Cardiac resynchronization therapy

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Today, in addition to measurement of left ventricular ejection fraction, the simple 12-lead surface ECG remains the only evidence-based means of identifying patients who may obtain the substantial benefits of CRT

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Cardiac resynchronization therapy

  1. 1. OPTIMIZING CARDIAC RESYNCHRONIZATION THERAPY FOR CONGESTIVE HEART FAILURE Only for systolic heart failure Dr Ramachandra ECG — Still the Best for Selecting Patients for CRT Clyde W. Yancy, M.D., and John J.V. McMurray, M.D.
  2. 2. CRT APPEARS DEADLY IN SHORT-QRS PATIENTS
  3. 3. CRT FOR NARROW QRS WITH LV SYSTOLIC DYSFUNCTION  "This is the final nail in the coffin for CRT in patients with only slightly-prolonged QRS," commented Dr. Douglas P. Zipes, a professor and electrophysiologist at Indiana University in Indianapolis.
  4. 4. PERSPECTIVE  Advanced systolic heart failure  Mechanical dyssynchrony positive  CRT-P/D effective  improving symptoms and reducing mortality.  several recognized approaches to optimize  Imaging modalities can assist with identifying the myocardium with the latest mechanical activation for targeted left ventricular lead implantation.  Device programming can be tailored to maximize biventricular pacing, and thereby is its benefit.  Cardiac imaging has shown that atrioventricular and interventricular intervals can be adjusted to further reduce dyssynchrony.
  5. 5. ELECTRO/MECHANICAL DYSCHRONY IN ADVANCE SYSTOLIC HEART FAILURE. Electrical dyschrony(12-ECG) Mechanical dyschrony(Echocardiogragh) 1D-AV block=AV delay E ,A not keep harmony ,also with R of ECG LBBB=VV conduction delay only in 25% of patients with systolic dysfunction have QRS duration that exceeds 120 ms Paradoxical IVS
  6. 6. MONITORING IMPROVEMENT  ECG-electrical dyssynchrony improvement  ECHO-mechanical dyssynchrony improvement  NYHA CLASS  6-Minute walk  Quality-of-life score  Duration of survival 70-80% response to CRT
  7. 7. LEAD LOCATION FOR CRT OPTIMIZATION  Positioning the LV lead outside the site of latest mechanical activation may be associated with suboptimal response to CRT and worse long-term outcome  left side of the chest is preferred for 2 reasons 1. LSCV-continuous route to access the CS, Rt- challenging/ angulated 2.Defibrillation threshold is less on left  Leads placed in the RA/RV/lateral wall of the LV through the coronary sinus
  8. 8. LEAD LOCATION....CONTD  RV lead first, as baseline LBBB at risk  LV lead next, is challenging one  RA lead is last(even in Afib)  RV lead-no preferential location  LV lead-lateral/posterior-lateral wall of the LV via CS/epicardial= goal of pacing from the most mechanically delayed portion on the LV
  9. 9. ECHO ASSESSMENT OF DYSSYNCHRONY AND CRT RESPONSE  Echocardiography parameters can predict/decide which patient need CRT but helps in monitoring the patients with CRT  SPWMD >130msec is a very good forecaster(Pitzalis MV)  CONTACT-CD denies role of SPWMD  PROSPECTUS-Tissue Doppler is usuful.
  10. 10. DEVICE PROGRAMMING TO OPTIMIZE TIMING  Most studies point to a benefit in adjusting the AV and VV timing.  Variability on the best approach to make these adjustments  how often it should be done?
  11. 11. AV OPTIMIZATION  AV optimization is must after CRT device implant, particularly if the post-CRT implant Doppler echo of the mitral inflow suggests suboptimal diastolic filling patterns  Long A-V interval, Doppler echo will display fused E and A waves with evidence of mitral regurgitation during diastole. Additionally, a prolonged AV delay allows the ventricle to initiate its own beat before receiving a pacing impulse  Short AV interval have a truncated A wave resulting in a loss of the atrial kick, resulting in reduced contribution from the atria and reduced ventricular filling time  Optimal AV timing can be identified with aortic systole that begins at the end of A  Aortic velocity time integral (VTI), which is a surrogate for cardiac output, can be used for AV optimization. The optimal AV delay is determined by adjusting the AV delay until the largest aortic VTI is achieved.
  12. 12. SIMPLIFIED AV DELAY SCREENING USING MITRAL INFLOW DOPPLER VELOCITIES
  13. 13. OPTIMIZING AV DELAY USING VTI
  14. 14. VV OPTIMIZATION  2D ECHO:A delayed interval of 40-50 ms has been accepted as being indicative of VV dyssynchrony. MIRACLE trial, the measurement of VV mechanical delay was reduced by approximately 19% after CRT.Yu et al reported normalization in dyssynchrony in patients who previously had significant mechanical delay in the lateral wall of the LV and RV  3D ECHO  Dp/dt(echo)  Exercise benefit
  15. 15. INTERVENTRICULAR OPTIMIZATION USING AORTIC VELOCITY TIME INTEGRAL (VTI).
  16. 16. HOW OFTEN TO OPTIMIZE CRT DEVICES?  Optimal follow-up/long-term programming for CRT devices is uncertain  Frequent monitoring/adjustment to maintain optimal AV and VV timings  FREEDOM -will determine whether frequent optimization of CRT ,using a new device-based algorithm, is associated with better clinical outcomes than current standard of care
  17. 17. TAKE HOME  CRT address systolic heart failure  Rectify mechanical dyssynchrony  improving symptoms and reducing mortality.  There are now several recognized approaches to optimize CRT.  Imaging modalities can assist with identifying the myocardium with latest mechanical activation for targeted LV lead implantation.  Device programming can be tailored to maximize biventricular pacing and thereby its benefit.  Cardiac imaging has shown that AV and VV intervals can be adjusted to further reduce dyssynchrony. Optimization of CRT devices continues to be an area of active research
  18. 18. A RARE MOST BEAUTY AND FRAGRANCE ON THIS EARTH “BRAMAKAMAL

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