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Figure 2 DDD/R

For pacing facilitated S-L-S, the pacing rate approximates the lower programmed rate (1,000 ms). Intermittent far-field R-wave oversensing (AR) occurs after VPs. An atrial premature beat 250 ms after far-field R-wave (asterisk) is tracked, and a synchronized VP occurs at the upper limit of 500 ms ("short"). A 1,060-ms pause (bracket) ("long") follows, due to normal lower rate behavior. A VPD (610 ms) ("short") after the final VP anticipates VF onset. Abbreviations as in Figure 1.