Related Experiment Video
Updated: May 30, 2025

Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation
Published on: January 16, 2019
Long QT Syndrome: LQT3 Variant Presenting in a Bradycardic Newborn
Catarina Afonso1, Débora A Mendes2, Rita V Queirós3
1Family Medicine, USF (Unidade de Saúde Familiar) Afonsoeiro, Unidade Local de Saúde do Arco Ribeirinho, Montijo, PRT.
Abstract:
Long QT Syndrome (LQTS) is a rare hereditary canalopathy, characterized by prolonged ventricular repolarization, which can lead to malignant tachyarrhythmias at a young age. Treatment typically involves healthy lifestyle changes and β-blocker therapy. In specific cases, the implantation of an implantable cardioverter defibrillator (ICD) can be an option. In this report, we present the case of a newborn presenting with bradycardia in his initial screening examination, who was subsequently diagnosed with LQTS, specifically variant LQT3, a rare finding.
Related Concept Videos
Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers
Disturbances in Heart Rhythm
Arrhythmias are categorized by their speed, rhythm, and origin. A slow...
ECG Interpretation of Arrhythmias I: Sinus Arrhythmias
Types of Arrhythmias
Sinus Node Arrhythmias
Sinus Bradycardia: Originating from the sinoatrial (SA) node, sinus bradycardia involves slower impulses, resulting in a heart rate of less than 60 beats per minute (bpm). Causes include sleep, vagal stimulation, beta-blockers, hypothyroidism,...
Cardiac Action Potential
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials
Decreased pulse rate
There are specific risk factors that can elevate the likelihood of developing bradycardia. Advanced age is a significant factor, with...
Antiarrhythmic Drugs: Class I Agents as Sodium Channel Blockers
Class 1A Antiarrhythmic Drugs: These drugs work by moderately blocking sodium channels,...

