Non-invasive cardiac activation mapping and identification of severity of epicardial substrate in Brugada Syndrome: a case report

Introduction

It has recently been shown that electrocardiographic imaging (ECGi) can be employed in individuals undergoing an ajmaline test who have Brugada Syndrome (BrS), to evaluate the extent of substrate-involved arrhythmia in the right ventricular overflow tract (RVOT). For the first time, we stratify the risk of sudden cardiac death (SCD) in BrS during ajmaline testing using the dST-Tiso interval (a robust predictor of the inducibility of ventricular arrhythmias (VAs) in the presence of drug-induced BrS type-1 pattern) in combination with ECGi technology.

Case presentation

We studied a 48-year-old man with BrS ECG type-2 pattern and presence of J-wave without a family history of SCD but with a previous syncope. Transthoracic echocardiography and cardiac magnetic resonance imaging were performed, showing normal results. The ECG was performed to assess the novel ECG marker "dST-Tiso interval." The 3D epicardial mapping of the RVOT surface was performed with the support of a non-contact cardiac mapping system in sinus rhythm during ajmaline infusion. The examination of the propagation map unveiled the presence of multiple conduction blocks in this pathologic epicardial region, and the conduction blocks were identified within the central part and/or near the boundary separating the normal and slow conduction areas.

Conclusion

The dST-Tiso interval, which lies between the onset and termination of the coved ST-segment elevation and serves as a robust predictor of VA inducibility in cases of drug-induced BrS type-1 pattern, was utilized in conjunction with ECGi technology (employed for the non-invasive confirmation and identification of the pathological substrate area). This combined approach was applied to stratify the risk of SCD in BrS during ajmaline testing, alongside clinical scores.

dST-Tiso Interval, a Novel Electrocardiographic Marker of Ventricular Arrhythmia Inducibility in Individuals With Ajmaline-Induced Brugada Type I Pattern

The aim of this study was to investigate the reliability of a novel electrocardiographic (ECG) marker in predicting ventricular arrhythmia (VA) inducibility in individuals with drug-induced Brugada syndrome (BrS) type I pattern. Consecutive patients with drug-induced type I BrS pattern underwent programmed ventricular stimulation (PVS) and, according to their response, were divided into 2 groups. Clinical characteristics and 12-lead ECG intervals before and after ajmaline infusion were compared between the 2 groups. A novel ECG marker named dST-Tiso interval consisting in the interval between the onset of the coved ST-segment elevation and its termination at the isoelectric line was also evaluated. Our cohort included 76 individuals (median age 44 years, 75% male). Twenty-five (32.9%) had VA inducibility requiring defibrillation. As compared with not inducible subjects, those with VA inducibility were more frequently male (92% vs 65%, p = 0.013), had longer PQ interval (basal: 172 vs 152 ms, p = 0.033; after ajmaline: 216 vs 200 ms, p = 0.040), higher J peak (0.6 vs 0.5 mV, p = 0.006) and longer dST-Tiso (360 vs 240 ms, p < 0.001). The dST-Tiso showed a C-statistics of 0.90 (95% confidence interval: 0.82 to 0.99) and an adjusted odds ratio for VA of 1.03 (1.01 to 1.04, p < 0.001). A dST-Tiso interval >300 ms yielded a sensitivity of 92.0%, a specificity of 90.2%, positive and negative predictive values of 82.1% and 95.8%. In conclusion, the dST-Tiso interval is a powerful predictor of VA inducibility in drug-induced BrS type I pattern. External validation is needed, but this marker might be useful in the clinical counseling process of these individuals before invasive PVS.

Remote monitoring of cardiac implantable devices during COVID-19 outbreak: "keep people safe" and "focus only on health care needs"

BACKGROUND

The COVID-19 pandemic has challenged the ability of health care organisations to provide adequate care. We report the experience of a national tertiary electrophysiology centre in the management of patients with cardiac implantable electronic devices (CIEDs) through the use of a fully remote follow-up model.

METHODS

We daily and prospectively collected remote monitoring (RM) relevant findings and following clinical actions performed from March 10^th to April 3^rd 2020, a period of suspension of routine ambulatory activity due to the national lockdown.

RESULTS

During the study period (25 days), we received 2,215 transmissions from 2,955 devices. Among them, 129 patients reported potential clinically actionable RM observations (event rate: 12.0/1000 patient-week). In 77 patients (60%), RM events triggered a clinical action, but only 5 patients needed an urgent in-hospital access (4 urgent procedures and 1 device reprogramming).

CONCLUSIONS

In the unprecedented COVID-19 pandemic, RM became an essential tool in healthcare delivery for CIED patients. We observed that RM was effective in "keep people safe" and "focus only on individuals with health care needs".

P947dST-Tiso index, a new shallow ECG marker in response to ajmaline for predicting ventricular fibrillation induction in Brugada patients

Introduction - No study has been performed to investigate the role of drug-induced ECG morphology modifications as potential risk factors for the development of malignant arrhythmias in patients with Brugada syndrome.

Purpose - The aim of this study is to introduce a new index to improve asymptomatic patient stratification  and to report the first case of a patient with Brugada syndrome undergoing ajmaline testing that has been evaluated using a diagnostic 252-lead ECG vest.

Methods - From December 2018 to April 2019, 26 consecutive patients [mean age 39.9 (30–59) years, 18 male] with no cardiovascular risk factors underwent ajmaline testing. By evaluating ECG recordings after ajmaline administration, we calculated an index that we called "dST-Tiso", that is the duration of the positive component of the ST-T wave to the isoelectric line, in V1 and/or V2.

Results- Out of 26 patients, 16 (61.5%) had a positive test, with type 1 (coved-type) ECG diagnostic pattern in leads V1-V2 from the 2nd, 3rd and 4th intercostal spaces.  The mean recorded dST-Tiso value was 239 ± 76 ms. The ECG showed T-wave above the isoelectric line in 5 patients with a significantly higher dST-Tiso value (on average 360 ± 56 ms), and biphasic T-waves below the isoelectric line in 11 patients with a dST-Tiso value of 209 ± 42 ms (Mann-Whitney, p = 0.039). All patients with positive ajmaline test underwent programmed electrical stimulation (PES). Ventricular fibrillation was induced during PES in all 5 patients with stretched dST-Tiso. In the remaining 11 patients without stretched dST-Tiso, no ventricular arrhythmia was induced by PES.  Fig 1 Moreover, using non-invasive high-density electrocardiographic mapping (252-lead ECG vest), 3 patients with dST-Tiso positive pattern received a second ajmaline protocol, with assessment of both the depolarization and repolarization phases.

Conclusion - The ECG pattern of prolonged dST-Tiso seems to have a significant impact on safety during PES and may have potential for stratifying risk of sudden death in patients with PES-induced ventricular tachycardia/fibrillation.

Abstract Figure 1. Patients’ flowchart.