Kinematic modeling of short-axis tissue motion revealed that longitudinal and radial parameters are highly correlated (R = 0.69 and 0.92) in subjects with normal diastolic function.
Observational (n=10)
A novel kinematic model of short-axis tissue motion provides radial left ventricular stiffness and relaxation indexes that correlate highly with longitudinal parameters in healthy subjects and differ substantially in pathological states.
Effect estimate: R = 0.69 and 0.92
Traditionally, global and longitudinal (i.e., regional) left ventricular (LV) diastolic function (DF) assessment has utilized features of transmitral Doppler E and A waves or Doppler tissue imaging (DTI)-derived mitral annular E' and A' waves, respectively. Quantitation of regional DF has included M-mode echocardiography-based approaches and strain and strain rate imaging (in selected imaging planes), while analysis of mitral annular "oscillations" has recently provided a new window into longitudinal (long-axis) function. The remaining major spatial degree of kinematic freedom during diastole, radial (short-axis) motion, has not been fully characterized, nor has it been exploited for its potential to provide radial LV stiffness (k'(rad)) and relaxation/damping (c'(rad)) indexes. Prior characterization of regional (longitudinal) DF used only annular E'- and A'-wave peak velocities or, alternatively, myocardial strain and strain rate. By kinematically modeling short-axis tissue motion as damped radial oscillation, we present a novel method of estimating k'(rad) and c'(rad) during early filling. As required by the (near) constant-volume property of the heart and tissue/blood incompressibility, in subjects (n = 10) with normal DF, we show that oscillation duration-determined longitudinal (k'(long) and c'(long)) and radial (k'(long) and c'(rad)) parameters are highly correlated (R = 0.69 and 0.92, respectively). Selected examples of diabetic and LV hypertrophic subjects yield radial (k'(long) and c'(rad)) parameters that differ substantially from controls. Results underscore the utility of the incompressibility-based causal relation between DTI-determined mitral annular long-axis (longitudinal mode) and short-axis (radial mode) oscillations in healthy subjects. Selected pathological examples provide mechanistic insight and illustrate the value and potential role of regional (longitudinal and radial) DF indexes in fully characterizing normal vs. impaired DF states.
Riordan et al. (2007) conducted an observational in Normal diastolic function, diabetes, left ventricular hypertrophy (n=10). Kinematic modeling of short-axis tissue motion vs. Controls (normal diastolic function) was evaluated on Correlation between oscillation duration-determined longitudinal and radial parameters (R = 0.69 and 0.92). Kinematic modeling of short-axis tissue motion revealed that longitudinal and radial parameters are highly correlated (R = 0.69 and 0.92) in subjects with normal diastolic function.