Regional Left Ventricular Fiber Stress Analysis for Cardiac
Resynchronization Therapy Response.
Cardiac resynchronization therapy (CRT) is an effective treatment for a
subgroup of heart failure patients, but more than 30 % of those
selected do not respond. Inadequate criteria for patient selection and
optimization are the main causes of the high non-response rate.
Mechanical parameters, such as work done during the isovolumetric phase,
are promising, but are complicated and require invasive measurements. In
this study, we use a computational modeling framework to calculate the
regional stress of the left ventricular wall of seven CRT patients and
seven healthy controls. The standard deviation of the regional wall
stress at the time of mitral valve closure (SD_MVC) was used to
quantify dyssynchrony and was compared between patients and controls and
among the patients. The results show that SD_MVC is significantly lower
in controls compared to patients and correlated with the degree of
long-term response among the patients based on end-diastolic volume
reduction. The patients with lower SD_MVC responded best to therapy.
The patient with the highest SD_MVC was the only non-responder in the
cohort. The distribution of fiber stress at the beginning of the
isovolumetric phase seems to correlate with the degree of response and
this parameter could potentially improve patient selection and
optimization of CRT. Further studies with a larger cohort are needed to
validate these results.