Comparing Rate Response With CLS Versus Accelerometer ICD Settings in Heart Failure Patients With BIOTRONIK CRT-Ds

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.