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The contribution subscribes a numerical simulation of a steam flow through a balanced control valve. The influence of some parameters in simulations were tested, analyzed and discussed. As a result of the simulations a graph of aerodynamics forces for a specific turbine characteristic was obtained. The results from numerical simulations were compared with results from experiments. The experiment was performed with an air flow, but the final data were converted with a criterion to steam flow.

The objective of our study was to compare the cellular and extracellular matrix (ECM) structure and the biomechanical properties of human pericardium (HP) with the normal human aortic heart valve (NAV). HP tissues (from 12 patients) and NAV samples (from 5 patients) were harvested during heart surgery. The main cells in HP were pericardial interstitial cells, which are fibroblast-like cells of mesenchymal origin similar to the valvular interstitial cells in NAV tissue. The ECM of HP had a statistically significantly (p < 0.001) higher collagen I content, a lower collagen III and elastin content, and a similar glycosaminoglycans (GAGs) content, in comparison with the NAV, as measured by ECM integrated density. However, the relative thickness of the main load-bearing structures of the two tissues, the dense part of fibrous HP (49 ± 2%) and the lamina fibrosa of NAV (47 ± 4%), was similar. In both tissues, the secant elastic modulus (Es) was significantly lower in the transversal direction (p < 0.05) than in the longitudinal direction. This proved that both tissues were anisotropic. No statistically significant differences in UTS (ultimate tensile strength) values and in calculated bending stiffness values in the longitudinal or transversal direction were found between HP and NAV. Our study confirms that HP has an advantageous ECM biopolymeric structure and has the biomechanical properties required for a tissue from which an autologous heart valve replacement may be constructed.

Objective: To evaluate systolic dyssynchrony index (SDI) measured by real time three-dimensional echocardiography (RT3DE) and Doppler tissue imaging (DTI) dyssynchrony parameters in predicting the hemodynamic response to biventricular (BIV) pacing in the early postoperative period after cardiac surgery. To compare right ventricular (RV) and BIV pacing using invasively measured hemodynamic values., Methods: A prospective randomized clinical study enrolling 11 patients with ischemic heart disease, concomitant valvular heart disease, and left ventricular ejection fraction (LVEF) ≤ 35% comparing preoperative SDI by RT3DE and DTI LV dyssynchrony parameters to hemodynamic values obtained during RV or BIV sequential (DDD) epicardial pacing in the first 72 hours after cardiac surgery., Results: BIV pacing produced a statistically significant higher cardiac output (CO) (6.27 ± 1.55 L/min) and cardiac index (CI) (3.44 ± 0.93 L/min per m(2) ) than RV pacing (CO 5.44 ± 0.97 L/min, CI 3.03 ± 0.83 L/min per m(2) , P < 0.05). We found a statistically moderate correlation between preoperative SDI by RT3DE and CO (r = 0.596, P < 0.05) and a nonsignificant correlation to CI (r = 0.535, P < 0.10) during BIV pacing. No correlation was observed between DTI dyssynchrony parameters and measured hemodynamic values. BIV pacing reduced the ICU stay and inotropic support requirements of patients after heart surgery., Conclusions: SDI measured preoperatively using RT3DE can predict CO during BIV pacing in the early postoperative period after cardiac surgery. BIV pacing is more hemodynamically effective than RV pacing in patients with LV dysfunction after coronary artery bypass grafting with or without a valve procedure., (© 2012, Wiley Periodicals, Inc.)

Background: Congestive heart failure negatively impacts the prognosis in patients after cardiac surgery. The aim of our study was to assess the value of targeted cardiac resynchronization therapy (CRT) within 72 hours after cardiac surgery in patients with mechanical dyssynchrony, who had an ejection fraction ≤ 35%, QRS ≥150 ms or between 120 and 150 ms., Methods: A prospective randomized trial based on three-dimensional echocardiography (RT3DE) and optimized sequential dual-chamber (DDD ) pacing in patients after cardiac surgery. DDD epicardial pacing (Medtronic coaxial epicardial leads 6495) was provided by a modified Medtronic INSYNC III Pacemaker (Medtronic Inc., Minneapolis, MN, USA)., Summary of Results: The study included 21 patients with ischemic heart disease (HD) or valvular HD (16 men, 5 women, average age 69 years) with left ventricle (LV) dysfunction after cardiac surgery . Patients with biventricular (BIV) (CO 6.7 ± 1.7 L/min, CI 3.5 ± 0.8 L/min/m(2) ) and LV (CO 6.2 ± 1.5 L/min, CI 3.2 ± 0.7 L/min/m(2) ) pacing had statistically significantly higher CO and CI than patients with right ventricular (RV) (CO 5.4 ± 1.4 L/min, CI 2.8 ± 0.6 L/min/m(2) ) pacing (BIV vs RV P ≤ 0.001; LV vs RV P ≤ 0.05; BIV vs LV P ≤ 0.05)., Conclusions: RT3DE targeted and optimized CRT in the early postperative period after cardiac surgery provided better hemodynamic results than RV pacing. , (©2011, The Authors. Journal compilation ©2011 Wiley Periodicals, Inc.)

Coronary artery lesions are evaluated in a group of 43 patients surviving for more than 3 months after heart transplantation. An angiographic finding was obtained from 35 patients, autopsy findings were available in eight cases. Angiography demonstrated coronary artery lesions in 12 out of the 35 patients whereas autopsy findings were positive in five out of the eight post mortem examinations. Overall, lesions were found in 40% of patients at a mean follow-up interval of 3.5 years. While the finding of a coronary artery lesion was not related to the classic risk factors for atherosclerosis, an association to a previous cytomegalovirus or Epstein-Barr virus infection was demonstrated. The data suggest that infection caused by the two above viruses is an important factor in the development of vascular lesions in the heart transplant.

During the period from 1984-1991 in the Institute of Clinical and Experimental Medicine 72 orthotopic transplantations of the heart were performed in 71 patients with irreversible cardiac failure. Indication for transplantation in 39 patients was IHD, in 28 cardiomyopathy, in 3 RHD and in one instance a tumour. The mean age of the patients was 41 years, the youngest patient was 17 and the oldest 62 years old. Immunosuppression involved a combination of three preparations Azathioprine, corticoids and Cyclosporine A. Nineteen patients died within one month after operation. The most frequent cause of death was cardiac failure. As to postoperative complications, renal failure was most frequent. Fifty patients were followed-up on a long-term basis. The longest survival period was 8 years and 2 months. The most frequent cause of death in the long-term follow-up was sudden death caused in the majority most probably by rapid development of coronary disease.