Carnitine deficiency induces a short QT syndrome

Heart Rhythm. 2016 Jan;13(1):165-74. doi: 10.1016/j.hrthm.2015.07.027. Epub 2015 Jul 17.

Abstract

Background: Short QT syndrome is associated with an increased risk of cardiac arrhythmias and unexpected sudden death. Until now, only mutations in genes encoding the cardiac potassium and calcium channels have been implicated in early T-wave repolarization.

Objective: The purpose of this study was to confirm a relationship between a short QT syndrome and carnitine deficiency.

Methods: We report 3 patients affected by primary systemic carnitine deficiency and an associated short QT syndrome. Ventricular fibrillation during early adulthood was the initial symptom in 1 case. To confirm the relationship between carnitine, short QT syndrome, and arrhythmias, we used a mouse model of carnitine deficiency induced by long-term subcutaneous perfusion of MET88.

Results: MET88-treated mice developed cardiac hypertrophy associated with a remodeling of the mitochondrial network. The continuous monitoring of electrocardiograms confirmed a shortening of the QT interval, which was negatively correlated with the plasma carnitine concentration. As in humans, such alterations coincided with the genesis of ventricular premature beats and ventricular tachycardia and fibrillation.

Conclusion: Altogether, these results suggest that long-chain fatty acid metabolism influence the morphology and the electrical function of the heart.

Keywords: Carnitine deficiency; Electrophysiological remodeling; Short QT syndrome; Sudden death; Ventricular arrhythmias.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Animals
  • Arrhythmias, Cardiac* / diagnosis
  • Arrhythmias, Cardiac* / etiology
  • Arrhythmias, Cardiac* / physiopathology
  • Arrhythmias, Cardiac* / prevention & control
  • Cardiomyopathies* / complications
  • Cardiomyopathies* / diagnosis
  • Cardiomyopathies* / drug therapy
  • Cardiomyopathies* / genetics
  • Cardiomyopathies* / physiopathology
  • Carnitine / administration & dosage
  • Carnitine / blood
  • Carnitine / deficiency*
  • Carnitine / genetics
  • Child, Preschool
  • Echocardiography, Doppler / methods
  • Electrocardiography / methods
  • Electrophysiologic Techniques, Cardiac
  • Female
  • Humans
  • Hyperammonemia* / complications
  • Hyperammonemia* / diagnosis
  • Hyperammonemia* / drug therapy
  • Hyperammonemia* / genetics
  • Hyperammonemia* / physiopathology
  • Infant
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mitochondria, Heart / metabolism
  • Mitochondria, Heart / pathology
  • Muscular Diseases* / complications
  • Muscular Diseases* / diagnosis
  • Muscular Diseases* / drug therapy
  • Muscular Diseases* / genetics
  • Muscular Diseases* / physiopathology
  • Treatment Outcome

Substances

  • Carnitine

Supplementary concepts

  • Short Qt Syndrome
  • Systemic carnitine deficiency