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Doppler-derived diastolic indices in dilated cardiomyopathy: a hemodynamic evaluation relating pre- and afterload
T Bartel1, S Muller, A C Borges
1Med. Klinik, Charité, Humboldt-Universität zu Berlin, Germany.
Insights
In dilated cardiomyopathy (DCM), early diastolic filling velocity is primarily determined by afterload, not preload. Hemodynamics, specifically pulmonary capillary wedge pressure and systemic vascular resistance, significantly influence this key indicator of heart function.
Area of Science:
- Cardiology
- Hemodynamics
- Diastolic Function
Background:
- Dilated cardiomyopathy (DCM) often presents with normal early diastolic filling velocity despite advanced heart failure.
- The underlying mechanisms for this finding, particularly the role of hemodynamics, require clarification.
Purpose of the Study:
- To elucidate the hemodynamic determinants of normal early diastolic filling velocity in DCM.
- To correlate Doppler-flow velocity parameters with indices of cardiac pre-load and after-load.
Main Methods:
- Twenty patients with DCM, excluding coronary and valvular heart disease, were studied.
- Simultaneous transmitral and transtricuspid Doppler echocardiography and hemodynamic measurements (including Swan-Ganz catheterization) were performed by blinded observers.
Main Results:
- Early diastolic filling velocity was significantly influenced by afterload parameters, including pulmonary capillary wedge pressure (PCWP) and systemic vascular resistance.
- Mitral early diastolic peak-flow velocity showed a strong correlation with PCWP and systemic vascular resistance index (r = 0.75; P < 0.001).
- Transtricuspid early diastolic peak-flow velocity correlated with right atrial pressure and pulmonary vascular resistance index.
Conclusions:
- A clear relationship exists between early diastolic Doppler indices and hemodynamic parameters in DCM.
- The functional interplay of pre-load and after-load is the primary determinant of early diastolic filling velocity in dilated cardiomyopathy.
Objective:
To explain the well known finding of a normal early diastolic filling velocity in advanced grade heart failure due to dilated cardiomyopathy (DCM) exclusively by hemodynamics and to relate Doppler-flow velocity parameters to indices representing pre- and afterload.
Design:
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 with DCM were enroled in the study after definitive exclusion of coronary and valvular heart disease.
Methods:
Diastolic transmitral and transtricuspid Doppler readings and hemodynamic measurements were done simultaneously 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 representing afterload. Pulmonary capillary wedge pressure (PCWP) was found to be directly related to early diastolic filling velocity. An inverse relation between early diastolic filling velocity and parameters representing afterload (systemic vascular resistance and mean arterial pressure) 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, the transtricuspid early diastolic peak-flow velocity was shown to be related to the equilibrium of right atrial pressure and pulmonary vascular resistance index. The atrial diastolic flow velocity parameters were found not to be related to hemodynamic indices.
Conclusion:
A definitive but not one-to-one relationship between early diastolic Doppler-flow indices and hemodynamic parameters was defined. A functional coupling of pre- and afterload can be considered the main determinant of early diastolic filling velocity in DCM.