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BLOCK HF trial
The document summarizes several studies on cardiac resynchronization therapy (CRT) for heart failure. The Block HF trial found that CRT was superior to right ventricular pacing alone in reducing death and heart failure-related events in patients with heart failure, left ventricular dysfunction, and AV block. Subsequent trials like COMPANION, CARE-HF, REVERSE, and MADIT-CRT also demonstrated benefits of CRT over medical therapy alone in improving outcomes like mortality, hospitalizations, quality of life and left ventricular function. Updated guidelines have expanded the use of CRT to patients in NYHA class I/II with left bundle branch block and QRS duration over 150ms.
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BLOCK HF trial
- 1. The Block HFstudy JACC May 2016 Dr Joura Vishal
- 2. Introduction • Heart failure: end stage of various cardiac conditions • Refractory heart failure : symptoms at rest inspite of diet , fluid modifications and Optimal medical therapy ( OMT ) • Affects 2.5 % in United states and european countries 2.5 to 5 million in India
- 3. Introduction • Systolic heartfailure may have - intraventricular dyssynchrony - interventricular dyssynchrony - atriventricular dysnchrony These patients are at high risk of refractory heart failure and suden cardiac death Baldasseroni et al Am Heart J 2002
- 5. Introduction Cardiac resynchronization therapy •minimises regional left ventricular delay • Reduces Mitral regurgitation • Normalises neurohormonal factors Thus altering the natural history of disease Mc Alister FA et al JAMA 2007
- 6. Introduction Biventricular pacing isa/w - improved QOL - increased functional capacity - reducing hospitalization - Improved survival
- 7. The Block HFtrial RV pacing lead to worse clinic outcomes compared to low rate ventricular pacing in patients with pacemakers and ICD who have intact AV conduction In AV block pacing is required all the time
- 8. Hypothesis In patients with AVblock , LVEF < 50% , NYHA class I , NYHA II Biventricular pacing would be superior to RV pacing with respect to • combined end point of death • heart failure related urgent care • adverse LV remodeling manifested by a > 15 % LVESV index
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- 11. Methods • Prospective • Multicenter( 58 sites in United States & 2 in Canada ) • Randomized • Double blind
- 12. Methods • 918 patientswere enrolled from Dec 2003 till Nov 2011 • 691 randomized • Follow up average 37 months Statistical analysis : Bayesian statistical method was used with pre specified metric of benefit being : posterior probability > 0.95
- 14. Methods Eligibility criteria • ClassI / IIa indication for pacing • NYHA I – NYHA III heart failure • LVEF less than 50%
- 15. Methods Exclusion criteria • Previousreceipt of CRT • Unstable angina • Acute MI • PCI / CABG in last 30 days • Valvular disease with indication for surgery / repair
- 16. Methods • Implanted pacemakerwith or without ICD with biventricular pacing capability • RV pacing for 30 -60days while OMT was given • In patients without atrial arrhythmias atrial lead was also implanted for atrial synchronized RV or biventricular pacing
- 19. Methods • Echocardiographic examinationwas done at baseline then at 6 , 12, 18 and 24 months Prespecified outcomes: • Packer clinical composite score • QOL • NYHA functional class
- 20. Packer composite clinical score Worsened •Died • Experienced a hospitalization • Worsening of NYHA class Improved Improvement in NYHA class Reduced symptoms Unchanged : none of the above criteria met
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- 23. NYHA class atbaseline
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- 25. NYHA functional status inCrossovers
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- 30. Miracle trial • 453patients • Moderate to severely symptomatic • LVEF <35% • QRS >130ms Assessed for NYHA class ; QOL ; 6min walk distance CRT arm versus no CRT with OMT
- 31. Miracle trial :results Significant improvement in • 6 minute walk distance • QOL • Time on treadmill • Ejection fraction • Required fewer hospitalization / iv medications
- 32. Miracle trial Effects similarto those seen with beta blockers in heart failure were seen in this trial but these effects were seen with CRT who were already on beta blockers
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- 38. CARE HF trial •82 European centers • Jan 2001 to march 2003 • non blinded trial • CRT versus OMT Eligible patients ( 404 to CRT ; 409 to OMT ) • NYHA III –IV on OMT • LVEF <35% • LVEDD at least 30mm • QRS >120ms
- 40. Kaplan Meir estimateof primary end outcome
- 41. Kaplan Meir estimateof primary secondary outcome
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- 43. Reverse Trial • 610patients • NYHA class I / II • QRS >120ms • LVEF < 40% Received CRT +/- D
- 44. Reverse Trial • Clinicalcomposite score • LV systolic volume index Results : Significant improvement in LV systolic index Fewer hospitalization
- 45. Reverse Trial Conclusion : CRTreduces the hospitalization in HF patients and improves ventricular structure and function in NYHA class I and II with ventricular dyssynchrony
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- 49. MADIT CRT trial Conclusion CRTD versus ICD alone • Reduced heart failure events • Females benefit more than males • QRS >150 benefit more • Patients with LBBB show a significant reduction in VT /VF and death compared to non LBBB
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- 55. Updated CRT guidelines •Limitation of class I indication to QRS >150ms • Limitation of class I indication to LBBB • Expansion of class I indication to NYHA II and with LBBB with QRS >150ms • Addition of class IIb recommendation who have - LVEF <30% - Ischemic HF - Sinus rhythm - LBBB with QRS > 150 ms - NYHA I