According to the most recent information released by the American Heart Association, heart failure affects 5.8 million Americans and over 23 million people worldwide. In particular, diastolic heart failure (DHF) has emerged in approximately half of those suffering from heart disease and has become a major public health problem for many reasons, including the complexity of the disease, lack of effective drugs/therapies, requirement of invasive tests to diagnose and monitor DHF, and the absence of a suitable scientific model to study the disease. Scientists and physicians alike still do not fully understand what happens to the muscles in the heart (myocardium) patients who present with diastolic dysfunction or DHF. Therefore, the medical field is in need of an accurate model that can evaluate how diastolic dysfunction leads to heart failure and what happens at a cellular level as this disease emerges and progresses.
Our group has developed a mathematical model of the heart that gathers data from a procedure called an echocardiograph (echo) to analyze how muscles in the heart are functioning. This model incorporates how the heart muscle functions on a cellular level along with the overall functionality of the heart. We hypothesize that this model will measure the specific properties of the heart muscle that affect their ability to contract and relax. This study will determine whether these properties will be different in patients with DHF compared to healthy controls. We also propose that these abnormalities in the heart muscle will correlate with the patient's degree of heart failure and their prognosis when doctors evaluate using standard clinical tests. This study will be conducted at the University of Nebraska Medical Center (UNMC). 40 subjects will be enrolled, 20 healthy controls with no history of heart disease and 20 subjects who have been diagnosed with diastolic heart failure. Healthy controls will be required to undergo 1 echocardiograph procedure at UNMC. Subjects diagnosed with DHF will be required to undergo 6 echocardiograph procedure over the course of 2 years.
Study Type
OBSERVATIONAL
Enrollment
37
University of Nebraska Medical Center
Omaha, Nebraska, United States
The longitudinal assessment of myocardial properties in subjects with Diastolic Heart Failure.
Our mathematical model of the heart integrates the cellular mechanisms of sarcomere dynamics with the overall functional properties of the ventricle. Utilizing specific measurements captured by echo, estimates of basic muscle properties in subjects suffering from DHF will be compared to observed properties. Echo measurements will be taken at baseline and 2 weeks, 4 months, 8 months, 1 year, and 2 years following therapy.
Time frame: 2 years
Correlation of observed muscle properties to clinical outcomes/status.
Clinical outcome measurements, including hospitalizations, New York Heart Association (NYHA) class, and mortality, will be collected to determine effectiveness of current therapy for diastolic heart failure. By tracking patient outcomes and measured clinical endpoints, the degree of material parameter abnormality affecting clinical outcomes of subjects will be tested using multivariate regression with the material parameters derived from the model. The dependent variables and covariates such as age, sex, ejection fraction, presence of co-morbidities such as coronary artery disease, diabetes, and hypertension will also be included in the analysis.
Time frame: 2 years
Validation of the developing mathematical model using the data points collected from echocardiographic procedures
An optimization driver program that controls the parameter estimation has been developed and will be validated. To estimate unknown material parameters, multiple forward model simulations are obtained to estimate the partial derivatives of the least squares objective function with respect to the material parameters. Best-fit parameters will be determined for each DHF patient and each control using cylindrical, spherical and ellipsoidal models. Each of these parameters represents a unique aspect of sarcomere and ventricular matrix constitutive behavior. Best-fit material parameters for each patient will be compared with those obtained from the control groups.
Time frame: 1 baseline echocardiograph
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