The role of remote rhythm monitoring during non-acute periods in patients with TANGO2-related metabolic encephalopathy and arrhythmias

Abstract

BACKGROUND. TANGO2-related metabolic encephalopathy and malignant arrhythmias is a newly acknowledged autosomal recessive genetic disease caused by pathogenic variants in the TANGO2 gene. Clinical characteristics include recurrent acute metabolic crises related to rhabdomyolysis, prolongation of QT interval in the electrocardiogram and less frequently, a characteristic electrocardiographic pattern of Brugada Syndrome. These alterations lead to torsade de pointes (most common arrhythmia seen in this disorder) followed by ventricular tachycardia, ventricular fibrillation, and even in some cases, sudden cardiac death. Arrhythmias are the most usual cause of death in this patients and ventricular dysfunction is also described. Due to the extreme rarity of the disease, there are no standardized treatment protocols or guidelines. It is known that patients during non-acute periods tend to be without any cardiac arrythmia, but here is when it comes the importance of the rhythm monitoring by the remote cardiac monitor system with an implantable loop recorder. With this tool, apart from the education of familiars about the syndrome and genetic counselling, we try to detect earlier the arrythmias to treat our patients as soon as possible and thus prevent episodes of malignant arrhythmias and even sudden cardiac death. HYPOTHESY AND OBJECTIVES. In this cross-sectional study, we suggested that patients with TANGO2-related metabolic encephalopathy and arrhythmias diagnosed and/or managed in Hospital Sant Joan de Déu present a normal electrocardiogram during non-acute periods, measured by the remote cardiac monitor system. METHODS AND MATERIALS. It was designed a cross-sectional study with a total sample of 11 anonymized patients with TANGO2 - related metabolic encephalopathy and arrhythmias. The objective was to analyse demographical data,

clinical characteristics, genetic background, and describe the electrocardiographic characteristics data during non- acute periods recorded by implantable loop recorder from June 2019 to now.

RESULTS AND DISCUSSION. In this first-year follow-up post-implantation of implantable loop recorder we found a total of seven rhythm alterations during non-acute periods presented in three of the patients with implanted monitor. All these patients come up with bradycardias, two with sinoatrial block, one with auriculoventricular block of 1st grade and another one with paroxysmal supraventricular tachycardia. Consequently, it was implanted a heart pacemaker device in a patient with auriculoventricular block 1st grade symptomatic and bradycardia episodes, whether in the other two only periodical controls were requested as there are minor rhythm alterations. CONCLUSIONS. Our results conclude that not all patients with TANGO2-related metabolic encephalopathy and arrhythmia during non-acute periods included in our study, specifically three of them, do not present any rhythm alteration regardless of its severity and consequences. Other conclusions reached are that long QT isthe most frequent arrhythmia through metabolic crises and ventricular arrhythmias are the most fatal ones