Viewing Study NCT00037349



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Last Modification Date: 2024-10-26 @ 9:07 AM
Study NCT ID: NCT00037349
Status: COMPLETED
Last Update Posted: 2016-02-18
First Post: 2002-05-16

Brief Title: Heart Rate Recovery and Mortality
Sponsor: National Heart Lung and Blood Institute NHLBI
Organization: National Heart Lung and Blood Institute NHLBI

Study Overview

Official Title: None
Status: COMPLETED
Status Verified Date: 2005-01
Last Known Status: None
Delayed Posting: No
If Stopped, Why?: Not Stopped
Has Expanded Access: False
If Expanded Access, NCT#: N/A
Has Expanded Access, NCT# Status: N/A
Acronym: None
Brief Summary: To investigate whether impaired heart-rate recovery after exercise is a powerful and independent predictor of mortality
Detailed Description: BACKGROUND

Although there has been considerable attention paid to the prognostic significance of the heart rate rise during exercise only recently has it been noted that the heart rate fall after exercise or heart-rate recovery may be an even more powerful predictor of outcome Heart-rate recovery after exercise is a consequence of central reactivation of vagal tone As impaired parasympathetic function has been associated with increased risk of death the study tests the hypothesis that an impaired heart-rate recovery is a powerful and independent predictor of mortality

DESIGN NARRATIVE

The overall aim of this project was to use heart-rate recovery to substantially improve the prognostic value of the exercise test The specific aims of this project were 1 Derive biologically meaningful mathematical models of heart-rate recovery Data from over 20000 patients who had undergone exercise testing at Cleveland Clinic Foundation between 1990 and 1998 were used all of these patients had had their tests performed on exercise workstations which recorded heart rates every 10 seconds during and after exercise Heart-rate recovery measures were the difference between heart rate at peak exercise and heart rate at different points during recovery Modeling was based on exponential families using stepwise selection bootstrapping and information theory approaches Correlates of different patterns of heart rate recovery were determined 2 Using the results of modeling of heart-recovery derived from the work in Specific Aim 1 determined a prognostically defined optimal definition of abnormal heart rate recovery and demonstrated that an abnormal heart rate recovery was a powerful and independent predictor of mortality in diverse patient groups Data from exercise tolerance tests of over 40000 patients studied at the Cleveland Clinic Foundation between 1990 and 1999 were analyzed Statistical methods used included the nonparametric Kaplan-Meier product limit method and the Cox proportional hazards model with bootstrap validation which included use of the random forest technique 3 Using completely parametric techniques developed predictive survival models in which heart-rate recovery was included along with clinical data and other exercise findings including exercise capacity and heart rate changes during exercise The advantages of the parametric technique included a it allowed for modeling of nonproportional hazards that might permit differential strength of effect at different follow-up times for different sets of risk factors b it generated absolute risk not just relative risk and c it permitted patient-specific prediction

The study completion date listed in this record was obtained from the End Date entered in the Protocol Registration and Results System PRS record

Study Oversight

Has Oversight DMC:
Is a FDA Regulated Drug?:
Is a FDA Regulated Device?:
Is an Unapproved Device?:
Is a PPSD?:
Is a US Export?:
Is an FDA AA801 Violation?:
Secondary IDs
Secondary ID Type Domain Link
R01HL066004 NIH None httpsreporternihgovquickSearchR01HL066004