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Medtronic Shock-Less Study on Physician Utilization of Shock Reduction Programming

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ClinicalTrials.gov Identifier: NCT00856349
Recruitment Status : Completed
First Posted : March 5, 2009
Results First Posted : July 3, 2014
Last Update Posted : July 3, 2014
Sponsor:
Information provided by (Responsible Party):
Medtronic Cardiac Rhythm and Heart Failure

Study Type Observational
Study Design Observational Model: Cohort;   Time Perspective: Prospective
Condition Cardiovascular Disease
Intervention Behavioral: Therapy Programming Report (TPR)
Enrollment 4384
Recruitment Details Subjects were enrolled in the Shock-Less study between April 2009 and January 2012 from 118 centers worldwide in North America, Central/South America, Australia/New Zealand and Asia.
Pre-assignment Details A total of 252 (6%) out of the 4384 enrolled subjects were excluded from the analysis cohort due to the following reasons: baseline device interrogation not available (217/252; 86%), inclusion/exclusion criteria not met (16/252, 6%), indication for ICD implant not specified (11/252; 4%), and VF therapy/detection not turned ON (8/252; 3%).
Arm/Group Title Analysis Cohort
Hide Arm/Group Description Enrolled subjects who met study eligibility criteria and contributed data toward the primary and/or secondary study endpoints.
Period Title: Overall Study
Started 4132
12 Month Follow-up 3228
18 Month Follow-up 2467
24 Month Follow-up 1698
Completed 3111
Not Completed 1021
Reason Not Completed
Death             418
Withdrawal by Subject             116
Lost to Follow-up             91
Protocol Violation             38
Physician Decision             13
Subject relocation             104
Device explant             33
Site closure             78
Subject changed Dr, insurance issue, etc             130
Arm/Group Title Analysis Cohort
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Enrolled subjects who met study eligibility criteria and contributed data toward study endpoints.

Therapy Programming Report (TPR): Center-specific therapy programming reports (TPRs) illustrating physician usage of shock reduction programming are provided to each center approximately 9-12 months after their first enrollment and monthly thereafter throughout the study.
Overall Number of Baseline Participants 4132
Hide Baseline Analysis Population Description
Enrolled subjects who met study eligibility criteria and contributed data toward study endpoints.
Age, Continuous  
Mean (Standard Deviation)
Unit of measure:  Years
Number Analyzed 4132 participants
66  (13)
Sex: Female, Male  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 4132 participants
Female
971
  23.5%
Male
3161
  76.5%
Race (NIH/OMB)  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 4132 participants
American Indian or Alaska Native
14
   0.3%
Asian
295
   7.1%
Native Hawaiian or Other Pacific Islander
9
   0.2%
Black or African American
360
   8.7%
White
3151
  76.3%
More than one race
5
   0.1%
Unknown or Not Reported
298
   7.2%
Region of Enrollment  
Measure Type: Number
Unit of measure:  Participants
 Number Analyzed 4132 participants
United States 3307
Taiwan 27
Hong Kong 15
Mexico 8
Canada 434
Argentina 19
Singapore 39
Australia 69
New Zealand 26
China 28
Korea, Republic of 24
India 118
Thailand 18
1.Primary Outcome
Title Change in Shock Reduction Programming Adoption
Hide Description

Change in percentage of subjects programmed to evidence-based target from baseline (pre-TPR distribution) to last follow-up (post-TPR distribution).

Shock-reduction programming parameters:

LIA (Lead Integrity Alert): Uploadable algorithm with the ability to increase the time between a lead fracture and potential delivery of an unnecessary shock.

SVT (Supraventricular Tachycardia) Limit: The maximum cycle length that Wavelet and PR logic will be applied to arrhythmias.

VF NID PP: Number of intervals to detect (NID) an arrhythmia in the VF zone for primary prevention (PP) patients.

VF NID SP: Number of intervals to detect (NID) an arrhythmia in the VF zone for secondary prevention (SP) patients.

Wavelet: Discriminator to help determine if arrhythmia is ventricular or supraventricular in single chamber ICDs.

PR Logic: Discriminator to help determine if arrhythmia is ventricular or supraventricular in dual chamber ICDs and CRT-Ds.
Time Frame Overall study (20 months on average)
Hide Outcome Measure Data
Hide Analysis Population Description
Subjects with paired baseline and follow-up programming data
Arm/Group Title Subjects With Paired Programming Data
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Subjects with paired baseline and follow-up programming data to evaluate changes in shock-reduction programming parameters
Overall Number of Participants Analyzed 2201
Measure Type: Number
Unit of Measure: percentage of participants
Increase in % on target (LIA) 13.6
Increase in % on target (SVT Limit) 6.8
Increase in % on target (VF NID PP) 9.0
Increase in % on target (VF NID SP) 3.5
Increase in % on target (Wavelet) 9.5
Increase in % on target (PR Logic) 3.2
Show Statistical Analysis 1 Hide Statistical Analysis 1
Statistical Analysis Overview Comparison Group Selection Subjects With Paired Programming Data
Comments LIA (Lead Integrity Alert): Uploadable algorithm with the ability to increase the time between a lead fracture and potential delivery of an unnecessary shock.
Type of Statistical Test Superiority or Other
Comments [Not Specified]
Statistical Test of Hypothesis P-Value <0.0001
Comments [Not Specified]
Method McNemar
Comments [Not Specified]
Method of Estimation Estimation Parameter Increase in % on target (LIA)
Estimated Value 13.6
Estimation Comments [Not Specified]
Show Statistical Analysis 2 Hide Statistical Analysis 2
Statistical Analysis Overview Comparison Group Selection Subjects With Paired Programming Data
Comments SVT (Supraventricular Tachycardia) Limit: The maximum cycle length that Wavelet and PR logic will be applied to arrhythmias.
Type of Statistical Test Superiority or Other
Comments [Not Specified]
Statistical Test of Hypothesis P-Value <0.0001
Comments [Not Specified]
Method McNemar
Comments [Not Specified]
Method of Estimation Estimation Parameter Increase in % on target (SVT Limit)
Estimated Value 6.8
Estimation Comments [Not Specified]
Show Statistical Analysis 3 Hide Statistical Analysis 3
Statistical Analysis Overview Comparison Group Selection Subjects With Paired Programming Data
Comments VF NID PP: Number of intervals to detect (NID) an arrhythmia in the VF zone for primary prevention (PP) patients.
Type of Statistical Test Superiority or Other
Comments [Not Specified]
Statistical Test of Hypothesis P-Value <0.0001
Comments [Not Specified]
Method McNemar
Comments [Not Specified]
Method of Estimation Estimation Parameter Increase in % on target (VF NID PP)
Estimated Value 9.0
Estimation Comments [Not Specified]
Show Statistical Analysis 4 Hide Statistical Analysis 4
Statistical Analysis Overview Comparison Group Selection Subjects With Paired Programming Data
Comments VF NID SP: Number of intervals to detect (NID) an arrhythmia in the VF zone for secondary prevention (SP) patients.
Type of Statistical Test Superiority or Other
Comments [Not Specified]
Statistical Test of Hypothesis P-Value 0.0116
Comments [Not Specified]
Method McNemar
Comments [Not Specified]
Method of Estimation Estimation Parameter Increase in % on target (VF NID SP)
Estimated Value 3.5
Estimation Comments [Not Specified]
Show Statistical Analysis 5 Hide Statistical Analysis 5
Statistical Analysis Overview Comparison Group Selection Subjects With Paired Programming Data
Comments Wavelet: Discriminator to help determine if arrhythmia is ventricular or supraventricular in single chamber ICDs.
Type of Statistical Test Superiority or Other
Comments [Not Specified]
Statistical Test of Hypothesis P-Value <0.0001
Comments [Not Specified]
Method McNemar
Comments [Not Specified]
Method of Estimation Estimation Parameter Increase in % on target (Wavelet)
Estimated Value 9.5
Estimation Comments [Not Specified]
Show Statistical Analysis 6 Hide Statistical Analysis 6
Statistical Analysis Overview Comparison Group Selection Subjects With Paired Programming Data
Comments PR Logic: Discriminator to help determine if arrhythmia is ventricular or supraventricular in dual chamber ICDs and CRT-Ds.
Type of Statistical Test Superiority or Other
Comments [Not Specified]
Statistical Test of Hypothesis P-Value <0.0001
Comments [Not Specified]
Method McNemar
Comments [Not Specified]
Method of Estimation Estimation Parameter Increase in % on target (PR Logic)
Estimated Value 3.2
Estimation Comments [Not Specified]
2.Secondary Outcome
Title Lead Integrity Alert (LIA) Performance
Hide Description Causes for LIA triggers reported during the study
Time Frame Overall study (20 months on average)
Hide Outcome Measure Data
Hide Analysis Population Description
Enrolled subjects who met study eligibility criteria and contributed data toward study endpoints.
Arm/Group Title Analysis Cohort
Hide Arm/Group Description:
Enrolled subjects who met study eligibility criteria and contributed data toward study endpoints.
Overall Number of Participants Analyzed 4132
Overall Number of Units Analyzed
Type of Units Analyzed: Subjects who experienced LIA triggers
 23
Measure Type: Number
Unit of Measure: percentage of subjects with LIA triggers
Lead fracture 30.4
Dislodgment 8.7
Connector issure 8.7
RV lead noise 8.7
VT/VF 8.7
EMI 4.3
Oversensing undefined 17.4
Unknown 17.4
3.Secondary Outcome
Title Reasons for Inappropriate Shocks
Hide Description Reasons for inappropriate shocks observed during the study
Time Frame Overall study (20 months on average)
Hide Outcome Measure Data
Hide Analysis Population Description
Enrolled subjects who met study eligibility criteria and contributed data toward study endpoints.
Arm/Group Title Analysis Cohort
Hide Arm/Group Description:
Enrolled subjects who met study eligibility criteria and contributed data toward study endpoints.
Overall Number of Participants Analyzed 4132
Overall Number of Units Analyzed
Type of Units Analyzed: Inappropriate shocks
 553
Measure Type: Number
Unit of Measure: percentage of inappropriate shocks
AF/AFL 56.4
Other SVT (sinus tach, atrial tach, etc.) 29.5
T-wave oversensing 6.9
Oversensing due to lead noise 6.0
Non-Sustained VT 0.5
Other 0.7
4.Secondary Outcome
Title Actions Taken Following a Shock
Hide Description Characterization of actions taken by the subject immediately following a device shock
Time Frame Overall study (20 months on average)
Hide Outcome Measure Data
Hide Analysis Population Description
Enrolled subjects who met study eligibility criteria and contributed data toward study endpoints.
Arm/Group Title Analysis Cohort
Hide Arm/Group Description:
Enrolled subjects who met study eligibility criteria and contributed data toward study endpoints.
Overall Number of Participants Analyzed 4132
Overall Number of Units Analyzed
Type of Units Analyzed: Subjects who experienced shocks
 421
Measure Type: Number
Unit of Measure: percentage of subjects with shocks
ER visit 28
Called follow-up clinic 23
Clinic visit 12.4
CareLink transmission 6.7
Off-hours follow-up clinician call 2.6
Urgent Care visit 0.7
Other 10.2
No action taken 29
5.Secondary Outcome
Title Barriers to Utilization of Shock Reduction Programming
Hide Description Characterization of barriers to physician utilization of shock reduction programming
Time Frame 24 months follow-up visit
Hide Outcome Measure Data
Hide Analysis Population Description
Enrolled subjects who met study eligibility criteria and contributed data toward study endpoints.
Arm/Group Title Analysis Cohort
Hide Arm/Group Description:
Enrolled subjects who met study eligibility criteria and contributed data toward study endpoints.
Overall Number of Participants Analyzed 1698
Overall Number of Units Analyzed
Type of Units Analyzed: Subjects not programmed to target
 27
Measure Type: Number
Unit of Measure: % of subjects not programmed to target
Physician preference 51.9
Medical history 7.4
Current subject condition 3.7
Utilization of nominal settings 3.7
Not reported 37
6.Secondary Outcome
Title Relationship of Subject Characteristics and Geographical Regions With Shock Reduction Programming Utilization
Hide Description Characterization of shock reduction programming utilization by subject characteristics and geographical regions
Time Frame Overall study (20 months on average)
Hide Outcome Measure Data
Hide Analysis Population Description
Enrolled subjects who met study eligibility criteria and contributed data toward study endpoints, with final programming data available post-TPR distribution.
Arm/Group Title Subjects With Final Programming Data Available
Hide Arm/Group Description:
Enrolled subjects who met study eligibility criteria and contributed data toward study endpoints, with final programming data available post-TPR distribution.
Overall Number of Participants Analyzed 3714
Measure Type: Number
Unit of Measure: percentage of participants
VF NID PP % on target - Male 31.6
VF NID PP % on target - Female 30.2
VF NID PP % on target - North America 31.1
VF NID PP % on target - Asia 31.2
VF NID PP % on target - ANZ 40.3
VF NID PP % on target - Central/South America 11.1
Time Frame [Not Specified]
Adverse Event Reporting Description Adverse events were not collected in this study
 
Arm/Group Title Analysis Cohort
Hide Arm/Group Description Enrolled subjects who met study eligibility criteria and contributed data toward study endpoints.
All-Cause Mortality
Analysis Cohort
Affected / at Risk (%)
Total   --/-- 
Show Serious Adverse Events Hide Serious Adverse Events
Analysis Cohort
Affected / at Risk (%)
Total   0/0 
Show Other (Not Including Serious) Adverse Events Hide Other (Not Including Serious) Adverse Events
Frequency Threshold for Reporting Other Adverse Events 0%
Analysis Cohort
Affected / at Risk (%)
Total   0/0 
[Not Specified]
Certain Agreements
Principal Investigators are NOT employed by the organization sponsoring the study.
There IS 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.
Generally, contracts allow investigators to publish study results per the protocol and publication plan. Investigators and Participating Institutions will provide any publication of Study Data generated by PI and/or Participating Institution to Medtronic for review prior to submission to determine if confidential information ("CI") is included and to check for technical correctness. Medtronic may not censor/interfere with the publication beyond the extent necessary to protect CI.
Results Point of Contact
Layout table for Results Point of Contact information
Name/Title: Daniel Lexcen, Clinical Research Specialist
Organization: Medtronic Cardiac Rhythm Disease Management
Phone: 763-526-9702
EMail: daniel.lexcen@medtronic.com
Layout table for additonal information
Responsible Party: Medtronic Cardiac Rhythm and Heart Failure
ClinicalTrials.gov Identifier: NCT00856349     History of Changes
Other Study ID Numbers: Shock-Less
First Submitted: February 26, 2009
First Posted: March 5, 2009
Results First Submitted: May 22, 2014
Results First Posted: July 3, 2014
Last Update Posted: July 3, 2014