In this paper, lumped-parameter models of the cardiovascular system, the cardiac electrical conduction system and a pacemaker are coupled to generate mitral flow profiles for different atrio-ventricular delay (AVD) configurations, in the context of cardiac resynchronization therapy (CRT). First, we perform a local sensitivity analysis of left ventricular and left atrial parameters on mitral flow characteristics, namely E and A wave amplitude, mitral flow duration, and mitral flow time integral. Additionally, a global sensitivity analysis over all model parameters is presented to screen for the most relevant parameters that affect the same mitral flow characteristics. Results provide insight on the influence of left ventricle and atrium influence on mitral flow profiles. This information will be useful for future parameter estimation of the model that could reproduce the mitral flow profiles and cardiovascular hemodynamics of patients undergoing AVD optimization during CRT.