Electrocardiographic pattern of Brugada syndrome disclosed by a febrile illness: clinical and therapeutic implications.
ABSTRACT Recent studies have identified a direct link between the ionic mechanisms responsible for the electrocardiographic (ECG) pattern of the Brugada syndrome (BS) and the in vitro experimental temperature, pointing to the possibility that some BS patients may display the ECG phenotype only during a febrile state, being in this setting at risk of lethal arrhythmias.
A 53-year-old man referred to the emergency room for abdominal pain and fever. The ECG showed dome-shaped ST-segment elevation in V1-V3, as in the typical BS. The personal and family history were unremarkable for syncope and sudden death and physical, laboratory and ultrasound examinations were negative. On day 3, at normal body temperature, the patient's ECG returned to normal and the ECG abnormalities were later reproduced with intravenous flecainide. The patient refused the implantation of a loop recorder and was discharged after 6 days. He has remained asymptomatic during 2 years of follow-up.
The typical ECG phenotype of BS disclosed by a febrile illness confirms the in vitro experimental data that previously established a correlation between ECG pattern of BS and temperature variations. The clinical and therapeutic implications of these findings are discussed.
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ABSTRACT: Mutations in the α-subunit of cardiac sodium channel gene SCN5A can lead to the overlapping phenotypes of both the Brugada and type 3 long QT syndromes. However, the combination of Brugada and a short QT phenotype resulting from mutation in SCN5A has not previously been described. A man with concomitant Brugada-like and short QT electrocardiogram (ECG) was identified and the SCN5A gene was sequenced. Whole-cell patch clamp analysis of human embryo kidney (HEK) 293 cells expressing a SCN5A channel with the patient's sequence was used to investigate the biophysical properties of the channel. The patient with the family history of sudden death showed Brugada-like and short QT interval ECG. Sequence anlaysis of the coding region of the SCN5A gene, identified a G to A heterozygous missense mutation at nucleotide site 2066 that resulted in a amino-acid substitution of arginine to histidine at amino-acid site 689 (R689H). Patch clamp analysis showed that the R689H failed to generate current when heterologously expressed in HEK293 cells, indicating it was a loss-of-function mutation. Our finding firstly showes that a heterozygous missense mutation R689H in SCN5A gene results in the loss of protein function and the coexistents of the Brugada-like and short QT interval ECG phenotypes.European journal of human genetics: EJHG 04/2012; 20(11):1189-92. · 3.56 Impact Factor
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ABSTRACT: The risk for lethal ventricular arrhythmias is increased in individuals who carry mutations in genes that encode cardiac ion channels. Loss-of-function mutations in SCN5A, the gene encoding the cardiac sodium channel, are linked to Brugada syndrome (BrS). Arrhythmias in BrS are often preceded by coved-type ST-segment elevation in the right-precordial leads V1 and V2. Loss-of-function mutations in KCNH2, the gene encoding the cardiac ion channel that is responsible for the rapidly activating delayed rectifying potassium current, are linked to long-QT syndrome type 2 (LQT-2). LQT-2 is characterised by delayed cardiac repolarisation and rate-corrected QT interval (QTc) prolongation. Here, we report that the risk for ventricular arrhythmias in BrS and LQT-2 is further increased during fever. Moreover, we demonstrate that fever may aggravate coved-type ST-segment elevation in BrS, and cause QTc lengthening in LQT-2. Finally, we describe molecular mechanisms that may underlie the proarrhythmic effects of fever in BrS and LQT-2. (Neth Heart J 2010;18:165-9.).Netherlands heart journal: monthly journal of the Netherlands Society of Cardiology and the Netherlands Heart Foundation 03/2010; 18(3):165-9. · 1.41 Impact Factor
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ABSTRACT: Brugada syndrome is an inherited autosomal dominant-type disease characterized by ST-segment abnormalities and increased fatal ventricular tachyarrhythmias. We hereby present a 57-years-old patient with no symptoms or history of cardiovascular disease, diagnosed with febrile respiratory infection (39℃). Electrocardiographic (ECG) findings were typical of Brugada-like type I syndrome that gradually turned to Brugada type II and III, following fever remission, and finally became normal. Other clinical evaluation tests (echocardiographic evaluation, treadmill stress test, Holter ECG, procainamide provocation test) did not relate to Brugada syndrome.Hippokratia 07/2010; 14(3):221-3. · 0.59 Impact Factor