From the Guidelines
The coved shape in Brugada syndrome is characterized by a downsloping ST-segment elevation of at least 2 mm (0.2 mV) followed by a negative T-wave, creating a "coved" or dome-like shape in the right precordial leads (V1-V2) on an electrocardiogram (ECG). This distinctive ECG finding is essential for diagnosing Brugada syndrome, a genetic heart disorder that increases the risk of sudden cardiac death due to ventricular arrhythmias, as noted in the 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death 1. The coved shape results from abnormal sodium channel function in the heart, typically caused by mutations in the SCN5A gene, which alters the electrical activity particularly in the right ventricular outflow tract.
Some key points to consider in the diagnosis of Brugada syndrome include:
- The use of high electrocardiographic electrode positioning in the second and third interspaces for electrocardiographic recording improves detection of a type 1 Brugada ECG 1.
- The type 1 Brugada ECG with coved ST elevation in right precordial leads may be present spontaneously, during fever or vagotonic states, or after medication challenge with sodium channel blockers 1.
- Patients with spontaneous coved type ST elevation and a history of syncope or prior SCA are at the highest risk for potentially lethal VA, and ICD implantation has been shown to reduce mortality in symptomatic patients with Brugada syndrome 1.
Recognition of this coved pattern is crucial for proper diagnosis and management of patients with Brugada syndrome, as it can help identify those at high risk of sudden cardiac death and guide treatment decisions, such as the use of ICDs or sodium channel blockers 1.
From the Research
Brugada Syndrome and Coved Shape
- The coved shape in Brugada syndrome is characterized by a coved-type ST-segment elevation of at least 2 mm followed by a negative T wave in either one of the right precordial leads 2, 3.
- This ECG pattern is often intermittent and may be provoked by fever or sodium channel blocker challenge 2.
- The coved shape is one of the diagnostic criteria for Brugada syndrome, which is an inherited channelopathy that alters the main transmembrane ion currents that constitute the cardiac action potential 3.
- The ECG pattern of Brugada syndrome can be classified into three types: type 1 (coved type), type 2 (saddleback type), and type 3 4, 5.
- Type 1 is characterized by a coved ST-segment elevation of at least 2 mm, while type 2 and type 3 have a saddleback or coved morphology with an ST-segment elevation of less than 2 mm 4, 5.
ECG Patterns and Diagnosis
- The diagnosis of Brugada syndrome is based on the presence of a characteristic ECG pattern, which can be dynamic and sometimes concealed 5.
- The ECG pattern can be induced by various physiologic stressors, and the absence of these patterns on isolated electrocardiograms does not exclude the diagnosis 4.
- Serial ECGs are important in diagnosis, as sudden cardiac death is often the first or only presentation of Brugada syndrome 4.
- The concept of Brugada phenocopies refers to ECG patterns characteristic of Brugada pattern that may appear and disappear in relation with multiple causes but are not related with Brugada syndrome 5.