Ventricular function and ventriculo-arterial coupling after palliation of hypoplastic left heart syndrome: A comparative study with Fontan patients with LV morphology.

BACKGROUND: Conceptually the right ventricle (RV) is less suitable to support the Fontan circulation than the left (LV). After palliation of hypoplastic left heart syndrome (HLHS) involving aortic reconstruction during the Norwood procedure the RV is exposed to abnormal afterload. We studied ventricular function and ventriculo-arterial coupling in HLHS patients (RV) and Fontan patients with single LV morphology that did (LV+N) and did not (LV-N) undergo Norwood-type aortic reconstruction. METHODS: Eighty patients (55 RV, 8 LV+N, 17 LV- N) were simultaneously studied with the conductance-catheter and echocardiography 4.8 (0.9-22.9)years after Fontan completion. RESULTS: Ejection fraction (EF) was lowest in the HLHS group (RV 60.9±11.0 vs. LV+N 68.4±10.5 vs. LV-N 69.7±8.0, P=0.003) whereas end systolic elastance (Ees), i.e. ventricular contractility, and end diastolic stiffness (Eed) were highest (Ees: RV 3.38±2.2 vs. LV+N 2.3.±13.8 vs. LV-N 1.92±1.37mmHg/ml, P=0.02; Eed: RV 0.59±0.36 vs. LV+N 0.48±0.29 vs. LV-N 0.32±0.17mmHg/ml, P<0.02). Arterial elastance, a measure of afterload, was highest in HLHS patients and correlated positively with Ees and Eed and inversely with EF in the study cohort. Only long axis function analysis suggested superior ventricular function in HLHS patients whereas all other echocardiographic measures did not reveal any group differences. CONCLUSION: Ventricular contractility of the RV of HLHS patients is higher than that of the ventricle of Fontan patients with LV morphology. This likely reflects a physiological response to higher arterial elastance resulting from aortic arch reconstruction. Increased arterial elastance negatively impacts diastolic stiffness, which is higher in the systemic RV than LV.

SAW devices for consumer communication applications.

An overview of surface acoustic wave (SAW) filter techniques available for different applications is given. Techniques for TV IF applications are outlined, and typical structures are presented. This is followed by a discussion of applications for SAW resonators. Low-loss devices for mobile communication systems and pager applications are examined. Tapped delay lines (matched filters) and convolvers for code-division multiaccess (CDMA) systems are also covered. Although simulation procedures are not considered, for many devices the theoretical frequency response is presented along with the measurement curve.

Modular two-dimensional analysis of SAW filters. II. Analysis and compensation results.

For pt.I see ibid vol.39, no.1, pp.61-72 (1992). Physical effects causing distortions of the transfer function of a broadband (36% fractional bandwidth) spectrum shaping filter for digital radio with 16 quadrature amplitude modulation (QAM) are analyzed separately and connected with the modular two-dimensional (2-D) model described in Part I, demonstrating the importance of every single effect. A compensation of the second-order effects is performed, yielding an agreement between simulation and measurement in amplitude and phase of more than +/-0.1 dB and +/-1 degrees all over the passband. The stopband is also predicted with high accuracy.

Spectrum shaping SAW filters for high-bit-rate digital radio.

The structure of a QAM radio system is explained. Some novel designs that demonstrate the current status of spectral shaping SAW (surface acoustic wave) filters are presented. Compensation of second-order effects is discussed. Experimental results for a filter for a 140-Mb/s 16 QAM cochannel system with a roll-off factor of 0.19 are shown. Two other examples of filters for a 140-Mb/s, 64 QAM system with a 35% relative bandwidth are also presented.

[Improvement of the flow properties of the blood of patients by low-molecular hydroxyethyl starch (Expafusin)]. / Verbesserung der Fliesseigenschaften des Blutes von Patienten durch niedermolekulare Hydroxyäthylstärke (Expafusin).

10 patients with various diseases causing elevated ESR-values and impaired flow properties of blood received infusions of 500 ml of low molecular weight hydroxyethylstarch (HES 6%, Expafusin) within approximately 30 minutes. Measurements of rheological parameters for several hours after infusion showed a statistically significant decrease of apparent whole blood viscosity and of plasma viscosity. RBC aggregation was slightly, but statistically significantly reduced, whereas RBC filterability remained unchanged. These data obtained with blood from patients with altered flow properties of blood agree very well with former results obtained in healthy volunteers.