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Biventricular Versus Right Ventricular Pacing in Heart Failure Patients With Atrioventricular Block (BLOCK HF) (BLOCK HF)

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
Medtronic Cardiac Rhythm and Heart Failure
ClinicalTrials.gov Identifier:
NCT00267098
First received: December 19, 2005
Last updated: February 20, 2014
Last verified: February 2014
Results First Received: December 18, 2013  
Study Type: Interventional
Study Design: Allocation: Randomized;   Endpoint Classification: Safety/Efficacy Study;   Intervention Model: Parallel Assignment;   Masking: Double Blind (Subject, Outcomes Assessor);   Primary Purpose: Treatment
Conditions: Atrioventricular Block
Heart Diseases
Intervention: Device: Cardiac Resynchronization Therapy (CRT)

  Participant Flow
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Recruitment Details
Key information relevant to the recruitment process for the overall study, such as dates of the recruitment period and locations
No text entered.

Pre-Assignment Details
Significant events and approaches for the overall study following participant enrollment, but prior to group assignment
No text entered.

Reporting Groups
  Description
No Implant Attempt Subjects who did not undergo an implant attempt of a CRT-P or CRT-D device and were not randomized
Unsuccessful Implants Subjects who underwent an implant attempt of a CRT-P or CRT-D device but were not successfully implanted
CRT-P: Biventricular Pacing Arm Subjects who were implanted with a CRT-P device and randomized to receive biventricular pacing
CRT-P: Right Ventricular Pacing Arm Subjects who were implanted with a CRT-P device and randomized to receive right ventricular pacing
CRT-P: Not Randomized Subjects successfully implanted with a CRT-P device who were not randomized
CRT-D: Biventricular Pacing Arm Subjects implanted with a CRT-D device and randomized to receive biventricular pacing
CRT-D: Right Ventricular Pacing Arm Subjects implanted with a CRT-D device and randomized to receive right ventricular pacing.
CRT-D: Not Randomized Subjects successfully implanted with a CRT-D device who were not randomized

Participant Flow:   Overall Study
    No Implant Attempt   Unsuccessful Implants   CRT-P: Biventricular Pacing Arm   CRT-P: Right Ventricular Pacing Arm   CRT-P: Not Randomized   CRT-D: Biventricular Pacing Arm   CRT-D: Right Ventricular Pacing Arm   CRT-D: Not Randomized
STARTED   109   51   243   241   47   106   101   20 
COMPLETED   0   0   149   135   10   66   55   5 
NOT COMPLETED   109   51   94   106   37   40   46   15 
Death                0                0                57                66                14                23                28                9 
Lost to Follow-up                0                0                6                5                2                3                1                1 
Withdrawal by Subject                8                0                24                21                12                9                12                5 
Physician Decision                5                0                7                11                5                4                3                0 
Inclusion/Exclusion Criteria Not Met                96                0                0                0                2                0                0                0 
Unsuccessful Implant Exit Per Protocol                0                51                0                0                0                0                0                0 
Site closure                0                0                0                1                0                1                1                0 
Explanted Medtronic device                0                0                0                1                0                0                0                0 
Non-Medtronic LV Lead Implanted                0                0                0                0                2                0                0                0 
Subject listed for heart transplant                0                0                0                0                0                0                1                0 
Sponsor withdrew subject                0                0                0                1                0                0                0                0 



  Baseline Characteristics
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Population Description
Explanation of how the number of participants for analysis was determined. Includes whether analysis was per protocol, intention to treat, or another method. Also provides relevant details such as imputation technique, as appropriate.
No text entered.

Reporting Groups
  Description
No Implant Attempt Subjects who did not undergo an implant attempt of a CRT-P or CRT-D device and were not randomized
Unsuccessful Implants Subjects who underwent an implant attempt of a CRT-P or CRT-D device but were not successfully implanted
CRT-P: Biventricular Pacing Arm Subjects who were implanted with a CRT-P device and randomized to receive biventricular pacing
CRT-P: Right Ventricular Pacing Arm Subjects who were implanted with a CRT-P device and randomized to receive right ventricular pacing
CRT-P: Not Randomized Subjects successfully implanted with a CRT-P device who were not randomized
CRT-D: Biventricular Pacing Arm Subjects implanted with a CRT-D device and randomized to receive biventricular pacing
CRT-D: Right Ventricular Pacing Arm Subjects implanted with a CRT-D device and randomized to receive right ventricular pacing.
CRT-D: Not Randomized Subjects successfully implanted with a CRT-D device who were not randomized
Total Total of all reporting groups

Baseline Measures
   No Implant Attempt   Unsuccessful Implants   CRT-P: Biventricular Pacing Arm   CRT-P: Right Ventricular Pacing Arm   CRT-P: Not Randomized   CRT-D: Biventricular Pacing Arm   CRT-D: Right Ventricular Pacing Arm   CRT-D: Not Randomized   Total 
Overall Participants Analyzed 
[Units: Participants]
 109   51   243   241   47   106   101   20   918 
Age 
[Units: Years]
Mean (Standard Deviation)
 70.2  (12.6)   71.1  (11.2)   74.4  (10.2)   73.8  (10.8)   79.3  (7.6)   72.0  (9.3)   71.0  (10.0)   74.0  (9.1)   73.2  (10.6) 
Gender 
[Units: Participants]
                 
Female   29   14   62   73   18   19   20   4   239 
Male   80   37   181   168   29   87   81   16   679 
Race/Ethnicity, Customized 
[Units: Participants]
                 
Subject did not offer ethnicity   6   2   6   5   1   4   3   0   27 
African American   10   3   8   10   0   4   4   1   40 
Asian   0   0   0   0   1   0   0   0   1 
Caucasian   91   45   225   224   43   96   90   18   832 
Hispanic   1   0   3   1   2   2   2   1   12 
Native American   0   0   0   1   0   0   0   0   1 
Other   1   1   1   0   0   0   2   0   5 
Region of Enrollment 
[Units: Participants]
                 
United States   109   46   232   231   47   104   98   19   886 
Canada   0   5   11   10   0   2   3   1   32 


  Outcome Measures
  Show All Outcome Measures

1.  Primary:   Mortality, Heart Failure-related Urgent Care Visits, or Significant Increase in Left Ventricular End Systolic Volume Index (LVESVI)   [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]

2.  Secondary:   All-Cause Mortality   [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]
  Hide Outcome Measure 2

Measure Type Secondary
Measure Title All-Cause Mortality
Measure Description

The endpoint is the time to death from any cause. The rate of mortality, as measure by the hazard rate, in each randomization arm will be compared.

This outcome includes all post-randomization deaths, whereas the reporting of the primary outcome excluded primary endpoints (including deaths) that occurred after the subject had missed a study-required echocardiogram (used to determine if the LVESVI primary endpoint was met).

Time Frame Participants were followed for the duration of the study, an average of 39.8 months post-randomization.  
Safety Issue No  

Population Description
Explanation of how the number of participants for analysis was determined. Includes whether analysis was per protocol, intention to treat, or another method. Also provides relevant details such as imputation technique, as appropriate.
Only randomized subjects in both device groups were included in the analysis of this endpoint, as the analysis was restricted to post-randomization data. Subjects in the "No Implant Attempt", "Unsuccessful Implants", "CRT-P: Not Randomized", and "CRT-D: Not Randomized" subgroups were excluded.

Reporting Groups
  Description
Biventricular Pacing Arm Subjects randomized to receive biventricular pacing
Right Ventricular Pacing Arm Subjects randomized to receive right ventricular pacing.

Measured Values
   Biventricular Pacing Arm   Right Ventricular Pacing Arm 
Participants Analyzed 
[Units: Participants]
 349   342 
All-Cause Mortality 
[Units: Participants]
   
Subjects who died   80   94 
Subjects who did not die   269   248 


Statistical Analysis 1 for All-Cause Mortality
Groups [1] All groups
Method [2] Posterior Distribution for HR
P Value [3] 0.865
Hazard Ratio (HR) [4] 0.843
95% Confidence Interval 0.632 to 1.142
[1] Additional details about the analysis, such as null hypothesis and power calculation:
  The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same rate of mortality as corresponding patients who receive right ventricular pacing.
[2] Other relevant method information, such as adjustments or degrees of freedom:
  The posterior distribution is the set of values the BiV to RV hazard ratio for death can take, and its likelihood of taking such values.
[3] Additional information, such as whether or not the p-value is adjusted for multiple comparisons and the a priori threshold for statistical significance:
  BLOCK HF is a Bayesian study; thus p-values were not used. Instead, posterior probabilities, representing the probability that subjects with biventricular pacing have better outcomes, were calculated. A probability ≥ 0.95 was significant.
[4] Other relevant estimation information:
  Because BLOCK HF was a Bayesian study, a 95% credible interval was used in lieu of a 95% confidence interval. This interval reflects the set of values the Hazard Ratio can take with 95% posterior probability.



3.  Secondary:   All-Cause Mortality or Heart Failure-related Hospitalization   [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]

4.  Secondary:   All-Cause Mortality or Significant Increase in Left Ventricular End Systolic Volume Index   [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]

5.  Secondary:   First Heart Failure Hospitalization   [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]

6.  Secondary:   Days Hospitalized for Heart Failure   [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]

7.  Secondary:   Change in New York Heart Association Classification   [ Time Frame: Randomization to 24 Months ]

8.  Secondary:   Change in Heart Failure Stage   [ Time Frame: Randomization to 24 Months ]

9.  Secondary:   Change in Cardiovascular Medications   [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]

10.  Secondary:   Frequency of Adverse Events Post-randomization   [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]

11.  Secondary:   Cardiovascular-related Healthcare Utilizations   [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]

12.  Secondary:   Change in Quality of Life at 6 Months   [ Time Frame: Randomization to 6 Months ]

13.  Secondary:   Change in Quality of Life at 12 Months   [ Time Frame: Randomization to 12 months ]

14.  Secondary:   Change in Quality of Life at 18 Months   [ Time Frame: Randomization to 18 Months ]

15.  Secondary:   Change in Quality of Life at 24 Months   [ Time Frame: Randomization to 24 Months ]

16.  Secondary:   Change in Left Ventricular Ejection Fraction (LVEF) From Randomization to 6 Months   [ Time Frame: Randomization to 6 Months ]

17.  Secondary:   Change in Left Ventricular Ejection Fraction (LVEF) From Randomization to 12 Months   [ Time Frame: Randomization to 12 Months ]

18.  Secondary:   Change in Left Ventricular Ejection Fraction (LVEF) From Randomization to 18 Months   [ Time Frame: Randomization to 18 Months ]

19.  Secondary:   Change in Left Ventricular Ejection Fraction (LVEF) From Randomization to 24 Months   [ Time Frame: Randomization to 24 Months ]

20.  Secondary:   Change in Left Ventricular End Systolic Volume Index (LVESVI) From Randomization to 6 Months   [ Time Frame: Randomization to 6 Months ]

21.  Secondary:   Change in Left Ventricular End Systolic Volume Index (LVESVI) From Randomization to 12 Months   [ Time Frame: Randomization to 12 Months ]

22.  Secondary:   Change in Left Ventricular End Systolic Volume Index (LVESVI) From Randomization to 18 Months   [ Time Frame: Randomization to 18 Months ]

23.  Secondary:   Change in Left Ventricular End Systolic Volume Index (LVESVI) From Randomization to 24 Months   [ Time Frame: Randomization to 24 Months ]

24.  Secondary:   Change in Left Ventricular End Diastolic Volume Index (LVEDVI) From Randomization to 6 Months   [ Time Frame: Randomization to 6 Months ]

25.  Secondary:   Change in Left Ventricular End Diastolic Volume Index (LVEDVI) From Randomization to 12 Months   [ Time Frame: Randomization to 12 Months ]

26.  Secondary:   Change in Left Ventricular End Diastolic Volume Index (LVEDVI) From Randomization to 18 Months   [ Time Frame: Randomization to 18 Months ]

27.  Secondary:   Change in Left Ventricular End Diastolic Volume Index (LVEDVI) From Randomization to 24 Months   [ Time Frame: Randomization to 24 Months ]

28.  Secondary:   Change in Left Ventricular Mass (LV Mass) From Randomization to 6 Months   [ Time Frame: Randomization to 6 Months ]

29.  Secondary:   Change in Left Ventricular Mass (LV Mass) From Randomization to 12 Months   [ Time Frame: Randomization to 12 Months ]

30.  Secondary:   Change in Left Ventricular Mass (LV Mass) From Randomization to 18 Months   [ Time Frame: Randomization to 18 Months ]

31.  Secondary:   Change in Left Ventricular Mass (LV Mass) From Randomization to 24 Months   [ Time Frame: Randomization to 24 Months ]

32.  Secondary:   Change in Left Ventricular End Diastolic Dimension (LVEDD) From Randomization to 6 Months   [ Time Frame: Randomization to 6 Months ]

33.  Secondary:   Change in Left Ventricular End Diastolic Dimension (LVEDD) From Randomization to 12 Months   [ Time Frame: Randomization to 12 Months ]

34.  Secondary:   Change in Left Ventricular End Diastolic Dimension (LVEDD) From Randomization to 18 Months   [ Time Frame: Randomization to 18 Months ]

35.  Secondary:   Change in Left Ventricular End Diastolic Dimension (LVEDD) From Randomization to 24 Months   [ Time Frame: Randomization to 24 Months ]

36.  Secondary:   Change in Left Ventricular End Systolic Dimension (LVESD) From Randomization to 6 Months   [ Time Frame: Randomization to 6 Months ]

37.  Secondary:   Change in Left Ventricular End Systolic Dimension (LVESD) From Randomization to 12 Months   [ Time Frame: Randomization to 12 Months ]

38.  Secondary:   Change in Left Ventricular End Systolic Dimension (LVESD) From Randomization to 18 Months   [ Time Frame: Randomization to 18 Months ]

39.  Secondary:   Change in Left Ventricular End Systolic Dimension (LVESD) From Randomization to 24 Months   [ Time Frame: Randomization to 24 Months ]

40.  Secondary:   Change in Mitral Regurgitation From Randomization to 6 Months   [ Time Frame: Randomization to 6 Months ]

41.  Secondary:   Change in Mitral Regurgitation From Randomization to 12 Months   [ Time Frame: Randomization to 12 Months ]

42.  Secondary:   Change in Mitral Regurgitation From Randomization to 18 Months   [ Time Frame: Randomization to 18 Months ]

43.  Secondary:   Change in Mitral Regurgitation From Randomization to 24 Months   [ Time Frame: Randomization to 24 Months ]

44.  Secondary:   Change in Cardiac Index From Randomization to 6 Months   [ Time Frame: Randomization to 6 Months ]

45.  Secondary:   Change in Cardiac Index From Randomization to 12 Months   [ Time Frame: Randomization to 12 Months ]

46.  Secondary:   Change in Cardiac Index From Randomization to 18 Months   [ Time Frame: Randomization to 18 Months ]

47.  Secondary:   Change in Cardiac Index From Randomization to 24 Months   [ Time Frame: Randomization to 24 Months ]

48.  Secondary:   Change in Interventricular Mechanical Delay (IVMD) From Randomization to 6 Months   [ Time Frame: Randomization to 6 Months ]

49.  Secondary:   Change in Interventricular Mechanical Delay (IVMD) From Randomization to 12 Months   [ Time Frame: Randomization to 12 Months ]

50.  Secondary:   Change in Interventricular Mechanical Delay (IVMD) From Randomization to 18 Months   [ Time Frame: Randomization to 18 Months ]

51.  Secondary:   Change in Interventricular Mechanical Delay (IVMD) From Randomization to 24 Months   [ Time Frame: Randomization to 24 Months ]

52.  Secondary:   Change in E Wave/A Wave Ratio (E:A Ratio) From Randomization to 6 Months   [ Time Frame: Randomization to 6 Months ]

53.  Secondary:   Change in E Wave/A Wave Ratio (E:A Ratio) From Randomization to 12 Months   [ Time Frame: Randomization to 12 Months ]

54.  Secondary:   Change in E Wave/A Wave Ratio (E:A Ratio) From Randomization to 18 Months   [ Time Frame: Randomization to 18 Months ]

55.  Secondary:   Change in E Wave/A Wave Ratio (E:A Ratio) From Randomization to 24 Months   [ Time Frame: Randomization to 24 Months ]

56.  Secondary:   Clinical Composite Score at 6 Months   [ Time Frame: Randomization to 6 Months ]

57.  Secondary:   Clinical Composite Score at 12 Months   [ Time Frame: Randomization to 12 Months ]

58.  Secondary:   Clinical Composite Score at 18 Months   [ Time Frame: Randomization to 18 Months ]

59.  Secondary:   Clinical Composite Score at 24 Months   [ Time Frame: Randomization to 24 Months ]

60.  Secondary:   CRT-P and CRT-D System Implant Success   [ Time Frame: Initial Implant Procedure ]

61.  Secondary:   Incidence of Ventricular Tachyarrhythmias   [ Time Frame: Participants were followed for the duration of the study, an average of 37.9 months post-randomization among CRT-D subjects. ]


  Serious Adverse Events


  Other Adverse Events


  Limitations and Caveats
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Limitations of the study, such as early termination leading to small numbers of participants analyzed and technical problems with measurement leading to unreliable or uninterpretable data
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  More Information
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Certain Agreements:  
Principal Investigators are NOT employed by the organization sponsoring the study.
There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.


Results Point of Contact:  
Name/Title: BLOCK HF Clinical Trial Leader
Organization: Medtronic CRDM Clinical
phone: 763-526-2729
e-mail: medtroniccrmtrials@medtronic.com


Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):

Responsible Party: Medtronic Cardiac Rhythm and Heart Failure
ClinicalTrials.gov Identifier: NCT00267098     History of Changes
Other Study ID Numbers: 215
Study First Received: December 19, 2005
Results First Received: December 18, 2013
Last Updated: February 20, 2014
Health Authority: United States: Food and Drug Administration