The small differences in Ca2+ wave frequency between CPVT1 and WT cardiomyocytes observed here do not seem to reflect the large effects of the CPVT1 mutation on arrhythmias in vivo (e.g., 50%–75% VT incidence in RyR2‐RS groups compared to 0% in WT). The gene discussed is RYR2; the disease is cardiac arrhythmia.