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Figure 1 Baseline duration of QRS (white bars), interventricular delay (black bars), and posterolateral left ventricular wall activation delay (striped bars) in patients in group 1 with sinus rhythm (SR) at enrollment, with prior pacemaker implantation (PM), and in group 2. The only difference between the groups is represented by QRS duration (*p < 0.001 group 2 vs. RS and vs. PM).