Congenital long QT syndrome: Should citric fruits be avoided? A case report of a cLQTS type 1 with unusual QTc prolongation with citric juices

Abstract

Congenital long QT syndromes (cLQTS) are relatively rare diseases in which QT interval is prolonged due to several mutations on ion channels involved in cardiac cell repolarization. This condition confers higher risk of malignant arrhythmias and sudden cardiac death, and it is widely accepted that substances that prolong QT interval should be avoided by these patients. Most of these substances are antibiotics and non-antibiotics drugs, but almost nothing is known about frequently consumed fruits and juices. We report the case of a patient with a previously asymptomatic cLQTS type 1 (cLQTS1) with unusual QT prolongation of 167 milliseconds (ms) related to the consumption of large amounts of citric juices (oranges and lemons). A literature review was done for better understanding of its influence on QT interval duration and to know the concentration of flavonoids on citric fruits. <Learning objective: The objective is to emphasize the relatively new concept of "proarrhythmic food". A short number of clinical trials have demonstrated a modest QT interval prolongation with grapefruit juice, but nothing has been previously described of other citric fruits. We present a case of a patient with cLQTS1 that suffered severe QT interval prolongation related to orange and lemon juice consumption. Substances on these fruits involved in QT prolongation and pathophysiological mechanism are discussed.>.

Keywords: Citric fruits; Flavonoids; Long QT syndrome; Prolonged QT interval in electrocardiography and sudden death; QT interval prolongation.