Abnormally high risk of stroke in Brugada syndrome

Atrial Abnormalities in Brugada Syndrome: Evaluation With ECG Imaging

BACKGROUND

Patients with Brugada syndrome (BrS) have an increased risk of arrhythmias, including atrial tachyarrhythmias (ATas).

OBJECTIVES

The purpose of this study was to assess underlying atrial cardiomyopathy in BrS and the effect of ajmaline (AJM) test on the atrium of BrS patients using electrocardiogram imaging (ECGI).

METHODS

All consecutive patients diagnosed with BrS in a monocentric registry were screened and included if they met the following criteria: 1) BrS diagnosed following current recommendations; and 2) ECGI map performed before and after AJM with a standard protocol. Consecutive patients with no structural heart disease or BrS who had undergone ECGI were included as a control group. Genetic analysis for SCN5A was performed in all BrS patients. Total atrial conduction time (TACT) and local atrial conduction time (LACT) were calculated from atrial ECGI. The primary endpoint was ATas during follow-up.

RESULTS

Forty-three consecutive BrS patients and 40 control patients were included. Both TACT and LACT were significantly prolonged in BrS patients compared with control patients. Furthermore, TACT and LACT were significantly higher after AJM administration and in BrS patients who were carriers of a pathogenic/likely pathogenic SCN5A variant. After a mean follow-up of 40.9 months, 6 patients experienced a first ATa occurrence (all in the BrS group, 13.9%). TACT was the only independent predictor of ATas with a cutoff of >138.5 ms (sensitivity 0.92 [95% CI: 0.83-0.98], specificity 0.70 [95% CI: 0.59-0.81]).

CONCLUSIONS

ECGI-calculated TACT and LACT are significantly prolonged in BrS patients compared with control patients, and in BrS patients after AJM. This may be consistent with a concealed atrial cardiomyopathy in BrS.

An Unusual First Presentation of Stroke and Seizure in a 32-Year-Old Patient With Brugada Syndrome Type 2 Electrocardiogram Pattern

We report a case of a 32-year-old lady who was admitted to the hospital with right-sided weakness that preceded an episode of seizure. On the day of admission, she woke up early in the morning with mild right-sided weakness and numbness. She had difficulty walking and later had a seizure, which was witnessed by her son. She had no signs of infection prior to this. She had no fever, chest or abdominal pain, or urinary symptoms. In the emergency department, she complained of left-sided chest tightness and heaviness, which lasted for a few minutes with associated tachycardia, electrocardiogram (ECG) was consistent with Brugada syndrome type 2. A magnetic resonant imaging (MRI) scan of her head shows a left hemispheric infarct involving the frontoparietal cortex. She was treated for an ischaemic stroke and seizure. She made a good recovery and was discharged home on secondary stroke prevention medication with community physiotherapy. She was followed up in the cardiology, genetics, and stroke outpatient clinics. The occurrence of ECG changes consistent with Brugada syndrome, stroke, and seizure in a young patient with no other risk factors for stroke is rare.

A 59-Year-Old Woman with Familial Brugada Syndrome and the c.664C>T Variant of the Sodium Voltage-Gated Channel Alpha Subunit 5 (SCN5A) Gene, Accompanied by Congenital Absence of the Right Coronary Artery, Patent Foramen Ovale, and Ischemic Stroke

Patient: Female, 59-year-old

Final Diagnosis: Absence of right coronary artery • patent foramen ovale • positive for Brugada-related gene variant

Symptoms: Angina

Medication:—

Clinical Procedure: —

Specialty: Cardiology

Atrial Fibrillation in Inherited Channelopathies

Atrial fibrillation (AF), the common sustained arrhythmia in clinical practice, has major public health implications due to its associated morbidity and increased mortality. The AF epidemic is due to the burgeoning elderly population and the identification of novel risk factors, for example, genetics. Since the diagnosis of AF has a major impact on the clinical assessment and management of patients with inherited arrhythmia syndromes, improved understanding of the cause and pathogenesis of AF has provided important insights into the underlying pathophysiological mechanisms of this common arrhythmia and identified potential mechanism-based therapies.

Incidence and predictors of atrial fibrillation in a Chinese cohort of Brugada syndrome

BACKGROUND

Atrial electrophysiological abnormalities have previously been reported in Brugada syndrome. We investigated the incidence and electrocardiographic predictors of atrial fibrillation (AF) in a Chinese cohort of Brugada syndrome patients.

METHODS

A retrospective study of Brugada syndrome patients admitted to tertiary centers in Hong Kong.

RESULTS

A total of 275 patients were included (median age at presentation: 53 [40-64], 247 (90%) males) with a median follow-up duration of 67 (31-113) months. A total of 14 patients (5%) developed AF. Inter-atrial block and AV block were found in 36% (n = 100) and 13% (n = 37) of all patients. Compared to those in sinus rhythm, patients with AF showed significantly longer P-wave duration (PWD) (125 [116-137] vs. 114 [106-124] ms, P = 0.009) and PR interval (190 [163-214] vs. 169 [153-184] ms; P = 0.023). They were more likely to develop syncope (79 vs. 43%; P = 0.012) or VT/VF (43 vs. 14%; P = 0.012), undergo electrophysiological studies (36 vs. 19%; P = 0.005) and receive ICDs (71 vs. 25%; P = 0.001). Univariate logistic regression showed that mean PWD (odds ratio [OR]: 1.03 [1.00-1.06], P = 0.021), PR interval (OR: 1.02 [1.01-1.04]; P = 0.010) and QT interval (OR: 1.02 [1.00-1.04], P = 0.012), syncope (OR: 4.80 [1.31-17.61], P = 0.018) and R-wave amplitude in lead V5 (OR: 0.30 [0.09-1.00]; P = 0.05) significantly predicted incident AF. Receiver operating characteristic analysis revealed an optimum cut-off point of 123 ms and area under the curve of 0.71 for PWD.

CONCLUSION

The incidence of AF was 5% in this cohort. PWD, PR and QT intervals significantly predicted AF and are simple electrocardiographic markers for identifying potential at-risk patients.

Electrocardiographic evidence of abnormal atrial phenotype in Brugada syndrome

BACKGROUND

Brugada syndrome (BrS) is an inherited ion channelopathy that may predispose affected individuals to atrial cardiomyopathy. We tested the hypothesis that BrS patients have higher degrees of atrial electrophysiological abnormalities compared to controls, and these can be reflected by changes in P-wave parameters determined on the electrocardiogram (ECG).

METHODS

This was a single-center retrospective study comparing BrS patients to age- and gender-matched control subjects. Mean P-wave duration (PWD_mean), maximum PWD (PWD_max) and minimum PWD (PWD_min), P-wave dispersion (PWD_max - PWD_min), and P-wave terminal force in V1 (PTFV1) were measured. PWD_max ≥ 120 ms, in the presence and absence of biphasic P-waves in the inferior leads, were termed advanced and partial inter-atrial block (IAB), respectively.

RESULTS

The proportion of IAB was significantly higher in BrS patients (28/51; 55%) than in control subjects (14/51; 27%; Fisher's Exact test; P < 0.01). Advanced IAB was observed in two BrS patients but none of the control subjects (P = 0.50). Compared to controls, BrS patients showed higher PWD_mean (107 [98-113] vs. 97 [90-108] ms; KWANOVA, P < 0.01), PWD_max (123 [110-132] vs. 113 [107-121] ms; P < 0.001) but statistically indistinguishable PWD_min (82 [72-92] vs. 77 [69-85]; P = 0.09), and P-wave dispersion (38 [26-52] vs. 37 [23-45] ms; P = 0.14). PTFV1 was significantly higher in BrS patients than in control subjects (24 [0-40] vs. 0 [0-27] mm.ms; P < 0.05).

CONCLUSION

Atrial conduction abnormalities are frequently observed in BrS. These patients may require monitoring for future development of atrial fibrillation and stroke.