[Prognostic relevance of left ventricular diastolic function parameters in dilated cardiomyopathy]

Abstract

Patients with dilated cardiomyopathy (DCM) generally have an impaired functional capacity and poor long-term out-comes. A mortality of 5-15% per year has been described actually. Aim of this study was to verify the prognostic relevance of invasive and non-invasive parameters of diastolic function in patients with DCM. In 33 patients with DCM, cardiac catheterization was performed and left ventricular systolic (ejection fraction (EF; %)); left ventricular enddiastolic pressure (LVEDP; mmHg) and diastolic function (time constant of relaxation (T, ms); the constant of myocardial stiffness (b) were derived from biplane laevocardiography and simultaneous micromanometric registration of pressure-volume curves. For evaluation of clinical out-come, the follow-up period was defined as beginning on the day after cardiac catheterization and ending on the most recent date or with a cardiac event (death or cardiac transplantation). All patients were reevaluated for NYHA functional class and completed a standard questionnaire. The following hemodynamic parameters were evaluated: invasive parameters of left ventricular diastolic function (constant of relaxation: tau (ms), constant of myocardial stiffness: b)), as well as parameters of systolic function (ejection fraction (EF; %)), left ventricular pressure (LVEDP; mmHg), left ventricular muscle mass index (LVMMI; g/m2), left ventricular enddiastolic volume index (LVEDVI; ml/m2) and non-invasive parameters of morphological data, left ventricular systolic (fractional shortening (FS, %) and ejection fraction) and diastolic parameters with echocardiography. During the follow-up period of 36 months, 11 of 33 patients experienced a major cardiac event (cardiac death n = 8, heart transplantation n = 3). The major cause of death was progressive pump failure. The remaining 22 patients were further classified with respect to changes in functional status. While clinical symptoms could be improved medically in patients with moderate increase of myocardial stiffness, patients with severe increase of myocardial stiffness (b: 76.1 +/- 12.1 vs 17.9 +/- +8.1, p < 0.001) could not be improved and suffered more cardiac events. Doppler echocardiographic measurements in these patients showed a restrictive filling pattern (VE 0.91 +/- 0.21 vs 0.64 +/- 0.18 m/s; p < 0.01; VA 0.52 +/- 0.23 vs 0.57 +/- 0.24 m/s; p < 0.01, deceleration time 129 +/- 17 vs 211 +/- 14 ms; p < 0.01). The medical heart failure therapy was comparable in both groups. In patients with cardiac events, the diastolic left ventricular variables did not significantly differ between patients who underwent heart transplantation and those who died. Patients who demonstrated a sole impairment of relaxation (tau: > 50 ms) suffered no cardiac events. Impaired diastolic function contributes to the clinical picture of congestive heart failure. Parameters of left ventricular diastolic function are powerful and important predictors of major cardiac events in patients with DCM, like heart transplantation and non-sudden death, and may indicate future clinical success of medical treatment. Invasive and non-invasive parameters of diastolic function reveal comparable information for the estimation of prognosis of patients with DCM in order to initiate early therapy.