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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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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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Studium of the clinical impact of different forms of cardiac resynchronisation therapy by patients with chronic heart failure
Burianová, Lucie ; Kautzner, Josef (advisor) ; Janoušek, Jan (referee) ; Táborský, Miloš (referee)
Studium of the clinical impact of different forms of cardiac resynchronization therapy by patients with chronic heart failure MUDr. Lucie Burianová ABSTRACT: Introduction: Biventricular (BiV) pacing decreases mortality and improves quality of life of patients with severe heart failure. Haemodynamic and short time clinical studies suggest that isolated leftventricular pacing could have the same effect. Aims: Compare the effect of BiV and leftventricular pacing by subjects with dilated cardiomyopathy and severe heart failure with the attention to signs of dyssynchrony and remodelation of the left chamber. In methodical substudy compare the results of left chamber volumes and ejection fraction (EF LK) measured by CT angiography and 2-dimensional echocardiography with use of contrast agent (K-ECHO). Methods: Patients indicated for cardiac resynchronization therapy were randomized for either BiV or leftventricular pacing. After implantation of the device they were examinated clinically and by echocardiography every 3 months in the period of one year. Four years from the onset of the study the major adverse events in both groups were evaluated. The results of left chamber volumes and EF LK measured by K-ECHO and CT angiography were compared. Results: We enrolled 33 patients. We found clinical improvement in both...
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Studium of the clinical impact of different forms of cardiac resynchronisation therapy by patients with chronic heart failure
Burianová, Lucie ; Kautzner, Josef (advisor) ; Janoušek, Jan (referee) ; Táborský, Miloš (referee)
Studium of the clinical impact of different forms of cardiac resynchronization therapy by patients with chronic heart failure MUDr. Lucie Burianová ABSTRACT: Introduction: Biventricular (BiV) pacing decreases mortality and improves quality of life of patients with severe heart failure. Haemodynamic and short time clinical studies suggest that isolated leftventricular pacing could have the same effect. Aims: Compare the effect of BiV and leftventricular pacing by subjects with dilated cardiomyopathy and severe heart failure with the attention to signs of dyssynchrony and remodelation of the left chamber. In methodical substudy compare the results of left chamber volumes and ejection fraction (EF LK) measured by CT angiography and 2-dimensional echocardiography with use of contrast agent (K-ECHO). Methods: Patients indicated for cardiac resynchronization therapy were randomized for either BiV or leftventricular pacing. After implantation of the device they were examinated clinically and by echocardiography every 3 months in the period of one year. Four years from the onset of the study the major adverse events in both groups were evaluated. The results of left chamber volumes and EF LK measured by K-ECHO and CT angiography were compared. Results: We enrolled 33 patients. We found clinical improvement in both...
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