Forsøksdyr: Methods for Measuring Cardiac Function Using Electromagnetic Tracking

Godkjenningsdato 03.10.2018

Godkjenningsperiode 22.10.2018-21.10.2020

Left bundle branch block (LBBB) is a cardiac conduction abnormality where the different walls of the left ventricle are electrically stimulated and contract at different times (dyssynchrony). This condition often results in a reduction in pump function which can end up developing or worsening heart failure (HF). This condition can be treated with cardiac resynchronization therapy (CRT), which is a medical device that resynchronizes the ventricles contraction with the atrial activation by sending electric impulses to the heart muscle. However, the response varies strongly among patients and approximately 30-40 percent of them do not benefit from this therapy. One reason for poor response in some of the patients, may be that the pacing electrodes are not placed in the correct position.

The hypothesis presented in this study is that ventricular dyssynchrony can be measured by placing motion sensors on the heart, and that evaluation of the heart motion can be used to evaluate optimal implantation and settings for CRT.

Based on data from previous similar trials, a total of 15 experiments are planned. The trials require extensive instrumentation of the heart and they will therefore be performed as acute, terminal attempts. During experiments physiological measurements will be registered at different intervals during the interventions. Studies have shown that canines have most similar electrical conduction system to humans and therefore represent a good experimental model for LBBB, while for example porcines have a different purkinje system so they do not exhibit the same degree of dyssynchrony. Furthermore, canines tolerate the prolonged instrumentation without serious complications during the experiment, as opposed to porcines that have higher mortality. The number of animals is reduced by collecting data for multiple studies at the same time without any significant increased risk of failed attempts. Furthermore, the sensors are tested in virtual and robot models prior to animal testing. This reduces the chances of failed experiments due to technical problems or mistakes that were discovered prior to animal testing.