Heart Rate Dynamics in Response to Upper-Extremity Function Test to Identify Irreversible Frailty After Invasive Therapy in Older Adults with Advanced Heart Disease

PROJECT SUMMARY/ABSTRACT Advanced heart diseases lead to a reduced blood supply from the heart and consequently fatigue and deficits in performing physical activity. In the proposed research, we will assess the lack of physiological reserve in older adults with advanced heart disease, focusing on motor and cardiac function, to develop a novel, objective, quick, and accurate frailty score. We designed this approach to enhance candidate selection of older adults going through invasive therapies for advanced heart diseases. Although our approach is generic, to reduce between- subject variability we focus on transcatheter aortic valve replacement (TAVR) for older adult with aortic stenosis. Therapeutic options continue to grow for TAVR; however, it can be difficult to identify candidates with frailty level that prohibit them from tolerating the stress from aggressive therapy and those with potential reversible frailty. It is thus critically important to introduce meaningful routine objective frailty assessment into clinical care of cardiac patients. Frailty assessment is, however, not common in cardiology because current assessment tools are burdensome for older adults with advanced heart disease and impractical to implement in busy clinical environments. More importantly, no disease-specific tool is available to identify heart disease-related frailty. In continuation of our research program in the field of sensor-based frailty assessment, within our multidisciplinary team of engineers, cardiologists, and geriatricians, we propose the multimodal upper-extremity function (UEF) test for identifying frailty among older adults with advanced heart disease. UEF incorporates a synchronized system of motion sensors and electrocardiography (ECG) to measure motor performance and heart rate (HR) during a rapid 20-second elbow flexion task. Using our previously established UEF motion tracking component, we can precisely measure the level of deficits in motor performance (slowness, weakness, inflexibility, and fatigue), which are not detectable using eyeball assessment. Using the ECG setup, minimizing the motion artifact using this localized task, we accurately track HR response to the physical demand, as well as recovery behavior after the task. HR behavior during the task and recovery (HR dynamics) provide a measure of cardiac reserve associated with frailty in heart disease. We will further quantify dysregulation between HR response and motor demand as a novel measure of resilience. Based on our preliminary data, we expect a weaker and delayed HR response to physical activity as well as an impaired motor function due to frailty. The proposed research will be a four-year study at the University of Arizona Cardiovascular program. In the first arm, we will establish a new HR score and merge it with our previously validated UEF motor score to develop a multimodal frailty score among older adults with advanced heart disease (n=120). In the second arm, in a longitudinally setting we will validate the UEF multimodal frailty score for predicting TAVR complications for advanced heart disease (n=75). Accomplishing these aims, we will promote HR dynamic assessment for risk stratification of older adults with advanced heart disease, with huge potentials for other comorbid conditions.