Effect of Beta-blocker Therapy on QTc Response in Exercise and Recovery in Normal Subjects
Primary Purpose
Long QT Syndrome, Cardiac Repolarization
Status
Completed
Phase
Not Applicable
Locations
Study Type
Interventional
Intervention
Placebo
Propranolol LA
Sponsored by
About this trial
This is an interventional basic science trial for Long QT Syndrome focused on measuring QT interval, beta-blocker, exercise, electrocardiogram, repolarizaton
Eligibility Criteria
Inclusion Criteria:
- Healthy normal adults, age- and gender-matched to previously studied LQT1 subjects
Exclusion Criteria:
- Cardiac disease
- Diabetes
- Hypertension
- Severe allergic reaction
- Asthma requiring treatment
- Use of medications other than oral contraceptives, acetaminophen, nonsteroidal anti-inflammatory drugs, or synthroid or other thyroid medications
- Pregnancy (subjects will be asked if they are pregnant)
- Inability to sign informed consent
Sites / Locations
Arms of the Study
Arm 1
Arm 2
Arm Type
Placebo Comparator
Active Comparator
Arm Label
1
2
Arm Description
Subjects are assigned to placebo.
Subjects will take propranolol LA 80 mg daily for one week then 160 mg for one week followed by the exercise test.
Outcomes
Primary Outcome Measures
QTc Response to Exercise on Versus Off Beta-blocker.
To minimize the effect of heart rate on QT, QT was measured at heart rates between 100 and 110 beats per minute during exercise (on and off beta-blocker) and during recovery (on and off beta-blocker).
Secondary Outcome Measures
Tpeak-end Interval (Tpe)
Tpeak-end interval was measured at rest, exercise, and recovery on placebo and on propranolol.
Full Information
NCT ID
NCT00588965
First Posted
December 26, 2007
Last Updated
July 29, 2013
Sponsor
MetroHealth Medical Center
1. Study Identification
Unique Protocol Identification Number
NCT00588965
Brief Title
Effect of Beta-blocker Therapy on QTc Response in Exercise and Recovery in Normal Subjects
Official Title
Effect of Beta-blocker Therapy on QTc Response in Exercise and Recovery in Normal Subjects
Study Type
Interventional
2. Study Status
Record Verification Date
July 2013
Overall Recruitment Status
Completed
Study Start Date
August 2007 (undefined)
Primary Completion Date
December 2008 (Actual)
Study Completion Date
December 2008 (Actual)
3. Sponsor/Collaborators
Responsible Party, by Official Title
Principal Investigator
Name of the Sponsor
MetroHealth Medical Center
4. Oversight
Data Monitoring Committee
No
5. Study Description
Brief Summary
Background. In congenital long QT syndrome type 1 (LQT1), episodes of ventricular tachycardia are usually triggered by exercise and can be prevented in most patients by beta-blocker therapy. In addition, LQT1 associated with a normal resting QT interval can be unmasked by the abnormal QT response to exercise testing (failure of the QT interval to shorten normally). Preliminary data from our laboratory show that the exercise QT intervals of patients with LQT1 are partially normalized by beta-blocker therapy. It is still currently not known if beta-blockers modify the QT/heart rate relationship (a primary effect on repolarization) or if the "normalizing" effect is due to the inability of subjects on beta-blockers to attain sufficiently high workloads (due to reduced heart rate) for prolongation to occur. Moreover, the physiologic response of the exercise QT interval to beta-blockers in healthy control subjects is not known.
Objective. The objective of this study is to define the impact of beta-blocker therapy on the QT response to exercise and recovery in normal subjects.
Methods. Approximately 36 healthy adult subjects age-matched to previously studied LQT1 subjects will undergo 1) screening history, 2) two weeks of beta-blocker therapy ending in an exercise test, and 3) two weeks of placebo therapy ending in an exercise test. Beta blocker and placebo will be given in random order in a double-blind fashion. The QT response to exercise and recovery will be compared between drug-free and beta-blocker-treated states. These data will be compared to those previously collected for LQT1 subjects.
Implications. These results will provide new information about the effect of beta-blocker therapy on repolarization parameters in normal subjects, and will provide a context in which to interpret the previous findings that beta-blocker administration modifies the QT response to exercise in LQT1 subjects.
6. Conditions and Keywords
Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Long QT Syndrome, Cardiac Repolarization
Keywords
QT interval, beta-blocker, exercise, electrocardiogram, repolarizaton
7. Study Design
Primary Purpose
Basic Science
Study Phase
Not Applicable
Interventional Study Model
Crossover Assignment
Masking
ParticipantInvestigator
Allocation
Randomized
Enrollment
36 (Actual)
8. Arms, Groups, and Interventions
Arm Title
1
Arm Type
Placebo Comparator
Arm Description
Subjects are assigned to placebo.
Arm Title
2
Arm Type
Active Comparator
Arm Description
Subjects will take propranolol LA 80 mg daily for one week then 160 mg for one week followed by the exercise test.
Intervention Type
Drug
Intervention Name(s)
Placebo
Intervention Description
Placebo will be given 1 pill daily for a week, then 2 pills daily, followed by the exercise test.
Intervention Type
Drug
Intervention Name(s)
Propranolol LA
Intervention Description
Subjects will receive propranolol LA 80 mg one pill daily for 1 week then 2 pills daily for 1 week followed by exercise test.
Primary Outcome Measure Information:
Title
QTc Response to Exercise on Versus Off Beta-blocker.
Description
To minimize the effect of heart rate on QT, QT was measured at heart rates between 100 and 110 beats per minute during exercise (on and off beta-blocker) and during recovery (on and off beta-blocker).
Time Frame
2 weeks on each treatment then exercise test
Secondary Outcome Measure Information:
Title
Tpeak-end Interval (Tpe)
Description
Tpeak-end interval was measured at rest, exercise, and recovery on placebo and on propranolol.
Time Frame
Measured after 2 weeks on each intervention
10. Eligibility
Sex
All
Minimum Age & Unit of Time
18 Years
Maximum Age & Unit of Time
55 Years
Accepts Healthy Volunteers
Accepts Healthy Volunteers
Eligibility Criteria
Inclusion Criteria:
Healthy normal adults, age- and gender-matched to previously studied LQT1 subjects
Exclusion Criteria:
Cardiac disease
Diabetes
Hypertension
Severe allergic reaction
Asthma requiring treatment
Use of medications other than oral contraceptives, acetaminophen, nonsteroidal anti-inflammatory drugs, or synthroid or other thyroid medications
Pregnancy (subjects will be asked if they are pregnant)
Inability to sign informed consent
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Elizabeth S Kaufman, MD
Organizational Affiliation
MetroHealth Medical Center
Official's Role
Principal Investigator
12. IPD Sharing Statement
Learn more about this trial
Effect of Beta-blocker Therapy on QTc Response in Exercise and Recovery in Normal Subjects
We'll reach out to this number within 24 hrs