Figure 1: Arrhythmia induction in ex-vivo retrograde perfused hPLN^R14del (R14del) and hPLN^WT (WT) murine hearts.

a. Schematic describing the generation of the mouse models with knock-in hPLN^WT and hPLN^R14del. H2BGFP expressed under the control of endogenous mouse PLN promoter. b. Pacing protocol used on the ex-vivo perfused hearts. The median of the pacing frequency range in the second segment of the protocol (with ISO) was chosen as the cut-off frequency (i.e. at 22.5Hz). c. Representative 2-sec optical AP recordings showing the initiation of sustained VT in R14del but not WT hearts in response to an identical challenge. d. Up to a cut-off frequency of 22.5Hz, sustained VT was induced in 67% of R14del hearts vs. 25% of WT hearts, exclusively upon exposure to ISO.