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Figure 3 Managed Ventricular Pacing

For pacing facilitated S-L-S, a VPD (600-ms interval, asterisk) ("short") occurs almost simultaneously with an atrial pace (AP) (800-ms interval). The VPD is marked as a sensed event but, because it falls in the 80-ms cross-talk window, is not considered a true ventricular event. The next AP (800 ms) fulfills the criteria for an A-A interval without an intervening ventricular sense (VS) event, and a single VP is delivered ("long"). The pause (bracket) is only 830 ms, because of rate modulation. An early-coupled VPD (390 ms) ("short") anticipates VF onset. Abbreviations as in Figure 1.