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Pathophysiology of intraventricular electrical activation and its relation to cardiac resynchronization therapy
Sedláček, Kamil ; Wichterle, Dan (advisor) ; Linhart, Aleš (referee) ; Čurila, Karol (referee)
The QRS complex shortening by cardiac resynchronization therapy (CRT) has been associated with improved outcomes. We hypothesized that (1) the absence of QRS duration (QRSd) prolongation by right ventricular septal pacing may indicate a complete left bundle branch block (cLBBB), and (2) that the interval between the right-ventricular pacing stimulus and left-ventricular lead electrogram (RVP-LV) is a better predictor of the electrocardiographic effect of CRT than the interval Q-LV. We prospectively collected 12-lead surface ECG and intracardiac electrograms during CRT implant procedures. Digital ECG and intracardiac recordings were edited and manually measured. The outcome measure was the QRS duration change induced by CRT (deltaCRT). Several outcome predictors were investigated: native QRS duration (QRSd), cLBBB (as defined by Strauss), Q-LV and RVP-LV intervals, and a newly proposed index defined by the difference between the right-ventricle-paced QRSd and native QRSd (deltaRVP). We included 133 consecutive patients in the study and found that the baseline QRSd, deltaRVP, and Q-LV represent strong independent predictors of electrocardiographic response to CRT (deltaCRT). DeltaRVP correlates tightly with the CRT effect on QRSd and outperforms predictive value of the ECG-based cLBBB. Strong...
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Pathophysiological and clinical aspects of cardiac dyssynchrony in children and adolescents
Kovanda, Jan ; Janoušek, Jan (advisor) ; Bulava, Alan (referee) ; Klásková, Eva (referee)
Pathophysiological and clinical aspects of cardiac dyssynchrony in children and adolescents Electromechanical dyssynchrony is an important factor in the development of heart failure. It is caused by abnormal activation of the working myocardium in case of bundle branch block or ventricular pacing. Asymmetric hypertrophy of the affected ventricle develops together with its dilatation and reduced function and fulfils the picture of dyssynchronous cardiomyopathy. The development of dyssynchronopathy can be prevented by careful selection of the permanent pacing site and treated by cardiac resynchronization therapy. One of the aims of this work was to compare clinical and echocardiographic findings in patients paced from the left-ventricular apex with the healthy population. Using a retrospective cross-sectional study, we have proved that left ventricular function is not adversely affected in long-term follow-up. Another aim of the study was to evaluate the long-term results of resynchronization therapy of the systemic ventricle in patients with congenital heart defects. Using a retrospective study, we have described an acceptable long-term survival at the price of relatively frequent complications. We were extensively working on a new method of resynchronization of the right subpulmonary ventricle in...
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Neuromodulation in heart failure
Naar, Jan ; Ošťádal, Petr (advisor) ; Rokyta, Richard (referee) ; Vízek, Martin (referee)
The prognosis of heart failure with reduced ejection fraction remains poor. Neurohumoral activation, including increased cardiac sympathetic nerve activity, plays an important role in the pathogenesis as well as disease progression. Recently, several neuromodulation strategies have been proposed that aim to directly affect the residual autonomic imbalance. Spinal cord stimulation is one of the proposed methods. In the clinical part of this project, we assessed the mid-term effect of spinal cord stimulation on cardiac sympathetic nerve activity and the acute effect on autonomic balance. In the total study population, we did not detect any changes in cardiac sympathetic nerve activity or heart rate variability. However, we observed that the patients with high baseline sympathetic nerve activity or low heart rate variability responded favourably to therapy, reflected in reduced cardiac sympathetic nerve activity and increased heart rate variability. Considering these results, we conducted an experimental study focused on the effect of acute severe heart failure on heart rate variability. In a porcine model of hypoxic myocardial dysfunction, we observed a significant reduction in heart rate variability in all parameters recorded. Our results indicate that spinal cord stimulation may improve autonomic...
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Role of echocardiography in cardiac resynchronization therapy
Marek, Josef ; Linhart, Aleš (advisor) ; Mandysová, Eva (referee) ; Ozábalová, Eva (referee)
Cardiac resynchronization therapy (CRT) is an established treatment of patients with heart failure with reduced ejection fraction associated with QRS complex prolongation. However, about 30% of patients do not respond to CRT favorably, more so patients with shorter QRS duration and QRS morphology other than typical left bundle branch block. Echocardiography plays a crucial role in management of all those patients. Echocardiographic assessment of myocardial mechanics can quantitate myocardial deformation and find myocardial segments that are latest mechanically activated in a dyssynchronously contracting left ventricle. Left ventricular (LV) lead placement in this area is associated with clinical response to CRT. On the other hand, lead placement within a scar has been associated with bad prognosis. The aim of this work was to investigate whether left ventricular lead placed close to the site of latest mechanical activation is beneficial especially in patients with shorter QRS durations or atypical QRS morphology. This has been done by analyzing data of the randomized trial STARTER, which compared echo-guided LV lead navigation to routine empirical lead placement. The STARTER trial proved clinical benefit of echo-guided LV lead placement towards the site of latest mechanical activation. In our...
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Analysis of the acute effect of cardiac resynchronization therapy on electrocardiogram
Holík, Jiří ; Vítek, Martin (referee) ; Pospíšil,, David (advisor)
This bachelor thesis deals with the non-pharmacological treatment of symptomatic heart failure, specifically cardiac resynchronization therapy. The introductory research develops the topic as a whole and prepares the author and the reader for the subsequent practical part. The latter focuses on the analysis of selected parameters that undergo acute change after pacemaker implantation. According to the instructions of the assignment, a functional pilot software for QRS complex detection, heart rate calculation and QRS complex dimensioning for some leads has been implemented. Furthermore, the heart rate variability in the frequency domain is analysed and the results are tabulated.
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Pharmacological possibilities for amending renal dysfunction in experimental model of heart failure
Krátký, Vojtěch ; Charvátová, Zuzana (advisor) ; Bednářová, Vladimíra (referee) ; Melenovský, Vojtěch (referee)
Mechanisms underlying the development of renal dysfunction and pharmacological possibilities for its amending in patients with chronic heart failure are still incompletely understood. The aim of the study was thus to compare the effect of treatment with an ACE inhibitor (ACEi), AT1 receptor blocker (ARB) or combined angiotensin receptor-neprilysin inhibitor (ARNi) on renal hemodynamic and excretory functions in experimental models of heart failure induced by placing an aorto-caval fistula (ACF) in combination with hypertension or preexisting renal disease. In normotensive and especially in hypertensive rats with high- output heart failure 20 weeks after ACF placement, ARB administration, dissimilarly to an ACEi treatment, was shown to prevent renal hypoperfusion and hypoxia. In addition, heart failure rats treated with ARB exhibited lower ROS generation, improved renal NO bioavailability, and normal renal SNS activity. The failure of ACEi to ameliorate renal hypoperfusion in rats with heart failure may be a consequence of insufficiently suppressed intrarenal RAS along with enhanced renal SNS activity in the face of depleted compensatory mechanisms, namely NO. Combined ARNi treatment in rats with induced heart failure superimposed on progressive renal dysfunction significantly improved survival...
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Study of the effect of myocardial fibrosis on elemental distribution in rat soft tissues using Laser Ablation ICP-MS
Machalová, Martina ; Zlámalová Gargošová, Helena (referee) ; Vašinová Galiová, Michaela (advisor)
The most common cause of death in the Czech Republic continue to be cardiovascular diseases. The field of heart failure therapy still keeps moving forward. Yet myocardial fibrosis is one of the consequences and causes of heart failure for which there exists no effective medical care. The solution would be predicting the advancement of fibrosis and a preventive therapy. Many medical methods are being developed now in this regard, and the element distribution in affected tissue could help them. That is the reason why this work centers on the research of the element distribution in rat hearts with an induced myocardial fibrosis. An influence of sample couloration on the analysis was observed during its course. Special attention was paid to the distribution of iron in the fibrotic tissue as well as to the comparisson of the images of myocardial fibrosis. It seems that the iron distribution specificly could be helpful in recognising a damaged myocardium.
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The role of Arachidonic acid metabolites in cardiovascular system and signaling of heart failure
Liptáková, Andrea ; Žurmanová, Jitka (advisor) ; Holzerová, Kristýna (referee)
Arachidonic acid (AA) is polyunsaturated acid that plays an important role in regulation of physiology, bioenergetic and signalling cascades in the heart. AA released by phospholipase A2-catalysed hydrolysis of membrane phospholipids serves as substrate for cyclooxygenase, lipooxygenase and cytochrome P450 epoxygenase to produce a wide spectrum of lipid second messengers, eicosanoids. These very biologically potent molecules regulate a number of cellular processes in the cardiovascular system and changes in their composition and concentration significantly contribute to heart failure. The aim of this thesis was to summarize current knowledge about the role of AA in failing heart. Keywords : Heart, Arachidonic Acid, Heart Failure, Eicosanoids, Cardiovascular System
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Education of patients with left ventricular assist device HeartMateII
Brejchová, Eliška ; Kulhavá, Miluše (advisor) ; Sentivanová, Lenka (referee)
The thesis discusses the education of patients with left ventricular support HeartMate II. Theoretical part is focused on education and its ethical and legal aspects, on the description of the educational process. Furthermore it focuses on heart supports, especially on left ventricular assist device HeartMate II. To provide a comprehensive overview, I have included also information about the anatomy and physiology of the cardiovascular system and the section on heart failure. I described the specifics of nursing care for patients with implanted HeartMate II system and the educational topics that should be part of the education of these patients. The empirical part was prepared as a quantitative research, where research sample was 47 respondents. Respondents consisted of nurses who educate patients after implantation of the HeartMate II at the cardiovascular surgical intensive care unit. To create the feedback I complemented a quantitative research with structured interviews with patients after implantation of the HeartMate II. The aim of the research was to determine the status and range of education of patients with left ventricular assist device HeartMate II. This thesis further maps the topics on which is placed the emphasis in education and vice versa topics that would need to focus more on....
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Pathophysiological consequences of different cardiac support regimens in cardiorespiratory insufficiency
Lacko, Stanislav ; Kittnar, Otomar (advisor) ; Havránek, Štěpán (referee) ; Rohn, Vilém (referee)
Introduction: Veno-arterial extracorporeal membrane oxygenation (VA ECMO) is a rapidly applicable type of mechanical circulatory support that overcomes acute hemodynamic breakdowns, whether in acute or chronic heart failure or cardiac arrest. In recent years, the method has seen a very significant increase in use. VA ECMO can fully replace the function of the heart and lungs, delivering about 5 l / min of fully saturated blood. However, the method is burdened with a number of risks. Currently much-discussed issue is the effect of circulatory support on left ventricular residual function as VA ECMO increases its work and the risk of developing left ventricular distension and subsequent pulmonary edema. A detailed analysis of these pathophysiological mechanisms is a key objective of this work. Methods: The focus of the work is three series of experiments on a large biomodel (domestic pig). First, we developed a new model of acute hypoxic-ischemic heart failure by proximal occlusion of one of the main branches of the left coronary artery with a balloon catheter with a lumen for controlled perfusion of deoxygenated venous blood behind the balloon. Furthermore, we monitored the hemodynamic response and energy parameters in detail in the porcine biomodel of acute and chronic heart failure with a gradual...
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