KCNH2 and catecholaminergic polymorphic ventricular tachycardia: Pathogenic variants in CACNA1C and RYR1 (malignant hyperthermia), KCNH2 and SCN5A (long QT syndrome), RYR2 (catecholaminergic polymorphic ventricular tachycardia), and LDLR (hyperlipidemia)