Pilot Study to Investigate the Creation of Physiological Rhythm by Closed Loop Stimulation in hEart Failure pAtients With chronoTropic incompEtence

In patients with pharmacological refractory heart failure (HF), systolic dysfunction, and cardiac dyssynchrony, the cardiac resynchronization therapy (CRT) reduces the risk of death, and improves symptoms and quality of life. A considerable portion (80%) of patients with a CRT indication has a chronotropic incompetence (CI). CI usually induces a stress intolerance which negatively affects the quality of life. In addition of being a marker of diminished exercise capacity, severe CI (sCI) may be an independent predictor of mortality. The sensor-based rate adaption provided by the implanted CRT device delivers a possible therapeutic approach for the CI. Usually, rate adaption is achieved by an accelerometer. The previous studies in terms of effectiveness of rate adaption in CRT patients with CI showed inconsistent results. In addition to an accelerometer to deliver the rate adaption BIOTRONIK provides closed loop stimulation (CLS) as unique feature in a CRT device. CLS determines the appropriate heart rate based on intra-cardiac impedance measurements. These measurements reflect changes of the cardiac contraction dynamics in reaction to information coming from the autonomic nervous system. CLS takes the information on the contraction dynamics and translates it into an adequate heart rate adaptation, thus delivering physiologically appropriate therapy.