Rick Schreurs

138 Chapter 7 data for developing a dog-specific computer model. Now this has been developed, studies may be performed in this model instead of animals. CONCLUSION Based on this thesis we can conclude that restoration of AV-coupling using BiV pacing in heart failure patients and pigs with first degree AV-block leads to significant improvements of LV hemodynamics, based on optimal ventricular filling due to an increase in forward flow and a decrease in diastolic mitral regurgitation. This may lead to a novel pacing-based therapeutic option in patients with heart failure and prolonged PR-interval. Furthermore, this suggests that AV-delay optimization remains an important factor in improving efficacy of pacemaker therapies like CRT. While optimizing the AV-delay one should not only focus on the left side of the heart, but also pay attention to the right side. Additionally, as the optimal AV-delay is influenced by interatrial delay and interventricular dyssynchrony, the mean effective AV-delay could be a new parameter for AV-delay optimization. Ultimately, ambulatory optimization of programmed AV-delays should focus on left and right sided AV-delays and make use of a combination of electrical and mechanical parameters.