RESUMO
The combination of coronary heart disease (CHD) with increased left ventricular wall mass (LVWM) appears associated with prolonged isovolumetric relaxation (IVR) and consequently, alterations in the rapid filling phase. Methylxanthine-substances may improve relaxation through inhibition of phosphodiesterase activity. Accordingly we examined multiple indexes of left ventricular diastolic function before and after administration of 200 mg pentoxifylline (Trental) intravenously to 18 patients (51.3 +/- 9.0 years, 15 males, three females) with stable angina pectoris and positive exercise-ECG in NYHA class I or II and LVWM greater than 160 g (n = 9) and less than or equal to 160 g (n = 9). Left ventricular pressure (P) and volume (V) measurements were made with a high-fidelity-micromanometer before and twelve minutes after administration of pentoxifylline. The time constant of left ventricular isovolumic relaxation (T), usual global left ventricular volumes and derived indexes such as peak filling rate (PFR), time to peak filling rate (TPFR), segmental (relaxation and rapid filling phases) and total pressure-volume relationship before and after pentoxifylline were calculated. Significant differences between these two groups (greater than/less than or equal to 160 g LVWM) were found for end-diastolic volume (68.7 +/- 19.0 to 90.8 +/- 22.6 ml/sqm), end-systolic volume (21.7 +/- 16.0 to 36.1 +/- 14.7 ml/sqm), end-diastolic pressure (15.0 +/- 4.8 to 15.7 +/- 5.1 mm Hg), PFR (3.25 +/- 1.18 to 2.66 +/- 0.71 s-1), T (46.0 +/- 5.7 to 52.7 +/- 7.2 ms), the linear regression of lnP-V (lny = -0.117 x + 4.59 to lny = -0.091 x + 4.75) in the IVR-phase (dp/dtmin less than or equal to x less than or equal to 80 ms) (leftward shift in p-V-relationship when less than or equal to 160 g) and the complet p-V-areas. After pentoxifyl-line-administration there were significant decreases in T in patients with increased LVWM (52.7 +/- 7.2 to 47.7 +/- 5.9 ms) and the P-V-product over the time in the rapid filling phase in patients with LVWM less than or equal to 160 g. Total peripheral resistance and heart rate did not change. These changes in parameters of left ventricular diastolic function in combination with significant improvement of pump function especially in patients with LVWM greater than 160 g after administration of pentoxifylline suggest that improved diastolic function is the result of a direct myocardial effect of pentoxifylline.
