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

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

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

Brief Summary:

Heart failure is a progressive disease that decreases the pumping action of the heart. This may cause a backup of fluid in the heart and may result in heart beat changes. When there are changes in the heartbeat, sometimes a pacemaker is used to control the rate and rhythm of the heartbeat. In this trial, the researchers will test if pacing both the left and right lower half of the heart (ventricles) will:

  • decrease the number of hospital and clinic visits due to heart failure symptoms
  • extend life
  • delay heart failure symptoms as compared to those who are paced in only one ventricle (the right ventricle)

Detailed Summary:
Sponsor: Medtronic Cardiac Rhythm and Heart Failure

Current Primary Outcome: 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. ]

Events include all-cause mortality, heart failure(HF)-related urgent care (a healthcare utilization visit involving intravenous(IV) therapy for heart failure) or significant increase(at least 15%) in LVESVI (a measure of the volume of a patient's left ventricle) from randomization to a later time point. Time from randomization until the subject experienced one of these events served as the outcome measure. LVESVI endpoints occurred primarily at those visits in which LVESVI measurements were required (6, 12, 18, 24 months). Because endpoints such as death or HF urgent care could occur at any time during follow-up, the subject's outcome measure could range from less than 1 month to 105 months (maximum follow-up duration). Primary endpoints and follow-up data occurring after a subject missed a required LVESVI measurement were excluded from the analysis and the table below. The counts reflect the number of subjects meeting each endpoint, and are not necessarily mutually exclusive.


Original Primary Outcome:

  • The events that will be measured in this trial are:
  • • Effectiveness of the heart's pumping ability
  • • Urgent care admissions
  • • Subject longevity


Current Secondary Outcome:

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

    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).

  • 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. ]
    The endpoint will be a subject's time from randomization to either their first heart failure-related hospitalization, or death.
  • 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. ]

    The endpoint will be the time from randomization to either death or a visit (6, 12, 18, 24 month or interim visit) in which the subject undergoes an echocardiogram and the measured left ventricular end systolic volume index (a measure of the size of the subject's left ventricle normalized over their body surface area) is at least 15% greater than the corresponding measured value at randomization.

    Only LVESVI endpoints/deaths and follow-up data occurring before a subject missed an LVESVI measurement (due to missed visit, echo not performed, etc.) were used in the analysis and included in the table below. The counts reflect the number of subjects meeting each endpoint, and are not mutually exclusive.

  • First Heart Failure Hospitalization [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]
    The endpoint is the time from randomization to a subject's first heart failure (HF)-related hospitalization. For each randomization arm, the number of subjects who met the endpoint, experiencing at least one heart failure-related hospitalization post-randomization, are reported, as well as the number of randomized subjects who did not experience any HF hospitalizations post-randomization.
  • Days Hospitalized for Heart Failure [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]
    For each subject the endpoint was the days hospitalized for heart failure per patient year, calculated as the total number of days the subject was hospitalized for heart failure divided by the subject's total follow-up time. Only post-randomization data were used.
  • Change in New York Heart Association Classification [ Time Frame: Randomization to 24 Months ]
    The endpoint is a subject's change in New York Heart Association Classification (a measure of the degree of heart failure a subject has on a 4 class scale, with NYHA I being the healthiest score and NYHA IV being the sickest score) from randomization to each of four time points: 6 months, 12 months, 18 months, and 24 months post-randomization. The change categories listed will be relative to randomization.
  • Change in Heart Failure Stage [ Time Frame: Randomization to 24 Months ]
    The endpoint is a subject's change in Heart Failure Stage (a measure of the degree of heart failure a subject has on a 4 stage scale (A, B, C, D), with Class A being the healthiest score and Class D being the sickest score) from randomization to each of four time points: 6 months, 12 months, 18 months, and 24 months.
  • Change in Cardiovascular Medications [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]
    The endpoints are what classes of drugs (e.g. Beta blockers, Diuretics, Nitrates, etc.) each subject was on at the time of scheduled visits (e.g Randomization, 6 months, 12 months, etc.)
  • 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. ]
    Adverse events that subjects experienced after they were randomized were compared between arms with regard to several categories such as heart failure (HF)-relatedness, relatedness to the implant procedure, and relatedness to the implanted system, including individual components such as the left ventricular (LV) lead and the CRT-P or CRT-D generator.
  • Cardiovascular-related Healthcare Utilizations [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]
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    Original Secondary Outcome: Individual elements of the primary objective will be analyzed separately. Comparisons will also be made between treatment and control groups for: changes in subject heart failure status, cardiovascular medications, and quality of life.

    Information By: Medtronic Cardiac Rhythm and Heart Failure

    Dates:
    Date Received: December 19, 2005
    Date Started: December 2003
    Date Completion:
    Last Updated: February 20, 2014
    Last Verified: February 2014