QRS elongation after radiofrequency application-induced left bundle branch block

<p>Surface electrocardiogram and annotated QRS duration in four distinct animals at baseline (first line), after left bundle branch block (LBBB, middle line), and 4 weeks after LBBB at the endpoint (EP) of the study (botom line). Colored values represent percentage increase in QRS duration and are coded according to the level of significance (red = minimal QRS elongation, orange = mild QRS elongation, green = optimal QRS elongation, &gt;50%).</p>