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. 2019 Oct 16;8(21):e013750. doi: 10.1161/JAHA.119.013750

Figure 7.

Figure 7

Example of the use of R‐wave triggered pacing during the absolute refractory period to suppress spontaneous repolarization alternans (RA) during acute ischemia. Alternans voltage (A) and Kscore (B) are plotted for intracardiac leads CS2CS7, CS2LV7, and CS2LV10. R‐wave triggered pacing (amplitude: +4 mA, pulse width: 10 ms, R‐wave coupling: 10 ms) is delivered from the right ventricular apex (RV12). a, spontaneous visible RA at baseline; (b) pacing delivered on every even beat results in RA suppression; (c) termination of pacing results in rising of the alternans voltage and Kscore to the baseline level. Transitions between interventions are indicated by dashed vertical lines, while red horizontal lines indicate the mean values of the alternans voltage and Kscore during each intervention. C, ECG morphology changes during the above‐described interventions. a, visible RA at baseline, (b) pacing decreases the RA level, (c) pacing is interrupted and RA becomes again visible. Panels show the median odd (red)/even (blue) beats of a 128‐beat sequence during each intervention.