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2. Hemodynamic adaptation of heart failure to percutaneous venoarterial extracorporeal circulatory supports

Creator:
Hála, Pavel and Kittnar, Otomar
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
extrakorporální membránová oxygenace, srdeční selhání, hemodynamika, extracorporeal membrane oxygenation, heart failure, hemodynamics, ventricular overload, perfusion, 14, and 612
Language:
English
Description:
Extracorporeal life support (ECLS) is a treatment modality that provides prolonged blood circulation, gas exchange and can partially support or fully substitute functions of heart and lungs in patients with severe but potentially reversible cardiopulmonary failure refractory to conventional therapy. Due to high-volume bypass, the extracorporeal flow is interacting with native cardiac output. The pathophysiology of circulation and ECLS support reveals significant effects on arterial pressure waveforms, cardiac hemodynamics, and myocardial perfusion. Moreover, it is still subject of research, whether increasing stroke work caused by the extracorporeal flow is accompanied by adequate myocardial oxygen supply. The left ventricular (LV) pressure-volume mechanics are reflecting perfusion and loading conditions and these changes are dependent on the degree of the extracorporeal blood flow. By increasing the afterload, artificial circulation puts higher demands on heart work with increasing myocardial oxygen consumption. Further, this can lead to LV distention, pulmonary edema, and progression of heart failure. Multiple methods of LV decompression (atrial septostomy, active venting, intra-aortic balloon pump, pulsatility of flow) have been suggested to relieve LV overload but the main risk factors still remain unclear. In this context, it has been recommended to keep the rate of circulatory support as low as possible. Also, utilization of detailed hemodynamic monitoring has been suggested in order to avoid possible harm from excessive extracorporeal flow., Pavel Hála, Otomar Kittnar., and Obsahuje bibliografii
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

3. Increasing veno-arterial extracorporeal membrane oxygenation flow reduces electrical impedance of the lung regions in porcine acute heart failure

Creator:
Popková, Michaela, Kuriščák, Eduard, Hála, Pavel, Janák, David, Tejkl, Leoš, Bělohlávek, Jan, Ošťádal, Petr, Neužil, Petr, Kittnar, Otomar, and Mlček, Mikuláš
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
extrakorporální membránová oxygenace, elektrická impedanční tomografie, extracorporeal membrane oxygenation, electrical impedance tomography, pulmonary edema, swine, 14, and 612
Language:
English
Description:
Veno-arterial extracorporeal membrane oxygenation (VA ECMO) is a technique used in patients with severe heart failure. The aim of this study was to evaluate its effects on left ventricular afterload and fluid accumulation in lungs with electrical impedance tomography (EIT). In eight swine, incremental increases of extracorporeal blood flow (EBF) were applied before and after the induction of ischemic heart failure. Hemodynamic parameters were continuously recorded and computational analysis of EIT was used to determine lung fluid accumulation. With an increase in EBF from 1 to 4 l/min in acute heart failure the associated increase of arterial pressure (raised by 44 %) was accompanied with significant decrease of electrical impedance of lung regions. Increasing EBF in healthy circulation did not cause lung impedance changes. Our findings indicate that in severe heart failure EIT may reflect fluid accumulation in lungs due to increasing EBF., Michaela Popková, Eduard Kuriščák, Pavel Hála, David Janák, Leoš Tejkl, Jan Bělohlávek, Petr Ošťádal, Petr Neužil, Otomar Kittnar, Mikuláš Mlček., and Obsahuje bibliografii
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

4. Selected sex related differences in pathophysiology of cardiovascular system

Creator:
Kittnar, Otomar
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
sex related differences, cardiovascular system, and sex hormones
Language:
English
Description:
The annual incidence of cardiovascular diseases is agedependently increasing both in men and women, however, the prevalence is higher in men until midlife. The higher incidence of cardiovascular disease in men than in women of similar age, and the menopause-associated increase in cardiovascular disease in women, has led to speculation that gender-related differences in sex hormones might have a key role in the development and evolution of cardiovascular disease. There are several suggested pathways in which gender and sex hormones can affect human cardiovascular system to produce original sexually different pathophysiology between women and men. Sex steroid hormones and their receptors are critical determinants of cardiovascular gender differences. Also arterial blood pressure is typically lower in women than in men what could be explained particularly by greater synthesis of nitric oxide (NO) in women. Female cardiomyocytes have a greater survival advantage when challenged with oxidative stress, suggesting that female hormones may play an important role in antioxidative protection of myocardium. It was also demonstrated in animal models that combination of XX chromosomes versus an XY chromosomes enhances sex differences in higher HDL cholesterol. Women were found to have reduced sympathetic activity (reflected by lower total peripheral resistance) and pulmonary artery pressure and enhanced parasympathetic activity relative to men. Similarly, men were found to have higher plasma norepinephrine levels than women. Regarding differences between the sexes in electrophysiology of the heart, two principle mechanisms have been proposed to explain them: hormonal effects on the expression or function of ion channels or, conversely, differences in autonomic tone. To improve diagnosis and treatment of cardiovascular diseases, greater focus on understanding the molecular and cellular physiology of the sex steroid hormones and their receptors in the cardiovascular system will be required.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

5. Stručná fyziologie a patofyziologie smyslů

Creator:
Kittnar, Otomar
Type:
model:article, article, Text, and TEXT
Subject:
smyslové orgány--fyziologie, somatosenzorické korové centrum, mozková kůra, nervový přenos, sluchové dráhy--fyziologie, zrakové dráhy--fyziologie, vestibulární aparát--fyziologie, chuť--genetika, čichové dráhy--fyziologie, and lidé
Language:
Czech and English
Description:
Jsou probrány smyslové orgány jako systémy sloužící detekci informací ze zevního i vnitřního prostředí a jejich předání do centrálního nervového systému, kde jsou pak zpracovávány za účasti řady mozkových struktur tak, aby mohly být podkladem vědomé interpretace okolního světa. Jsou zmíněny smyslové receptory jako nervové struktury zaznamenávající specifické formy energie v našem okolí a jejich klíčová funkce, tzv. transdukce, tj. přeměna energie dané modality na elektrickou energii akčních potenciálu aferentních nervů. Informace zakódovaná v této podobě je pak přepojována v podkorových ? talamických centrech a zpracována a syntetizována v mozkové kůře. Konkrétní uspořádání tohoto obecného schématu je uvedeno pro jednotlivé hlavní smyslové systémy: somatosenzorický, zrakový, sluchový, vestibulární, chuťový a čichový. Stručně jsou probrány také základní poruchy smyslového vnímání, jejich obecná etiologie a patogenetické mechanismy, zodpovědné za jejich vývoj a příznaky. and Otomar Kittnar
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

6. Ten years of our translational research in the field of veno-arterial extracorporeal membrane oxygenation

Creator:
Kittnar, Otomar
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
translational medicine, extracorporeal life support, VA ECMO, and heart failure
Language:
English
Description:
Extracorporeal life support is a treatment modality that provides prolonged blood circulation, gas exchange and can substitute functions of heart and lungs to provide urgent cardio-respiratory stabilization in patients with severe but potentially reversible cardiopulmonary failure refractory to conventional therapy. Generally, the therapy targets blood pressure, volume status, and end-organs perfusion. As there are significant differences in hemodynamic efficacy among different percutaneous circulatory support systems, it should be carefully considered when selecting the most appropriate circulatory support for specific medical conditions in individual patients. Despite severe metabolic and hemodynamic deterioration during prolonged cardiac arrest, venoarterial extracorporeal membrane oxygenation (VA ECMO) can rapidly revert otherwise fatal prognosis, thus carrying a potential for improvement in survival rate, which can be even improved by introduction of mild therapeutic hypothermia. In order to allow a rapid transfer of knowledge to clinical medicine two porcine models were developed for studying efficiency of the VA ECMO in treatments of acute cardiogenic shock and progressive chronic heart failure. These models allowed also an intensive research of adverse events accompanying a clinical use of VA ECMO and their possible compensations. The results indicated that in order to weaken the negative effects of increased afterload on the left ventricular function the optimal VA ECMO flow in cardiogenic shock should be as low as possible to allow adequate tissue perfusion. The left ventricle can be also unloaded by an ECG-synchronized pulsatile flow if using a novel pulsatile ECMO system. Thus, pulsatility of VA ECMO flow may improve coronary perfusion even under conditions of high ECMO blood flows. And last but not least, also the percutaneous balloon atrial septostomy is a very perspective method how to passively decompress overloaded left heart.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public