Table 3 A literature review of neonatal hereditary long Q-T syndromes cases and their management process

Lowin et al. 2022 [26]

47-year-old Female

Presented with electrical storm and received overall six ICD shocks when arrived at ED

HX: Diagnosed with Congenital LQTS Type 2 at the age of 23 after surviving SCD, asymptomatic during the past 24 years

PH/E: HR: 90 BP:105/66

Lab: Positive Hs-cTnI, Increased CK MB

ECG: Ventricular pacing triggered by atria and distinct ST segment elevations in the inferior leads

CAG: subtotal occlusion of the RCA

Dx: AMI on LQTS

Tx: Drug-eluting stent implantation. Resuming AV conduction immediately after PCI and the following non-paced ECG revealed a prolonged QT interval with elevated cardiac enzymes. The patient was put on BB, DAPT, and statins and discharged in good condition

Prog: discharged in good condition

Matsushita et al. 2022 [27]

Two daughters

1-year-old Female

New-born female

Asymptomatic until the initial pediatric check, her ECG recording showed a normal QTc interval of 419 ms, notched T waves, frequently and specifically detected as LQTS in the precordial leads, V-3 to V-5

The second daughter had no arrhythmia and presented a normal QTc interval of 429 ms without notched T waves or other abnormalities

LAB: In PSGT, the siblings were carriers of the nonsense gene variant Q391X

Dx: Long QT syndrome due to nonsense (Q391X variant)

Tx: Regular follow-ups, including PH/EX and planning for Holter ECG or ECG,

As part of the follow-up, parents and family doctors were alarmed that the children might easily develop arrhythmia due to dehydration, hypokalemia, or treatment with particular medications. The necessity of performing an ECG during syncope, palpitation, or seizure. Close supervision by caregivers while swimming or performing vigorous exercise. The placement of an automated external defibrillator in the nursery and at their house

Aziz et al. 2014 [28]

29-year-old-Male (Caucasian)

Presented with two weeks of altered mental status with combative behavior, worsening dyspnea, and syncopal episodes

ECG: long cQT interval of 710 ms and presence of U waves correlating

LAB: K;3.1, 3 episodes of VT, resolved spontaneously after lasting for 5–7 s

Dx: CCU Admit, Epinephrine infusion at a rate for 10 min cQT 570 ms, then increased dose for another 5 min, at the end of which QTc prolonged to 600 ms

The patient was given an External defibrillator vest and discharged home with close outpatient follow-up and a plan for repetition of the QTc stress test in 2 months for evaluation of the need for AICD

Saarel et al. 2015 [29]

2 year-old-male

(African American)

A biracial full-term female newborn presented on the day of life with 2:1 AV block and cardiac arrest due to an extremely long QT interval (> 600 ms) and TdP

Genetic Test: Single sodium channel defect, SCN5A Leu 618 Phe: LQT3

Several repeating VF episodes and syncope, Mexiletine, BB, ICD placement, and several awakening shocks by ICD, which caused PTSD

A single chamber epicardial VVI pacemaker was placed through a limited sternotomy, and propranolol Resolved the AV block by the age of three months; 2:1 had resolved, required removal of the chronic system and placement of a new single-chamber pacemaker system via left thoracotomy

At 12: Severe VF and TdP, controlled by Mexiletine, Nadolol, shock,

Plan: spironolactone and ranolazine for HF

Tamayo-Trujillo et al. 2024 [30]

14-year-old Ecuadorian female

Referred to the arrhythmia unit due to 2-months of syncope,

FH: Positive,

ECG: sinus rhythm, abnormal T waves, and a prolonged QTc interval (528 ms)

Aberrancy and LQTS detected after the stress test, TTE: NL High Schwartz Score; 5

Genetic test: A pathogenic variant in the gene p.(Ala614Val) was detected, and an abnormal ECG

Continuing the symptoms despite taking Propranolol

Genetic Test + ECG: LQT2 syndrome. The high SCD risk: ICD implantation→ no response (persistent VT and prolonged QTc)→ lifestyle changes, adequate serum K + levels check, exercise restriction, and a reduced auditory trigger→ improvement but no resolution of symptoms