Cardiac Resynchronization therapy.pptx

Cardiac Resynchronization Therapy

1. Cardiac Resynchronization Therapy Dr Seebat masrur D-card resident Cardiology department szmch

2. CRT CRT is treatment for heart failure, appropriate in the setting of sufficiently depressed LVEF and electrically dyssynchronous ventricular function It is the last device option to treat heart failure before LVAD, heart transplant!

3. What is Dyssynchrony ? Dyssynchrony refers to impaired mechanical coordination due to impaired electrical activation of heart muscle. Electrical dyssynchrony identified by prolonged QRS duration on ECG. QRS prolongation typically due to conduction system disease, such as bundle branch block. Chronic pacing-induced conduction delays due to high RV(single chamber) pacing burden.

4. Types of Dyssynchrony AV Dyssynchrony Interventricular Dyssynchrony Intraventricular Dyssynchrony Other Types Mechanical Dyssynchrony Electrical Dyssynchrony

5. Cardiac Resynchronization Therapy All patient with heart failure need optimal pharmacological therapy and lifestyle modifications. But in a small subset, there is a definite role for devices. Intraventricular dyssynchrony in the presence of severe left ventricular dysfunction is an important indication for cardiac resynchronization therapy. Delay between the contractions of the septum and the lateral left ventricular wall causes reduced left ventricular stroke volume.

6. Cardiac Resynchronization Therapy The important surrogate of ventricular dyssnchrony is an increased QRS duration. In CRT, septum and lateral left ventricular wall contracts simultaneously producing improvement in the left ventricular stroke volume. CRT improves the symptomatic status and survival of the heart failure patients with left ventricular dyssynchrony . But still there is a 30% non-responder rate of patients who do not respond to CRT.

7. Cardiac Resynchronization Therapy QRS duration of 150 ms or more with LBBB pattern in a person with refractory heart failure will be a strong indication for cardiac resynchronization therapy. It is often associated with mechanical dyssynchrony and wasted systolic effort of the left ventricle. CRT produces a narrowing of the QRS complexes as the right ventricle and posterolateral left ventricle are paced in synchrony, to produce a better left ventricular output. CRT system may include ICD protection(CRT-D), or provide only pacing therapy(CRT-P)

8. CRT System-Three leads

9. CRT implant Objectives- lead Placement

10. CRT advantages with Quadripolar LV lead REF-https://www.ahajournals.org/doi/10.1161/JAHA.117.007026 Better CRT Lead Stability Phrenic Nerve capture Lowest threshold CRT  using  QUAD , programmed to biventricular pacing with single‐site  LV  pacing, is associated with a lower total mortality, cardiac mortality, and  HF  hospitalization.

11. Patient selection criteria

12. CRT guidelines for pt in AF

13. Recommendation for upgrade from right ventricular pacing to cardiac resynchronization therapy

14. Selection criteria for CRT

15. Who Qualifies for CRT

16. Who responds to CRT? Overall response rate 70% Significant dyssynchrony Minimal Lateral LV scar Adequate CS anatomy

17. Sliding Scale of Efficacy

18. Predictors of CRT Response LBBB is best marker QRS duration is critical NICM>ICM Women>Men

19. CRT in heart failure with narrow QRS complex In patient with systolic HF and a QRS duration of less than 130 msec, CRT does not reduce the rate of death or hospitalization for heart failure and may increase mortality.

20. Echocardiographic parameters M-mode : Septal posterior wall motion delay at papillary muscle level in parasternal short axis view , 130 ms has a sensitivity of 24% specificity of 66%. Interventricular mechanical delay : Difference between LV and RV pre-ejection period. Beginning of QRS chamber view and beginning of QRS to beginning of RV ejection in short axis view; difference > 40 ms is significant. Tissue Doppler Imaging : Septal to lateral wall delay in time to peak velocity > 60ms is suggestive of dyssynchrony .

21. PROSPECT TRIAL Conclusion Echo guided CRT patient selection has no prospect

22. Procedure

23. Reverse Remodeling with CRT reduces life threatening Ventricular arrhythmias There have been some reports of whether the altered sequence of ventricular depolarization with CRT can be arrhythmogenic.

24. CRT reduces life threatening ventricular arrhythmias They grouped the subjects into three- those with 25% or more reduction in LV end systolic volume at one year compared with baseline, those with less than 25% reductions and those who received only ICD and not CRT-D. The first group was the CRT responders and the second one CRT non-responders. The highest rates of ventricular tachyarrhythmias was highest in the nonresponder (28%) & lowest in the responders(12%)

25. CRT reduces life threatening ventricular arrhythmias The ICD only group had an intermediate value of 21% This was for the cumulation probability of first ventricular tachyarrhythmias at two years after the initial assessment

26. CRT reduces life threatening ventricular arrhythmias Multivariate analysis showed a 55% risk reduction between CRT responders and ICD only patients, while the difference was not significant between non responders and ICD only patients. It concluded that reverse remodeling with CRT is associated with significant ventricular arrhythmias

27. ECG in CRT Leads I, II & III are most useful in deciding whether it is RV, LV or biventricular pacing. Since the pattern varies from individual to individual, it is good to preserve the tracings of all modes of pacing for future comparison.

28. CXR in CRT

29. Complication Lead related reintervention-dislodgement, malposition, subclavian crush syndrome CIED-related infections, <12 months-Superficial infection, pocket infections, systemic infections CIED-related infections, >12 months-Pocket infections, systemic infections Pneumothorax Hemothorax Brachial plexus injury Cardiac perforation Coronary sinus dissection/perforation Diaphragmatic stimulation Hematoma, Seroma Tricuspid regurgitation Pacemaker syndrome

30. Non responders to CRT About 30% of patients do not respond to CRT. The reasons could be any one of the following; Not every patient with wide QRS has dyssynchrony and vice versa. Leads may be too close to each other to produce synchronous contraction of septum and lateral wall. Scarred region of the ventricular can cause poor capture and synchronization.

31. Non responders to CRT Consistent ventricular capture by spontaneous impulses can also prevent resynchronization. This is more likely to occur in atrial fibrillation with fast ventricular rate.Attempts at AV nodal ablation to counter this problem have been tried.In sinus rhythm, this problem can be reduced by programming a AV delay. Dislodgement of LV lead can also be a cause of poor synchronization.

32. Monitoring Improvement ECG-Electrical dyssynchrony improvement ECHO-Mechanical dyssynchrony improvement NYHA Class 6 mins walk test Quality of life scores

33. CRT benefits Identifying responders Symptoms -Improved exercise tolerance -Reduced SOB -Improved NYHA status Reversed LV remodeling -Improved LVEF, Reduced size, reduced MR Prognosis -Reduced CHF hospitalization Reduced mortality

34. Take Home Message CRT has emerged as an effective therapy in patients with LVD refractory to CHF medications and a wide QRS duration. Major clinical trials have proven significant morbidity and mortality benefits from CRT. The issue of nonresponse to CRT continues to be a major problem. While the response to CRT in patients with a native LBBB or ­RV-paced rhythm is well documented, the response in patients with RBBB or a nonspecific IVCD continues to be debated.

35. Thank you

36. Selection criteria for CRT Severe heart failure NYHA class III or IV. Depressed left ventricular ejection fraction <35% QRS duration 150 ms or more. Most widely used marker of dyssynchrony is surface ECG. But it is not absolute marker as it may not have complete correction with mechanical dyssynchrony . LBBB is associated with dyssynchony of lateral wall compared to the septum. Should be in sinus rhythm for better synchronization and should be on optimal medical therapy.

37. Selection criteria for CRT Those with recent myocardial infarction or have undergone coronary revascularization within 3 months as well as those scheduled for coronary revascularization are excluded. This is in view of the potential for improvement in the left ventricular function in the short term.

38. Take Home Message CRT address systolic heart failure Rectify mechanical dyssynchrony Improve symptoms and reduce mortality

39. CRT implantation- Basic cannulation of coronary sinus Start ventricular to tricuspid valve and withdraw applying counter clockwise torque to stay septally to cannulate the coronary sinus ostium. LAO is lined upon the interventricular septum. The orthogonal view is RAO. A prominent Thebesian valve with ab associated pouch causes the lead to fall into it and causes difficult in cannulating the coronary sinus. Injecting a whiff of dye will help delineate the position of the sheath in the pouch, which causes transient dye stasis.

40. CRT implantation-Inability to advance in coronary sinus In ability to advance in CS could be due to stenosis, valves, subs election, dissection and tortuosity. Vieussen`s valve is an embryonic remnant, seen at the origin of the posterolateral ventricular vein. If there is a prominent valve in the posterolateral vein, we can cannulate the middle cardiac vein and go into a lateral branch of this vein

41. CRT implantation-Inability to advance in coronary sinus CS stenosis can be ballon dilated, but branch vein stenosis is better left alone. Search for other veins which could be used. This will also reduce the dye load in attempted dilation. Dissections can occur due to dye injections and by sheath advancement. In most of the dissection is distal, try using the lateral branch of the middle cardiac vein. Pushing a catheter which is sub selected without recognizing it is one of the reasons for dissection.

42. CRT implantation-Inability to advance in coronary sinus If it is atrial vein subselection , withdraw it If it is ventricular vein subselection , cannulation is over! So try to recognize it with appropriate views

43. CRT implantation-Inability to get lateral veins If it is atrial vein subselection , withdraw it. If it is ventricular vein subselection , cannulation is over. So try to recognize it with appropriate views

44. Need for ICD lead in Left ventricle When there is a mechanical tricuspid valve which you don’t want to cross, an ICD lead may have to be placed in a coronary vein.