The Beneficial Role of Telemedicine for Arrhythmic Risk Stratification in Asymptomatic Brugada Syndrome: An Exemplary Case Report

Telemedicine and remote monitoring devices, including implantable loop recorders (ILR), are increasingly adopted in the cardiologic setting. These are valuable tools in the arrhythmic stratification of patients at risk of sudden cardiac death, providing a tailored therapeutic management to prevent lethal arrhythmias. We report a case of an asymptomatic 18-year-old boy with a family history of syncope and cardiac arrest, who had a diagnosis of Brugada syndrome with an inducible type 1 pattern and carrier of a missense mutation of the SCN5A gene. In light of the risk factors, although not recommended by current guidelines, we decided to proceed with the implantation of an ILR with remote monitoring service. A few months later, an episode of asymptomatic sustained polymorphic ventricular tachycardia was promptly observed by the remote monitoring, leading to a timely implantation of a subcutaneous cardiac implantable defibrillator.

Role of Provocable Brugada ECG Pattern in The Correct Risk Stratification for Major Arrhythmic Events

The so-called Brugada syndrome (BS), first called precordial early repolarization syndrome (PERS), is characterized by the association of a fascinating electrocardiographic pattern, namely an aspect resembling right bundle branch block with a coved and sometime upsloping ST segment elevation in the precordial leads, and major ventricular arrhythmic events that could rarely lead to sudden death. Its electrogenesis has been related to a conduction delay mostly, but not only, located on the right ventricular outflow tract (RVOT), probably due to a progressive fibrosis of the conduction system. Many tests have been proposed to identify people at risk of sudden death and, among all, ajmaline challenge, thanks to its ability to enhance latent conduction defects, became so popular, even if its role is still controversial as it is neither specific nor sensitive enough to guide further invasive investigations and managements. Interestingly, a type 1 pattern has also been induced in many other cardiac diseases or systemic diseases with a cardiac involvement, such as long QT syndrome (LQTS), arrhythmogenic right ventricular cardiomyopathy (ARVC), hypertrophic cardiomyopathy (HCM) and myotonic dystrophy, without any clear arrhythmic risk profile. Evidence-based studies clearly showed that a positive ajmaline test does not provide any additional information on the risk stratification for major ventricular arrhythmic events on asymptomatic individuals with a non-diagnostic Brugada ECG pattern.

Brugada Phenocopy Induced by Recreational Drug Use

Recreational drugs are commonly abused in all age groups. Intoxication with these substances can induce silent but significant electrocardiographic signs which may lead to sudden death. In this case study, we present a 49-year-old male with no medical comorbidities who came to the emergency department requesting opioid detoxification. Toxicology screen was positive for cocaine, heroin, and cannabis. Initial electrocardiogram (EKG) showed features of a Brugada pattern in the right precordial leads, which resolved within one day into admission. This presentation is consistent with the recently recognized clinical entity known as Brugada phenocopy.

Prognosis after implantation of cardioverter-defibrillators in Korean patients with Brugada syndrome

PURPOSE

Our study aims to analyze prognosis after implantable cardioverter-defibrillator (ICD) implantation in Korean patients with Brugada syndrome (BrS).

MATERIALS AND METHODS

This was a retrospective study of BrS patients implanted with an ICD at one of four centers in Korea between January 1998 and April 2012. Sixty-nine patients (68 males, 1 female) were implanted with an ICD based on aborted cardiac arrest (n=38, 55%), history of syncope (n=17, 25%), or induced ventricular tachyarrhythmia on electrophysiologic study in asymptomatic patients (n=14, 20%). A family history of sudden cardiac death and a spontaneous type 1 electrocardiography (ECG) were noted in 13 patients (19%) and 44 patients (64%), respectively.

RESULTS

During a mean follow-up of 59±46 months, 4.6±5.5 appropriate shocks were delivered in 19 patients (28%). Fourteen patients (20%) experienced 5.2±8.0 inappropriate shocks caused by supraventricular arrhythmia, lead failure, or abnormal sensing. Six patients were admitted for cardiac causes during follow-up, but no cardiac deaths occurred. An episode of aborted cardiac arrest was a significant predictor of appropriate shock, and the composite of cardiac events in the Cox proportional hazard model [hazard ratio (95% confidence interval) was 11.34 (1.31-97.94) and 4.78 (1.41-16.22), respectively]. However, a spontaneous type 1 ECG was not a predictor of cardiac events.

CONCLUSION

Appropriate shock (28%) and inappropriate shock (20%) were noted during a mean follow-up of 59±46 months in Korean BrS patients implanted with an ICD. An episode of aborted cardiac arrest was the most powerful predictor of cardiac events.

Is this a philosophic issue? Do patients with drug-induced Brugada type ECG have poor prognosis? (Pro)

Brugada syndrome (BS) has an intermittent or concealed type, which can be unmasked by the sodium (Na(+))-channel-blocker challenge test. The appropriate risk stratification of patients with a drug-induced Brugada-type electrocardiographic (ECG), especially those without a history of syncope or aborted sudden cardiac death, remains unclear. The prognosis of patients with BS depends on the clinical type, cardiac arrest, syncope or if asymptomatic. The ratio of the asymptomatic group varies from 56.9% to 63.6% and, furthermore, their annual cardiac event rate is relatively lower at 0.24-3.6% compared with the cardiac arrest group. Patients with a drug-induced Brugada-type ECG have a poor prognosis if they had a history of ventricular fibrillation (VF) or aborted sudden cardiac death, because their risk becomes similar to that of patients with spontaneous Brugada-type ECG. They have the disturbance of the Na(+)-channel and the electrophysiologic substrate of VF, proven by the high inducibility of VF by stimulation test even in patients without spontaneous VF. Spontaneous VF will never occur if there is no VF substrate. Implantable cardioverter-defibrillators will certainly protect them, so patients with a drug-induced Brugada-type ECG, even without a history of VF or aborted sudden cardiac death, should be considered to have a poor prognosis.