Comparing Rate Response With CLS Versus Accelerometer ICD Settings in Heart Failure Patients With BIOTRONIK CRT-Ds (CLASS)
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ClinicalTrials.gov Identifier: NCT02693262 |
Recruitment Status :
Active, not recruiting
First Posted : February 26, 2016
Last Update Posted : May 12, 2020
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Condition or disease | Intervention/treatment | Phase |
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Heart Failure ICD Chronotropic Incompetence | Device: CLS Mode on Biotronik CRT-D Device: Accelerometer Mode on Biotronik CRT-D | Not Applicable |
This study is a prospective, randomized, single-blind crossover study intended to enroll patients who are implanted or are scheduled to be implanted with a Biotronik CLS and accelerometer capable CRT-D device. Patients will serve as their own control group with regard to modes of rate-adaptive pacing. Patients with a previously implanted Biotronik CRT-D device with CLS-capability will be recruited from health care institutions in San Diego and all dedicated functional testing will be performed at the University of California, San Diego (UCSD). The goal enrollment target for analysis will be 15 patients, with up to 20 patients enrolled to allow for withdrawals.
The purpose of this study is to evaluate whether changes to an implanted ICD can improve the functional status of patients with suspected chronotropic incompetence (CI). CI is a condition in which the heart rate is unable to adequately respond to meet the patient's physical demands, such as walking, climbing stairs, or doing household chores. CI is common in patients with cardiovascular disease, particularly in patients with heart failure. Common clinical management of patients with suspected CI is to activate an accelerometer setting in the cardiac resynchronization therapy with defibrillator (CRT-D) device. An accelerometer will adjust the heart rate to fit the physiological circumstances and needs of the patient based on patient movement only. BIOTRONIK is a company that has developed a novel technology included in the settings for CRT-D devices that offers CLS as an alternative to a standard accelerometer. CLS utilizes sensed electrical properties of the heart in order to assess what may be the best heart rate for both physical and mental demands. This study is designed to compare whether patients will benefit from CLS when compared with standard accelerometer technology.
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 15 participants |
Allocation: | Randomized |
Intervention Model: | Crossover Assignment |
Masking: | Single (Participant) |
Primary Purpose: | Treatment |
Official Title: | Rate Response With CLS Versus Accelerometer and Effect on Both Subjective Symptoms and Objective Outcomes in a Heart Failure Population Implanted With Cardiac Resynchronization With Defibrillator Device: The CLASS Trial |
Study Start Date : | July 2016 |
Estimated Primary Completion Date : | August 2020 |
Estimated Study Completion Date : | August 2020 |

Arm | Intervention/treatment |
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Experimental: CLS Mode on Biotronik CRT-D
All 15 patients will be randomized to this group. Their device will be set in the CLS mode for 1 week.
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Device: CLS Mode on Biotronik CRT-D
Setting changed and monitored. Quality of life evaluated through CPET, 6 Minute Walk Test, and Rand 36 Questionnaire. |
Active Comparator: Accelerometer Mode on Biotronik CRT-D
All 15 patients will be randomized to this group. Their device will be set in the accelerometer rate responsive mode for 1 week.
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Device: Accelerometer Mode on Biotronik CRT-D
Setting changed and monitored. Quality of life evaluated through CPET, 6 Minute Walk Test, and Rand 36 Questionnaire. |
- Cardiovascular health benefits from CLS versus accelerometer based rate responsive pacing [ Time Frame: three months ]To evaluate whether patients with left ventricular systolic heart failure implanted with CRT-D therapy who have evidence of chronotropic incompetence will benefit from CLS vs. accelerometer based rate responsive pacing. Objective measurements will be collected and analyzed from CPET and 6 Minute Walk Tests completed.
- Quality of life benefits from CLS versus accelerometer based rate responsive pacing [ Time Frame: three months ]To evaluate whether patients with left ventricular systolic heart failure implanted with CRT-D therapy who have evidence of chronotropic incompetence will benefit from CLS vs. accelerometer based rate responsive pacing in terms of the patient's quality of life (via RAND-36 Health Outcomes Questionnaire)

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Ages Eligible for Study: | 18 Years to 99 Years (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- Patients with a BIOTRONIK CRT-D device (capable of CLS and accelerometer rate responsive pacing)
- Patients at least 18 years old
- Patients who have plausible symptoms of CI based on previous monitoring and clinical symptoms
Exclusion Criteria:
- Pregnant patients
- Patients who are unwilling/unable to provide informed consent
- Patients who are unable to complete study related procedures
- Current persistent atrial fibrillation

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02693262
United States, California | |
Sulpizio Cardiovascular Center | |
La Jolla, California, United States, 92037 |
Principal Investigator: | Jonathan Hsu, MD | University of California, San Diego |
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | Jonathan Hsu, Assistant Professor of Medicine, University of California, San Diego |
ClinicalTrials.gov Identifier: | NCT02693262 |
Other Study ID Numbers: |
151774 |
First Posted: | February 26, 2016 Key Record Dates |
Last Update Posted: | May 12, 2020 |
Last Verified: | May 2020 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
defibrillator heart failure ICD CRT-D cardiac resynchronization therapy |
rate response CLS closed-loop stimulation accelerometer chronotropic incompetence |
Heart Failure Heart Diseases Cardiovascular Diseases |