DOPPLER-DERIVED DIASTOLIC INDEXES IN DILATED CARDIOMYOPATHY - A HEMODYNAMIC EVALUATION RELATING PRELOAD AND AFTERLOAD PARAMETERS TO FLOW VELOCITY

OBJECTIVE: To explain the well known finding of a normal early diastol ic filling velocity in advanced grade heart failure due to dilated car diomyopathy (DCM) exclusively by hemodynamics and to relate Doppler-fl ow velocity parameters to indices representing pre- and afterload. DES IGN: DCM was hypothesized to be a disorder in which pre- and afterload contribute in equal proportion to cardiac insufficiency independently from ischemic impairment of relaxation. PATIENTS: Twenty patients wit h DCM were enroled in the study after definitive exclusion of coronary and valvular heart disease. METHODS: Diastolic transmitral and transt ricuspid Doppler readings and hemodynamic measurements were done simul taneously by two blinded observers. A Swan-Ganz catheter was employed. MAIN RESULTS: Simple and multiple regression analyses revealed early diastolic filling velocity to depend on hemodynamic parameters represe nting afterload. Pulmonary capillary wedge pressure (PCWP) was found t o be directly related to early diastolic filling velocity. An inverse relation between early diastolic filling velocity and parameters repre senting afterload (systemic vascular resistance and mean arterial pres sure) was demonstrated; however the most significant correlation using multiple regression analysis was shown between mitral early diastolic peak-flow velocity (dependent) and PCWP as well as systemic vascular resistance index (independents) (r=0.75; P<0.001). Correspondingly, th e transtricuspid early diastolic peak-flow velocity was shown to be re lated to the equilibrium of right atrial pressure and pulmonary vascul ar resistance index. The atrial diastolic flow velocity parameters wer e found not to be related to hemodynamic indices. CONCLUSION: A defini tive but not one-to-one relationship between early diastolic Doppler f low indices and hemodynamic parameters was defined. A functional coupl ing of pre- and afterload can be considered the main determinant of ea rly diastolic filling velocity in DCM.