<p>Knowledge of the leftventricular (LV) pressure-volume relation, along withparameters derived from this relation, have led to newpossibilities for the characterisation of cardiac pumpfunction, in both experimental studies and clinicalsettings.</p><p>The pressure-volume diagram is apowerful tool for visualising LV performance, but in order tobe clinically useful it is necessary to make plots continuouslyand on-line. The conductance catheter technique offers thispossibility. The conductance catheter system has experiencedgrowing interest among cardiologists, physiologists, surgeons,and anaesthesiologists around the world as a powerful newresearch tool, but the invasiveness of this technique has beena limiting factor for most clinical applications. The catheterneeds to be thinner and softer in order to make this techniquemore suitable for human use.</p><p>This thesis reports of a newthin and soft conductance catheter for continuously and on-linemeasurements of LV pressure and volume.</p><p>One way to reduce both cathetersize and stiffness is to decrease the number of electrodes onthe catheter. Theoretical calculations shown in this thesisproves that it is possible to obtain the same performance witha single segment catheter as with a five-segment catheter. Thethin catheter has been tested and compared to a commercialfive-segment conductance catheter in animal studies.</p><p>We conclude that the thin singlesegment conductance catheter can measure left ventricularvolume and pessure. The regression coefficient between the twomethods is good independent of loading condition and duringbaseline conditions the catheters produce very similar volumecurves. During preload reduction the estimated volume reductionis different in the two systems.</p><p>Our thin catheter does notdisturb the heart's normal electrophysiology, neither by thecatheter current nor by any mechanical stimuli. The resultsdemonstrates that our thin, soft, single segment conductancecatheter has performance characteristics which warrant furtherdevelopment, with the goal to make the method available forhuman use.</p>

Knowledge of the leftventricular (LV) pressure-volume relation, along withparameters derived from this relation, have led to newpossibilities for the characterisation of cardiac pumpfunction, in both experimental studies and clinicalsettings. The pressure-volume diagram is apowerful tool for visualising LV performance, but in order tobe clinically useful it is necessary to make plots continuouslyand on-line. The conductance catheter technique offers thispossibility. The conductance catheter system has experiencedgrowing interest among cardiologists, physiologists, surgeons,and anaesthesiologists around the world as a powerful newresearch tool, but the invasiveness of this technique has beena limiting factor for most clinical applications. The catheterneeds to be thinner and softer in order to make this techniquemore suitable for human use. This thesis reports of a newthin and soft conductance catheter for continuously and on-linemeasurements of LV pressure and volume. One way to reduce both cathetersize and stiffness is to decrease the number of electrodes onthe catheter. Theoretical calculations shown in this thesisproves that it is possible to obtain the same performance witha single segment catheter as with a five-segment catheter. Thethin catheter has been tested and compared to a commercialfive-segment conductance catheter in animal studies. We conclude that the thin singlesegment conductance catheter can measure left ventricularvolume and pessure. The regression coefficient between the twomethods is good independent of loading condition and duringbaseline conditions the catheters produce very similar volumecurves. During preload reduction the estimated volume reductionis different in the two systems. Our thin catheter does notdisturb the heart's normal electrophysiology, neither by thecatheter current nor by any mechanical stimuli. The resultsdemonstrates that our thin, soft, single segment conductancecatheter has performance characteristics which warrant furtherdevelopment, with the goal to make the method available forhuman use. / NR 20140805

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...

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...