A Practical Approach to the Investigation of an rSr’ Pattern in Leads V1-V2

In Situ Formation of Conductive Epidermal Electrodes Using a Fully Integrated Flexible System and Injectable Photocurable Ink

In situ fabrication of wearable devices through coating approaches is a promising solution for the fast deployment of wearable devices and more adaptable devices for different sensing demands. However, heat, solvent, and mechanical sensitivity of biological tissues, along with personal compliance, pose strict requirements for coating materials and methods. To address this, a biocompatible and biodegradable light-curable conductive ink and an all-in-one flexible system that conducts in situ injection and photonic curing of the ink as well as monitoring of biophysiological information have been developed. The ink can be solidified through spontaneous phase changes and photonic cured to achieve a high mechanical strength of 7.48 MPa and an excellent electrical conductivity of 3.57 × 10⁵ S/m. The flexible system contains elastic injection chambers embedded with specially designed optical waveguides to uniformly dissipate visible LED light throughout the chambers and rapidly cure the ink in 5 min. The resulting conductive electrodes offer intimate skin contact even with the existence of hair and work stably even under an acceleration of 8 g, leading to a robust wearable system capable of working under intense motion, heavy sweating, and varied surface morphology. Similar concepts may lead to various rapidly deployable wearable systems that offer excellent adaptability to different monitoring demands for the health tracking of large populations.

The "rSr' ECG pattern" is not always a Brugada ECG pattern

The differential diagnosis of an rSr' pattern in leads V1-V2 on the surface ECG is a common issue in daily practice. This article is protected by copyright. All rights reserved.

Andersen-Tawil Syndrome: A Comprehensive Review

Andersen-Tawil syndrome (ATS) is a very rare orphan genetic multisystem channelopathy without structural heart disease (with rare exceptions). ATS type 1 is inherited in an autosomal dominant fashion and is caused by mutations in the KCNJ2 gene, which encodes the α subunit of the K+ channel protein Kir2.1 (in ≈ 50-60% of cases). ATS type 2 is in turn linked to a rare mutation in the KCNJ5-GIRK4 gene that encodes the G protein-sensitive-activated inwardly rectifying K+ channel Kir3.4 (15%), which carries the acetylcholine-induced potassium current. About 30% of cases are de novo/sporadic, suggesting that additional as-yet unidentified genes also cause the disorder. A triad of periodic muscle paralysis, repolarization changes in the electrocardiogram, and structural body changes characterize ATS. The typical muscular change is episodic flaccid muscle weakness. Prolongation of the QU/QUc intervals and normal or minimally prolonged QT/QTc intervals with a tendency to ventricular arrhythmias are typical repolarization changes. Bidirectional ventricular tachycardia is the hallmark ventricular arrhythmia, but also premature ventricular contractions, and rarely, polymorphic ventricular tachycardia of torsade de pointes type may be present. Patients with ATS have characteristic physical developmental dysmorphisms that affect the face, skull, limbs, thorax, and stature. Mild learning difficulties and a distinct neurocognitive phenotype (deficits in executive function and abstract reasoning) have been described. About 60% of affected individuals have all features of the major triad. The purpose of this review is to present historical aspects, nomenclature (observations/criticisms), epidemiology, genetics, electrocardiography, arrhythmias, electrophysiological mechanisms, diagnostic criteria/clues of periodic paralysis, prognosis, and management of ATS.

Diagnosis of type 2 Brugada pattern: insights from a pilot survey

BACKGROUND

Differentiation of Type 2 Brugada Pattern (BP) from incomplete right bundle branch block or normal rSr' pattern can be insidious. The aim of this study was to assess interobserver and intraobserver agreement in the diagnosis of type 2 BP in a cohort of cardiologists with different skills.

METHODS

We collected 14 ECGs with a positive terminal deflection of the QRS complex in lead V1 and V2 at the 4^th intercostal space. We proposed these ECGs, specifying to use 2012 Consensus conference criteria for diagnosis of type 2 BP, to 42 participants: 14 arrhythmologists, 14 general cardiologists and 14 electrophysiology (EP) fellows. The same 14 ECGs, with a different order, were proposed fifteen days later to the same cohort to assess intraobserver variability. Authors analyzed all 14 ECGs in order to assess whether 2012 Consensus Conference criteria for BP were fulfilled. All patients underwent provocative test with IC antiarrhythmics drugs (flecainide) in order to exclude or confirm the diagnosis of Brugada Syndrome (BrS).

RESULTS

Slight interobserver agreement (Fleiss K<0.20) in the diagnosis of type 2 BP was observed in all three categories of cardiologists. Considering five operators per class, intraobserver agreement is variable (k ranging from 0.000 to 0.857), with a slight superiority of arrhytmologists (k minimum value 0.276; k maximum value 0.857).

CONCLUSIONS

This study demonstrated, for the first time, a low interobserver agreement in diagnosis of type 2 BP in categories of cardiologists with different abilities. Reproducibility of type 2 BP diagnosis (intraobserver agreement) is poor, even among experts. These findings highlight the difficulties in analysis of ECG with BrS suspicion and, therefore, underscore the key role of clinical and anamnestic data.

Methods for Improving the Diagnosis of a Brugada ECG Pattern

Brugada syndrome (BrS) is an inherited channelopathy that predisposes individuals to malignant arrhythmias and can lead to sudden cardiac death. The condition is characterized by two electrocardiography (ECG) patterns: the type-1 or "coved" ECG and the type-2 or "saddleback" ECG. Although the type-1 Brugada ECG pattern is diagnostic for the condition, the type-2 Brugada ECG pattern requires differential diagnosis from conditions that produce a similar morphology. In this article, we present a case that is suspicious but not diagnostic for BrS and discuss the application of ECG methodologies for increasing or decreasing suspicion for a diagnosis of BrS.