Syncope

    34. S ALLEN 06 Physiological Programming Rate & Rate Response Promotion of intrinsic conduction Anti Arrhythmic functions

    35. S ALLEN 06 Rate Responsive Pacing When the patients exercise increases, the pacemaker ensures that the heart rate increases to provide additional cardiac output

    36. S ALLEN 06 A Variety of Rate Response Sensors Exist Those most accepted in the market place are: Activity sensors that detect physical movement and increase the rate according to the level of activity Minute ventilation sensors that measure the change in respiration rate and tidal volume via transthoracic impedance readings Blended sensor of activity+MV QT interval Sensitivity of the Rate Response sensor can be set in each patient Other sensors that measure QT interval, central venous temperature, stroke volume, etc., are largely investigational devices or have gained limited acceptance.Other sensors that measure QT interval, central venous temperature, stroke volume, etc., are largely investigational devices or have gained limited acceptance.

    37. S ALLEN 06 Right ventricular (RV) pacing alters the normal myocardial electrical activation sequence leading to regional wall motion abnormalities of the left ventricle (LV). Histopathologic abnormalities of the myocardium have been identified with prolonged ventricular pacing of the mature and immature heart. Why Promote Intrinsic Conduction

    38. S ALLEN 06 Promoting Intrinsic Conduction Programming AV interval (Search AV)

    39. S ALLEN 06 Arrhythmia Management Atrial Pacing Preference for suppression of APCs that may cause AF Anti Tachycardia pacing for Atrial flutter Ventricular Rate Regulation for AF

    40. S ALLEN 06 The future. Remote Patient Management Internet-based system providing full device interrogation data: All programmed parameters Stored episodes with electrograms 10 second electrogram captured at interrogation All reports available on programmer available for display and printing Medtronic CareLink Monitor Transmits ICD information via analog telephone line from any location to secure server Medtronic CareLink Clinician Website Allows clinician to access server from any location via Internet to review ICD information Provides ICD information similar to that obtained during in-office follow-up Medtronic CareLink Patient Website Provides a credible resource for accurate device and disease education as well as psychosocial support materials Allows patients to review a subset of their ICD information (with physician approval) Medtronic CareLink Monitor Transmits ICD information via analog telephone line from any location to secure server Medtronic CareLink Clinician Website Allows clinician to access server from any location via Internet to review ICD information Provides ICD information similar to that obtained during in-office follow-up Medtronic CareLink Patient Website Provides a credible resource for accurate device and disease education as well as psychosocial support materials Allows patients to review a subset of their ICD information (with physician approval)

    41. S ALLEN 06 Thank You