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Trouble shoooting ICD AND CRT

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CRT AND ICD TROUBLE SHOOTING

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Trouble shoooting ICD AND CRT

  1. 1. Introduction  ICD are the cornerstone in the prevention of sudden death both in patients at risk of life-threatening ventricular arrhythmias with or without heart failure ---primary prevention  in patients rescued from non-tolerated VT or ventricular fibrillation -- secondary prevention  Therapy delivered for causes other than VT/VF is termed “inappropriate”, and has been reported to occur in up to 17% of patients of heart failure patients  Shock delivery, whether appropriate or inappropriate, has been reported to negatively impact patient survival, being closely associated to progressive pump failure TROUBLE SHOOTING OF ICD & CRT
  2. 2. ICD TROUBLE SHOOTING  Evaluating patient with shocks  Evaluating ineffective / absent treatment  Preentive programming TROUBLE SHOOTING OF ICD & CRT
  3. 3. Clinical presentation four categories:  Shocks (appropriate, inappropriate or failure to deliver therapy)  Dizziness/syncope  Palpitations  Alerts (audible beeps or sensed vibrations originating from the ICD) TROUBLE SHOOTING OF ICD & CRT
  4. 4. Avoiding Shocks Is Important To Reduce Pain and Anxiety and Increase Device Acceptance1 To Reduce Healthcare Burden and Improve Patient Quality of Life1 Avoiding Shocks May Improve Survival/Heart Failure2 1 Wathen MS, DeGroot PJ, Sweeney MO, et al, for the PainFREE Rx II Investigators. Prospective randomized multicenter trial of empirical antitachycardia pacing versus shocks for spontaneous rapid ventricular tachycardia in patients with implantable cardioverter-defibrillators: Pacing Fast Ventricular Tachycardia Reduces Shock Therapies (PainFREE Rx II) trial results. Circulation. October 26, 2004;110(17):2591-2596. 2 Sweeney MO, et al. Differences in effects of electrical therapy type on health care utilization in the MVP ICD Trial. Presented at HRS 2010. TROUBLE SHOOTING OF ICD & CRT
  5. 5. APPROACH TO A PATEINT WITH SHOCKS TROUBLE SHOOTING OF ICD & CRT
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  8. 8. APPROACH TO A PATEINT WITH SHOCKS  When a patient presents with an ICD shock, a focused history and device interrogation should be performed.  Symptoms of palpitations/dyspnea/near-syncope prior to the shock go in favor of an appropriate shock.  A shock “out of the blue” should make one alert for the possibility of an inappropriate shock. TROUBLE SHOOTING OF ICD & CRT
  9. 9.  The two primary ICD EGMs are the shock or high-voltage EGM displayed on the shock channel and the ventricular sensing EGM displayed on the sensing channel .  The marker channel indicates the timing of sensing EGM that reachs the amplitude threshold for a sensed event.  The sensing EGM records a local (near-field) ventricular signal between the tip electrode and the adjacent ring or RV coil.  EGM recorded between the tip and the RV coil is referred to as integrated bipolar EGM because the RV coil integrates both pace-sense and defibrillation functions.  recorded between the tip and a small proximal ring electrode are referred to as dedicated (or true) bipolar EGM because the ring electrodeis dedicated to pacing and sensing, not used for defibrillation.  Leads designed for integrated bipolar sensing do not require a ring electrode and are thus simpler than those designed for dedicated bipolar sensing. TROUBLE SHOOTING OF ICD & CRT
  10. 10. Implantable cardioverter defibrillator (ICD) leads and electrograms (EGMs). Charles D. Swerdlow et al. Circ Arrhythm Electrophysiol. 2014;7:1237-1261 Copyright © American Heart Association, Inc. All rights reserved.
  11. 11.  The shock EGM records a more global (far-field) signal between widely separated, high-voltage electrodes, most commonly RV coil and generator housing (can).  In analyzing ventricular sensing, the shock EGM is used as a check on the sensing EGM: signals sensed on the sensing channel that do not correspond to signals on the shock channel indicate oversensing.  Dual-coil leads permit recording additional far-field signals, including the shock EGM between RV and SVC coils and the leadless ECG between the can and SVC coil.  The left ventricular EGM in CRT-Ds provides another check on ventricular sensing. TROUBLE SHOOTING OF ICD & CRT
  12. 12. TACHYARRHYTHMIAS  after an episode, the retrieved signals are judged not to be due to oversensing but to an actual tachycardia, further evaluation of the arrhythmia has to be performed to verify appropriateness of the shock since SVT-VT discrimination algorithms are not always perfect.  High ventricular rates during atrial fibrillation or atrial flutter are the most frequent causes of inappropriate detection and therapy  The Flashback memory (Medtronic) or Trending feature (Boston Scientific) may provide helpful information to discriminate between the different supraventricular arrhythmias. TROUBLE SHOOTING OF ICD & CRT
  13. 13.  after a first unsuccessful shock in case of concurrent termination of the episode of VT, SVT or device interpreted tachycardia, an inappropriate second shock may be delivered.  This second shock is so-called “committed”, meaning that it is delivered without further pre-evaluation, for reasons of safety to prevent under-detection and under-treatment of arrhythmias.  Commitment also starts when the first therapy of an episode has been diverted but the arrhythmia restarts before the episode has ended.  It is also important to have a thorough awareness of discrimination algorithms and their flaws to troubleshoot various inappropriate shocks in SVT TROUBLE SHOOTING OF ICD & CRT
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  18. 18. Medtronic PR Logic
  19. 19. StJude Medical ICD
  20. 20. BostonScientific Rhythm ID algorithm
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  23. 23. NONTACHYARRHYTHMIAS  Oversensing can be classified by electrogram morphology, temporal pattern (cyclic versus noncyclic), source type (physiological versus nonphysiological), and source location (intracardiac versus extracardiac)  temporal pattern of oversensed signals as varying consistently with the ventricular cycle (cyclic) or independent of the ventricular cycle (noncyclic). TROUBLE SHOOTING OF ICD & CRT
  24. 24. Ventricular oversensing in implantable cardioverter defibrillators (ICDs): classification and common causes. *Oversensing atrial electrograms in atrial fibrillation (eg, ventricular lead dislodged to atrium) also causes noncyclic oversensing. Charles D. Swerdlow et al. Circ Arrhythm Electrophysiol. 2014;7:1237-1261 Copyright © American Heart Association, Inc. All rights reserved.
  25. 25. P-Wave Oversensing  P waves may be oversensed if the proximal ventricular sensing electrode is close to the tricuspid valve.  Recording an atrial electrogram facilitates recognition of P-wave oversensing.  Ventricular oversensing of atrial electrograms in AF may result in multiple oversensed physiological signals for each true cardiac cycle, producing an interval plot with short, irregular intervals, characteristic of nonphysiological oversensing.  P-wave oversensing is rare in adults because the ventricular sensing bipole is usually far from the atrium. Thus, early after implant, P-wave oversensing usually indicates RV lead dislodgement to a position closer the atrium. TROUBLE SHOOTING OF ICD & CRT
  26. 26.  However, P-wave oversensing may occur in children with small right ventricles and in adults with integrated bipolar sensing.  first approach to clinically significant P-wave oversensing is to reduce the programmed ventricular sensitivity.  If this is unsuccessful or sensing of VF is not reliable at the reduced sensitivity, the ventricular lead should be revised.  As a temporary measure, P-wave oversensing in sinus rhythm may be mitigated by forced atrial pacing, by introducing or increasing ventricular blanking after each atrial event. TROUBLE SHOOTING OF ICD & CRT
  27. 27. Spectrum of ventricular P-wave oversensing. Copyright © American Heart Association, Inc. All rights reserved. decreasing sensitivity increasing the ventricular blanking period after atrial pacing.
  28. 28. R-Wave Double Counting  R-wave double counting occurs if the duration of the sensed electrogram exceeds the short ventricular blanking period in ICDs.  Consistent double counting results in an alternation of ventricular cycle lengths.  The expected sensed event early in the R wave is followed by a second, event as soon as the ventricular blanking period ends, which always corresponds to an interval in the VF zone.  The duration of the device-detected interval that begins with the second event approximates the difference between the spontaneous ventricular cycle length and ICD’s blanking period.  This produces a characteristic railroad track pattern on a plot of stored of ventricular intervals. TROUBLE SHOOTING OF ICD & CRT
  29. 29. Railroad track patterns on plot of stored ventricular intervals. Copyright © American Heart Association, Inc. All rights reserved. A, T-wave oversensing. B, R-wave double counting.
  30. 30.  R-wave double counting often results from local ventricular conduction delay.  In conducted rhythm, it is most common when ICDs with short ventricular blanking periods ≤120 ms are connected to integrated bipolar leads.  If the blanking period is programmable, it may be increased when using these generators with integrated bipolar sensing.  R-wave double counting may be precipitated by reversible conduction block caused by hyperkalemia or sodium channel blocking antiarrhythmic drugs.  The primary troubleshooting intervention is to increase the ventricular blanking period TROUBLE SHOOTING OF ICD & CRT
  31. 31. R-Wave Double Counting TROUBLE SHOOTING OF ICD & CRT
  32. 32. R-Wave Double Counting TROUBLE SHOOTING OF ICD & CRT
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  34. 34. R-wave double counting. Charles D. Swerdlow et al. Circ Arrhythm Electrophysiol. 2014;7:1237-1261 Copyright © American Heart Association, Inc. All rights reserved.
  35. 35. T-Wave Oversensing  T-wave oversensing presents as alternating morphologies of device-detected sensing electrograms: Higher frequency R waves alternate with the lower frequency T waves.  hallmark of T-wave oversensing is alternation of electrogram signal frequency content, not device-measured cycle length, which is easier to appreciate on wideband electrograms than narrowband electrograms.  A simultaneous shock electrogram confirms that alternate low-frequency electrograms represent T waves. TROUBLE SHOOTING OF ICD & CRT
  36. 36.  T-wave oversensing was a major problem for early ICDs: oversensing that could not be treated by reprogramming accounted for 13% of lead revisions in a multicenter study conducted from 1993 to 2004.  emerged as the leading cause of oversensing for the subcutaneous ICD.  To reduce T-wave oversensing associated with a fixed-low sensing threshold while retaining sensitivity for VF, ICDs adjust sensitivity dynamically to become progressively more sensitive after each sensed or paced event  automatic control of sensitivity affect the trade-off between preventing T- wave oversensing and minimizing VF undersensing TROUBLE SHOOTING OF ICD & CRT
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  40. 40.  T-wave oversensing with large R waves is caused by an absolute increase in T- wave amplitude.  Clinical correlates include pediatric patients, hypertrophic cardiomyopathy, long QT syndrome, short QT syndrome, hyperkalemia,and, rarely, other drug and metabolic abnormalities.  with small R waves, resolution usually requires an alternative approach  small R waves, oversensed T waves usually have normal amplitude, such as in Brugada Syndrome or advanced myocardial disease.  The root cause relates to a fundamental limitation of automatically adjusted sensitivity, which links the initial value of sensitivity to the amplitude of the preceding R wave. TROUBLE SHOOTING OF ICD & CRT
  41. 41. Ventricular dynamic sensing in St JudeMedical ICD & programming to prevent T-wave oversensing.
  42. 42. T-Wave Oversensing: Prevention and Remediation  Minimum Sensing Threshold  Dynamic Sensitivity  Filtering and Rectification  Algorithmic Rejection of T Waves  New Sensing Lead TROUBLE SHOOTING OF ICD & CRT
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  44. 44. Features to minimize T-wave oversensing. Copyright © American Heart Association, Inc. All rights reserved.TROUBLE SHOOTING OF ICD & CRT applied during initial detection and redetection, but not during pacing.
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  46. 46. Oversensing Physiological Extracardiac Signals: Myopotentials  Diaphragmatic Myopotentials  These low-amplitude, high-frequency signals are more prominent on the sensing electrogram than the shock electrogram because the sensing bipole is closer to the source.  Their amplitude varies with respiration, but not the cardiac cycle .  Oversensing is most common with integrated bipolar sensing at the RV apex and rare with dedicated bipolar sensing or leads in the RV outflow tract.  it commonly occurs in pacemaker-dependent patients, in whom inhibition of pacing maintains high ventricular sensitivity, resulting in persistent oversensing and inappropriate detection of VF  Oversensing may be corrected by reducing ventricular sensitivity if VF sensing is reliable. In pacemaker-dependent patients, pacing at a faster rate may prevent oversensing by not allowing sensitivity to reach its minimum value  The nonprogrammable Boston Scientific noise rejection algorithm operates continuously and may reduce oversensing. Occasionally, correction requires inserting a new sensing or defibrillation lead away from the diaphragm. TROUBLE SHOOTING OF ICD & CRT
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  48. 48. Pectoral Myopotentials  These high-frequency, variable amplitude signals are prominent on electrograms that include the ICD can, including shock electrograms and leadless ECG.  They may be reproduced by pectoral muscle exercise. ICDs do not use these signals as primary sensing channels, pectoral myopotentials do not cause oversensing if the lead is intact.  they may cause misclassification of exercise-induced sinus tachycardia as VT because algorithms that discriminate VT from SVT based on ventricular electrogram morphology use the RV coil-can vector as the default signal .  The diagnosis may be confirmed by monitoring the real-time sensing electrogram during pectoral muscle exercise.  Oversensing of pectoral myopotentials on dedicated bipolar electrograms typically indicates an in-pocket insulation breach. TROUBLE SHOOTING OF ICD & CRT
  49. 49. Pectoral Myopotentials TROUBLE SHOOTING OF ICD & CRT
  50. 50. Oversensing Nonphysiological Signals: Electromagnetic Interference  it typically presents as rapid, noncyclic signals on multiple channels; and the diagnosis can often be confirmed by a history of exposure at the time of the stored episode.  EMI may not be recorded on every channel because of differences in electrode surface area, interelectrode distance, antenna spatial orientation, amplifier sensitivity, and bandpass filters.  External EMI usually has lower amplitude on channels recorded from small, closely spaced electrodes than on those recorded from widely spaced electrodes or those that include a large defibrillation electrode. TROUBLE SHOOTING OF ICD & CRT
  51. 51. Electromagnetic interference (EMI). Copyright © American Heart Association, Inc. All rights reserved.
  52. 52. Oversensing in the Diagnosis of ICD Lead Failure  Of all the causes of oversensing, early diagnosis may be most important in lead failure, which commonly presents with repetitive inappropriate shocks and less commonly causes loss of bradycardia pacing or failure to deliver therapeutic shocks.  Pace-sense malfunctions, either conductor fractures or insulation breaches, account for the majority of clinically diagnosed lead failures TROUBLE SHOOTING OF ICD & CRT
  53. 53. Oversensed Signals in Pace-Sense Conductor Fractures and Connection Problems  conductor fractures cause nonphysiological signals often are referred to as make-break potentials because indistinguishable signals can be generated by connecting and disconnecting cables from the sensing circuit.  typical signal has 6 characteristics, of which the first 3 are almost always present : (1) signals are intermittent and have a high dominant frequency. (2) They display ≥1 types of variability including amplitude, morphology, or frequency. (3) In dedicated bipolar leads, they are not recorded on the shock channel. (4) Usually, at least some signals are not cyclic. (5) Often, some intervals are nonphysiological, shorter than typical physiological intervals. (6) Signal amplitude may exceed the range of the sensing amplifier and thus appear truncated. TROUBLE SHOOTING OF ICD & CRT
  54. 54. Nonphysiological signals of pace-sense conductor fracture and lead-header connection problem. Charles D. Swerdlow et al. Circ Arrhythm Electrophysiol. 2014;7:1237-1261 Copyright © American Heart Association, Inc. All rights reserved.
  55. 55. Oversensed Signals in Insulation Breaches  Unlike conductor fractures, insulation breaches themselves do not generate abnormal signals. Instead, oversensing occurs because signals enter the intact conductor at the insulation breach. Thus, electrogram patterns vary, reflecting the physiological or nonphysiological source signal.  Intermittent, high-amplitude pectoral myopotentials on the sensing channel suggest in-pocket, outside-in abrasion .  Inside-out insulation breaches may cause mechanical interactions between the 2 shock components, the 2 pace-sense components (ring cable and central helix), or 1 pace-sense and 1 shock component. The latter 2 may present as oversensing.  Inside-out breaches of Riata leads often have characteristic spikes on the sensing channel or both sensing and shock channels that may represent such mechanical interactions TROUBLE SHOOTING OF ICD & CRT
  56. 56. Electrogram (EGM) spikes and impedance trends in insulation breaches. Charles D. Swerdlow et al. Circ Arrhythm Electrophysiol. 2014;7:1237-1261 Copyright © American Heart Association, Inc. All rights reserved.TROUBLE SHOOTING OF ICD & CRT
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  58. 58. UNSUCCESSFUL SHOCK  SVT MUST BE RULED OUT  SUBSTRATE RE-EVALUATION-ISCHEMIA,SCAR  DRUG THERAPY  REASSES DFT (DEFIB THRESHOLD) IN LAB TROUBLE SHOOTING OF ICD & CRT
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  63. 63.  If no episodes of tachyarrhythmia or bradyarrhythmia are stored in device memory and if the patient is not pacemaker dependent, cardiac arrhythmia probably did not cause the syncopal episode.  In pacemaker-dependent patients, special attention should be paid to the exclusion of oversensing (with pacing inhibition) as the cause of syncope.  If no oversensing is manifest at rest or on the stored EGM, such physical maneuvers as deep breathing and upper-extremity isometric exercises should be tried in an effort to recreate oversensing, before ruling that out as the cause of syncope.  VT with a cycle length below the cut-off rate, unless ongoing during clinical evaluation, is less easily detectable since the detection criteria have not been met and no episodes will be stored. However, clues hidden in the cardiac flash back (Medtronic) or the Trending (Boston Scientific) help to reveal the arrhythmia.  antiarrhythmic drugs or ablation may be reasonable alternatives. TROUBLE SHOOTING OF ICD & CRT
  64. 64. Palpitations  Although not emergency , a frequent complaint at regular ICD follow-up.  interrogation - underlying cause since it may reveal the occurrence of irregular or fast atrial arrhythmias, PVCs or non-sustained VTs.  Sustained VTs with a cycle length below the cut-off rate are especially difficult to diagnose when the VT is not ongoing during follow-up.  If history is pointing in this direction, the monitor zone can be adjusted to store these arrhythmias.  Decreasing the lower rate of the pacemaker or lowering the beta-blocker dosage may resolve these complaints.  If a careful analysis of the stored EGMs does not help to answer the question, Holter monitor or an event monitor—has to be used. TROUBLE SHOOTING OF ICD & CRT
  65. 65. Alerts  Most ICDs have alerts that notify the patient of undesired settings or electrical events of the ICD and/or leads.  The alerts produce audible signals (Medtronic, Boston Scientific) or a vibrational sensation (St Jude).  Alerts are repetitive, discontinuous signals that can be programmed to a specified time.  Most alerts are programmable (on/off), except “system alerts” that convey debilitated functioning with respect to proper treatment of tachycardia. TROUBLE SHOOTING OF ICD & CRT
  66. 66. goals of ICD programming  -detect high rate NSVT, as they are predictive of ICD discharge for life- threatening arrhythmias and all-cause mortality  -avoid unnecessary treatment of NSVT by delaying ICD intervention as tolerated by the patient  -discriminate SVTs  -terminate sustained VT and VF while minimizing shock therapy  -monitor AF, SVTs, and slow VTs for stroke prevention management, ablative and/or drug therapy  -provide alert on technical (lead integrity and device) and patient-related (atrial fibrillation, heart failure) medical issues TROUBLE SHOOTING OF ICD & CRT
  67. 67. ICD programming  comprehensive process based on the patient's clinical history and encompasses:  -Arrhythmia detection: Zones setting Detection duration of each programmed zone SVT discrimination  -Termination of ventricular arrhythmias  -Choice of the device type  -Monitor zone programming  -Device and clinical alerts TROUBLE SHOOTING OF ICD & CRT
  68. 68. Overview of detection& treatment of ventricular arrhythmia by ICD
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  72. 72. CRT OPTIMISATION -Aortic VTI Method  Objective:  Identify the AV Delay that yields the maximum cardiac output as determined by an aortic VTI measurement  Procedure:  Obtain continuous wave Doppler echo of aortic valve outflow to obtain VTI measurement  Record VTI values over a range of programmed AV Delays  Program the AV Delay value that yields the maximum aortic VTI TIPS & TRICKS OF CRT
  73. 73. TIPS & TRICKS OF CRT
  74. 74. Iterative Method  Objective:  Identify the AV Delay that maximizes LV filling using mitral velocity echocardiographic measurements1  Procedure  Obtain transmitral Doppler echo at a “long” programmed AV Delay during ventricular pacing  Shorten the programmed AV Delay by 10-20 ms until the echo Doppler A-wave becomes truncated (A wave is atrial contraction)  Lengthen the programmed AV Delay back to the value where there is no A-wave cutoff. This timing should enable ventricular contraction to occur just at the end of atrial systole TIPS & TRICKS OF CRT
  75. 75.  to maximize DFT (i.e. separation of the E- and A- waves).  to allow complete end-diastolic filling(marked by the end of the A- wave)before the onset of LV contraction. TIPS & TRICKS OF CRT
  76. 76. Diastolic mitral regurgitation (Ishikawa) method  Aims to minimize diastolic MR.  optimal AV delay = long AV delay - duration of diastolic MRTIPS & TRICKS OF CRT
  77. 77. Mitral inflow velocity time integral  VTI is calculated representing the stroke volume of mitral inflow as a surrogate of LV filling volume.  The AV delay with the largest VTI is considered the optimal setting.  good correlation with optimization by LV dP/dtmax (r=0.96) in a small study of 30 patients TIPS & TRICKS OF CRT
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