Congenital Long QT Syndromes (LQTS) are a heterogeneous group of channelopathies that cause an alteration in the repolarization phase, leading to a prolonged QT interval on the electrocardiogram. This condition provides the substrate for the development of malignant cardiac arrhythmias, such as bradycardia, atrioventricular block and polymorphic ventricular tachycardia with torsades de pointes. Starting from the analysis of a case involving a newborn with hemodynamically stable bradycardia on the first day of life, a literature review was conducted on the management of type 1 Long QT Syndrome, with a focus on cases involving carriers of the proband’s pathogenic variant, to identify best clinical practice actions for the diagnosis and treatment of neonatal-onset, particularly on those cases caused by the rare pathogenic variant c.1017_1019delCTT (p.Phe340del) in exon 7 of the KCNQ1 gene. Neonatal bradycardia is a nonspecific clinical sign that may be the first manifestation of Long QT Syndrome, a pathological substrate with a high risk of SIDS in the first year of life. The persistence of a prolonged QT interval (≥470 ms) after 3-4 weeks of life indicates the need to start beta-blocker therapy, even before confirmation by genetic testing. The patient’s c.1017_1019delCTT (p.Phe340del) variant, located in exon 7 of the KCNQ1 gene, which codes for the second half of the pore of the voltage-gated Kv7.1 channel, results in a haploinsufficiency effect on the membrane protein and confirms the diagnosis of familial type 1 Long QT Syndrome. Given that no arrhythmic events occurred during the lives of family members carrying the same proband mutation, even before beta-blocker therapy was initiated, one might speculate on the benign nature of the detected mutation. However, given the involvement of the transmembrane portion of the Kv7.1 voltage-gated channel, the authors strongly recommend maintaining therapy and continuing periodic cardiological follow-up.