RESUMO
Objective: To determine whether reduction in central pressure augmentation and central systolic blood pressure by nitroglycerine (NTG) results from effects on pre-load or is due to arterial dilation. Methods: We compared effects of NTG with those of lower body negative pressure (LBNP). Hemodynamic measurements were made at rest, during LBNP (10, 20 and 30 mmHg, each for 15 min) and after NTG (10, 30 and 100 μg/min, each dose for 15 min) in ten healthy volunteers. Cardiac pre-load, stroke volume and cardiac output were assessed by echocardiography. Central pressure augmentation and central systolic pressure were obtained by radial tonometry using a transfer function. Results: LBNP (20 mmHg) and NTG (30 μg/min) reduced pre-load (as measured by the peak velocity of the S wave in the superior vena cava) to a similar degree [by (26.8 ± 3.8)% and (23.9 ± 3.4)%, respectively]. Compared to LBNP, NTG reduced systemic vascular resistance [by (32.9± 7.5)%, P<0.01], decreased peripheral and central pressure augmentation [by (20.8 ± 3.4)% units and (12.9 ± 2.9)% units, respectively, each P<0.01]. Conclusion: These results suggest that a reduction in pre-load does not explain reduction in pressure augmentation and central systolic blood pressure by NTG and that these effects are mediated through arterial dilation.
RESUMO
Objective To investigate the relationship and clinical significance of blood plasma brain natriuretic peptide (BNP) and Keshan Disease (KD). Methods Seventy KD patients and 30 healthy volunteers in endemic area were investigated with Doppler Echocardiography for the measurement of left ventricular end-diastolic diameter(LVEDD) and left ventricular ejection fraction (LVEF), and the plasma BNP levels were determined with microparticle enzyme immunoassay. Results The BNP levels in plasma in KD patients [(444.61±102.31), (87.21±23.15)ng/L] were significantly higher than that of healthy volunteers [(34.91±15.21)ng/L],the differencesbeing statistical significant (q=39.74,5.82,P<0.01). The BNP levels in chronic KD patients were higher than that of latent KD patients (q=37.62,P<0.01). The plasma BNP levels in KD patients with LVEDD 60 nun [(928.80±134.27)ng/L] were significantly higher than those of patients with LVEDD 55～60 mm [(89.24±52.31)ng/L] and LVEDD<55 nun [(67.14±6.92)ng/L],the differencesbeing statistical significant (q=44.30,48.16, P<0.01), The plasma BNP levels in KD patients with LVEF<35%[(1654.21±421.35) ng/L] were significantly higher than those of patients with 35% ~ 50%[(421.54±112.32)ng/L] and50% [ (81.21±72.85 ng/L)], the differencesbeing statistical significant(q=24.91,72.66, P<0.01), The BNP levels in LVEF 35%～50% were higher than that of 50% (q=11.84,P<0.01). Conclusion The plasma BNP levels were important for the diagnosis, grouping, therapeutic effect and prognostic evaluation of KD.