Although LQT8 is caused by GOF mutations in Cav1.2 LTCCs, case reports of patients treated with the LTCC blockers verapamil or diltiazem for prevention of ventricular fibrillation episodes (Jacobs et al., 2006; Shah et al., 2012; Liu et al., 2016) showed mixed effects. Here, CACNA1C is linked to long QT syndrome 8.