BACKGROUND: Low frequency oscillation of systemic artery pressure was known as the marker of sympathetic modulation. Recently the low frequency oscillation of pulmonay artery pressure in pulmonary hypertensive patient was reported. But no further study about its quantitative relationshop and phasic coupling between the low frequency oscillation of pulmonary artery pressure and systemic artery pressure. Power spectral analysis with autoregressive algorithm and cross spectral analysis are powerful tool for investigation these relationship. METHOD: Analog signals of simultaneous measured left pulmonary and femoral artery pressure in thirty one patients with ventricular septal defect were digitized and stored. After modeling each time series with autoregressive algorithm, power spectral density function was obtained by calculation the frequency response function of each model, and then low frequency power was computed. Cross spectral density function provided squared coherence and phase spectrum. Phase between the low frquency oscillation of the two signal was measured from the phase spectrum when the squared coherence is above 0.5. RESULTS: The advantage of using autoregressive model was that the power spectral density function was continous and sharp spectral peak was usually found. In patients with Rp/Rs<0.25, the low frquency power of pulmonary artery pressure(12+/-12) was significantly smaller than that of the systemic artery pressure(144+/-242). In patients with Rp/Rs>or=0.25, there was no significant difference between the low frequency power of pulmonary artery pressure(384+/-461) and that of the systemic artery pressure(752+/-1241). In patients with Rp/Rs>or=0.25, it was more probable that low frequency oscillation of pulmonary and systemic artery pressure was timely coherent(sqaured coherence>0.5) than in patient with Rp/Rs<0.25. And their phase difference was 0~1.96 radian. CONCLUSION: Autoregressive algorithm is a more powerful tool for spectral analysis than the method of conventional spectrum estimation. When pulmonary vascular resistance remains low, the low frequency oscillation of pulmonary artery pressure was negligible compared to systemic artery pressure. But as pulmonary vascular resistance elevates, the low frequency power of pulmonary artery pressure is much the same as that of systemic artery pressure, and there is a explicit time realtionship that pulmonary artery pressure leads the systemic artery pressure about 0~3 seconds in the low frequency range.
Arteries ; Femoral Artery ; Heart Septal Defects, Ventricular ; Humans ; Hypertension, Pulmonary ; Pulmonary Artery ; Pulmonary Circulation* ; Vascular Resistance

No abstract available.
Female ; Fetal Heart* ; Fractals* ; Heart Rate, Fetal* ; Pregnancy

BACKGROUND: We studied how periodic and complex heart rate dynamic changes as pulmonary artery pressure increases in 32 infants with ventricular septal defet. In addition, we tested the possibility that the dynamical changes can be used to noninvasively predict the pulmonary artery pressure. METHODS: During cardiac catherterization, mean pulmonary artery pressure was measured and, at the same time, 5minute segments of continous electrocardiographic recording was stored. High-(>0.15 hertz) and low-(0.03-0.15 hertz) frequency components of heart rate variability were computed using spectral analysis. Yhe overall complexity of heart rate time series was quantified by its approximate entropy. RESULT: Pulmonary hypertensive infants(mean pulmonary artery pressure>20mmHg, n=17) had significantly lower low-(p<0.05)and high-(p<0.05) frequency power and lower approximate entropy(p<0.0001) than pulmonary normotensive infants(mean pulmonary artery pressure20mmHg, n=15). The mean pulmonary artery pressure was significantly correlated not with the spectral powers but with approximate entropy(=-0.51, P=0.0001). Conclusion: It can be concluded that, in infants, pulmonary hypertension induced by left-to-right shunt lesions suppress both periodic and complex heart rate oscillation and that mean pulmonary artety pressure can be predicted by calculating approximate entropy of heart trate variability.
Electrocardiography ; Entropy ; Heart Rate* ; Heart Septal Defects, Ventricular* ; Heart* ; Humans ; Hypertension, Pulmonary ; Infant* ; Pulmonary Artery*

No abstract available.
Durapatite* ; Radionuclide Imaging*

No abstract available.
HIV* ; Humans ; Humans* ; Lymphocytes* ; Zidovudine*

BACKGROUND: It is well known that systemic blood pressure oscillates with low(0.04~0.1Hz), mid(0.1~0.15Hz), and high(respiratory) frequency range. But there has been no study about oscillation of pulmonary artery pressure(PAP). METHOD: We measured PAP for 5 minutes in 32 patients of ventricular septal defect and stored them to computer files. Power spectral density curve was obtained. Low, mid, respiratory frequency power were measured by integrating the area within each frequency range below the power density curve. RESULT: The incidence of significant low frequency power(more than 5% of total power) were higher in patients of high PAP and hign Rp/Rs than those of low PAP and Rp/Rs(p<0.01 and p<0.005 respectively). The low frequency power positively correlates with PAP and Rp/Rs(r=0.62, p<0.0005 and r=0.61, p=0.0005 respectively). CONCLUSION: It can be said conclusively that as PAP and pulmonary vascular resistance elevates, the PAP tends to definitively oscillate in low frequency range.
Blood Pressure ; Heart Septal Defects, Ventricular ; Humans ; Incidence ; Pulmonary Artery* ; Vascular Resistance

Horseshoe kidney is a nonfatal anomaly of renal development characterized by fusion of one poles of both kidneys. Most clinical problems are caused by infection, hydronephrosis and renal calculi. Herein, we report a case of horseshoe kidney with staghorn calculi and hydronephrosis in a 66 year-old-woman. The patient was managed by division of the isthmus and left nephrectomy with a good result.
Calculi* ; Humans ; Hydronephrosis* ; Kidney Calculi ; Kidney* ; Nephrectomy

BACKGROUND: The effectiveness for vagal stimulation by ice water aplication to face during metronome-controlled respiration of 15 breaths/minute was examed. The importance of basal vagal tone and sympathovagal interaction in the individual variability of responsiveness to the vagal stimulation was investigated. METHOD: Fifty three 12~13 year old healthy volunteers were included. Vagal tone and sympathovagal interaction before and after application of ice water to the face were assessed by power spectral analysis of RR interval(heart rate) variability. RESULT: Basal heart rate, high frequency power, and low to high frequency power ratio were 81+/-13(58~110 beats/min), 791+/-1061(56~4161 msec2) and 1.08+/-1.22(0.04~4.85) during controlled respiration. After ice water application twenty three children developed 5 more nodal escape beats due to severe bradycardia. Minimum heart rate, high frequency power and low to high power ratio changed to 42+/-12(19~72/min), 1890+/-1882(221~7258msec2) and 0.64+/-0.43(0.12~1.46). The increased ratio of high frequency power, maximum heart rate decrement and its percent after stimulation were 5.44+/-5.62(0.63~24.26), 39+/-14(10~81/min) and 47+/-15(16~81%) respectively. The increased ratio of high frequency power was correlated with basal logarithmic high frequency power(r=-0.60, p=0.0004). Maximum heart rate decrement was correlated with basal logarithmic high frequency power(r=-0.41, p=0.0018) and low to high frequency power ratio(r=0.27, p=0.04). CONCLUSION: Application of ice water to the face during controlled respiration produces powerful vagal stimulation and bradycardia, however, there is a wide individual variability of responsiveness to it. The absolute basal vagal tone contribute to this individual variability.
Bradycardia ; Child ; Healthy Volunteers ; Heart Rate* ; Heart* ; Humans ; Ice* ; Respiration* ; United Nations ; Water*

PURPOSE: We investigated the autonomic nervous and complex modulation of heart rate and peripheral blood volume, and linear and nonlinear coupling between heart rate and peripheral blood volume in full-term and preterm infants. METHODS: In twenty healthy preterm infants and twenty full-term infants at postconceptional age of 30-37 and 38-41 weeks each, we recorded electrocardiogram and photoplethysmogram simultaneously during sleep in the supine position. To evaluate the autonomic and complex modulation, we performed power spectral analysis and analysis of the univariate nonlinear determinism. To quantify degree of linear and nonlinear couple between heart rates and peripheral blood volume, analyses of cross spectrum and bivariate nonlinear determinism were performed respectively. RESULTS: In the analysis of heart rates, preterm infants had significantly lower normalized high-frequency power (20.3+/-7.7% vs 30.7+/-15.1%, P<0.05), higher low-to high-frequency power ratio (3.0+/-2.1 vs 1.9+/-1.6, P<0.05), and significantly lower univariate prediction error (2.9+/-1.3% vs 4.1+/- 2.8%, P<0.05) when compared to full-term infants. In the analysis of peripheral blood volume, they showed no significant differences. Cross spectrum in all frequency ranges showed no significant difference between them. But preterm infants showed a significantly higher bivariate nonlinear prediction error (4.8+/-3.8% vs 3.1+/-2.2%, P<0.05) and a lower statistical coupling index (16.6+/-10.4 vs 22.9+/-9.2, P<0.05) than full-term infants. CONCLUSION: Compared to full-term infants, the heart rates of preterm infants are less modulated by cardiac parasympathetic activity and less complex. Furthermore, their peripheral blood volume was less nonlinearly coupled to heart rate.
Blood Volume* ; Electrocardiography ; Heart Rate* ; Heart* ; Humans ; Infant ; Infant, Newborn ; Infant, Premature* ; Nonlinear Dynamics ; Perfusion ; Supine Position

No abstract available.
Electric Stimulation* ; Epilepsy* ; Evoked Potentials*