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Download CRT Troubleshooting HRUK accreditation course October 2010
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CRT Troubleshooting HRUK Certificate of Accreditation Course Devices Karen Lascelles Senior Chief Cardiac Physiologist Royal Brompton Hospital Pacing Clinic Programmers Amazingly skilled physiologists ECG machine Resus trolley Manufacturers info Magnets Database Patient files ICD Clinic CRT CRT Aims >90% biventricular pacing – resynchronise ventricular activity, maximise pumping efficiency and improve CO Sinus tracking to allow greater HRV Optimisation of AV delay long enough to allow adequate filling time without allowing fusion beats short enough to pace BiV and reduce mitral regurgitation without decreasing atrial kick Ensure appropriate LV diastolic filling V-V optimisation controversial LV lead LV implant Coronary sinus access Mid posterolateral position Appropriate venous access Lead stability CRT-P CRT-D Unusual implant Clinic Issues 1) Failure of pacing / sensing / impedance etc 2) Identification of lead positions 3) Confirmation of LV capture - morphology 4) Diaphragmatic twitching 5) Anodal capture 6) Confirmation of biventricular pacing 7) Heart failure assessment 8) No change in symptoms 2) Identification of lead positions Physical connections DDD ppm used as biV device Shortest AV delay possible (30ms) Check which port corresponds to RV / LV Check whether RV lead is apical or septal Biventricular ppm with apex + septal leads Example November 2008 MB 43 yrs female Pacemaker implant in Brazil Recently moved to UK from Italy Referred from heart failure consultant Initial EGM trace Never Assume!! Atrial threshold ? A ring -case Pacing AAI 3) Confirmation of LV capture Start with Lead 3 RV pacing - LBBB pattern LV pacing – ‘outflow’ pattern – inferior axis Compare with intrinsic and with biV pacing 12 Lead ECG 12 lead RV pacing 12 lead LV pacing 12 Lead RV pacing QRS duration 212ms 12 Lead LV Pacing QRS duration 208ms BiV 12 lead QRS duration 176ms Pacing Morphology LV Lead 3 RV Lead 3 Biventricular Pacing BiV Pacing Intrinsic LV Capture Lead 3 4) Diaphragmatic Pacing ‘Thumping’ in left abdomen Most commonly caused by LV lead Test all leads separately to be sure Change LV pacing configuration and recheck thresholds (electrically ‘moving’ the LV lead) Do not need x 2 voltage in LV Reproduce symptoms if possible Manoevre patient to check ? Reposition? LV Configurations 5) Anodal Capture Capture of RV during LV pacing Using RV coil or ring as anode (positive) More common at high output Identified by morphology change during threshold testing Pace RV only and LV only to check morphology 12 lead ECG if necessary Anodal capture LV Threshold Lead 3 AEGM RVEGM Markers Output Same LV Threshold Lead 3 End test Lead 3 Anodal Capture LV ring to RV ring Intrinsic BiV far field sensing Lead 3 a A EGM What do I do now? Check all thresholds carefully Assess output which causes RV capture Program LV output between RV & LV Change LV pacing configuration Use most appropriate (reducing output) Turn off LV lead – physician input Reposition ? 5) Confirmation of Biventricular Pacing P wave tracking LV lead is definitely capturing LV without causing anodal capture of RV Appropriate A-V delay to pace both ventricles consistently without obvious fusion or pseudofusion. Rapid rates Failure of biventricular pacing due to rapid intrinsic rate (AF / sinus tachy). Algorithm to allow tracking of rapid V rates (including VEs) Use manufacturers algorithms with care: Sense response BiV Trigger DDT mode RV tracking (MD) (BSc) (SJM) (Btk) Rapid AF conduction rate LECG Can – RV ring AEGM Shock EGM Lead 2 BiV pacing Lead 1 A EGM Can – RV ring Shock EGM Dot Plot Biventricular response AEGM Can RV ring Fusion During intact PR conduction AV delay too long to ensure complete biventricular capture Allows fusion or pseudofusion Shorten A-V delay (<130ms) Check ECG HF Assessment Pt signs and symptoms (SOB, dyspnoea, ankle oedema) Increase in heart rate – especially nocturnal Heart rate variability reduced Thoracic impedance decreased Assess manufacturers diagnostics HF Diagnostics % Pacing Av. V Rate Pt. Activity HRV HF Diagnostics Thoracic Impedance No change in patient symptoms Literature up to 30% do not have any symptomatic improvement Small % worse Echo optimisation of A-V and/or V-V interval ? Effect of rate responsive A-V or fusion during higher heart rates Heart failure team involvement Optimal medication Case Study TS Male 77yrs Out of hospital arrest AF, EF 28%, NYHA 2 No significant coronary disease BiV ICD implanted 09/10 One day post implant Lead 3 A Bipolar Resting rhythm strip X ray Intrinsic Rhythm LV threshold RV threshold Any Questions ? Good Luck!
