Mitral Ring Motion and Transmitral Blood Flow Velocity in Dilated Cardiomyopathy

Mitral ring motion and indices of left ventricular diastolic filling were measured by M-mode and Doppler echocardiography in apical 4 chamber view in 11 dilated cardiomyopathy patients and 9 normal subjects without clinical evidence of heart disease.

The mean age of patients was 52 years and average heart rate was 76 beats/min. The parameters of mitral annulus motion include earley relaxation amplitude(ER), late atrial contraction amplitude(AC) and A2-peak excursion(A2-PE). Transmitral flow velocity parameters include peak flow velocity of early diastolic flow velocity(PFVE), peak flow velocity of late atrial contraction(PFVA), the ratio between early and late peak flow velocity(PFVE/PFVA), Acceleration rate of early diastolic peak flow(AR), deceleration rate of early diastolic peak flow(DR), time velocity integral of early diastolic flow velocity(TVIE), time velocity integral of late atrial contraction flow velocity(TVIA) and ratio between early diastolic and late atrial flow velocity integral(TVIE/TVIA).

In patients with dilated cardiomyopathy, ER(4.5±2.3mm) and AC(2.3±1.6mm) were significantly decreased than normal(10.7±2.6mm, 6.6±1.6mm, p<0.01, p<0.01, respectively), whereas ER/AC(1.7±0.7) was not significantly different than normal subjects(1.6±0.5). A2-PE(100±80 msec) was significantly delayed in dilated cardiomyopathy patients than normal subjects(35±25 msec, p<0.01).

In analysis of transmitral flow velocities, PFVE, PFVA and PFVE/PFVA, etc were not significantly different compared to normal subjects in patients with dilated cardiomyopathy.

Mitral ring motion amplitude was decreased and A2-peak excursion time interval(A2-PE) was delayed in patients with dilated cardiomyopathy, but transmitral flow velocities were not significantly different from normal subjects in patients with dilated cardiomyopathy. These results reflect the facts that early diastolic relaxation amplitude is decreased by the change of compliance of LV and late atrial contractin amplitude is decreased by decrease of atrial contractility and increased stiffness of LA and LV. Despite of decreased mitral ring motion, transmitral flow velocity is not significantly different compared to normal subjects in patients with dilated cardiomyopathy. From these evidences, not only transmitral flow velocity affected by multiple factors but also mitral ring motion affected by LA and LV function are considered in assessment of LV diastolic dysfuction.