Risk stratification in Brugada syndrome remains a clinical challenge because the event rate is low but the presenting symptom is often cardiac arrest (CA). We review the data on risk stratification. ...A history of CA or malignant syncope is a strong predictor of spontaneous ventricular fibrillation (VF), whereas the prognostic value of a history of familial sudden death and the presence of a SCN5A mutation are less well defined. On the electrocardiogram, the presence of spontaneous type I electrocardiogram increases the risk for VF in all studies, whereas the presence of fragmented QRS complexes and early repolarization correlates with increased risk in several studies. Signal-averaged techniques using late potentials and microscopic T-wave alternans show some promising results in small studies that need to be confirmed. The value of electrophysiologic studies for predicting spontaneous VF remains controversial, and this includes programmed stimulation protocols that avoid a third extrastimuli or stimulation from the right ventricular outflow. Risk prediction is particularly challenging in children and women.
Means for distinguishing the very common "benign early repolarization" from the very rare but malignant form are needed. Recently, the presence of early repolarization with "horizontal ST segment" ...was found to predict arrhythmic death during long-term follow-up in a large population study. We therefore speculated that the combination of "J waves with horizontal ST segment" would correlate with a history of idiopathic ventricular fibrillation (VF) better than the mere presence of J waves.
To determine whether the morphology of the ST segment adds diagnostic value to the mere presence of J waves in a case-control series of idiopathic VF.
We reanalyzed our case-control study showing that the presence of J waves strongly correlates with a history of idiopathic VF among 45 patients with this disorder, 124 controls matched for age and gender ("matched-control" group), and 121 young athletes. This time we focused only on those patients with J waves and graded their ST-segment morphology as either "horizontal" or "ascending" according to predefined criteria.
The presence of J waves was associated with a history of idiopathic VF with an odds ratio of 4.0 (95% confidence intervals = 2.0-7.9), but having both J waves and horizontal ST segment yielded an odds ratio of 13.8 (95% confidence intervals = 5.1-37.2) for having idiopathic VF.
We report, for the first time, that the combination of J waves with horizontal/descending ST segment improved our ability to distinguish patients with idiopathic VF from controls matched by gender and age.
There is an urgent need to identify electrocardiographic characteristics that differentiate the “benign early repolarization pattern” from “malignant early repolarization.” In a previous paper, we ...considered the different electrocardiographic elements of the early repolarization pattern and analyzed how they confer important prognostic information. In the present article, we review more recent information regarding the importance of the contour of the ST segment, with special emphasis on the currently termed malignant form and its value for risk stratification in early repolarization.
The presence of J waves and ST-segment elevation on the electrocardiogram (ECG), jointly termed "the early repolarization pattern," has traditionally been considered a marker of "good health." ...However, recent case control series and long-term population studies have established a statistically significant association between this ECG pattern and an increased risk for arrhythmic death. This finding has raised concern among physicians, who now are asked to estimate the "arrhythmic risk" following the incidental discovery of J waves on routine ECG. Therefore, we review the literature linking early repolarization with arrhythmic risk to place this "fear of J waves" in the right perspective. We found five case control studies (involving 331 patients with idiopathic ventricular fibrillation VF and 8,649 controls). All of these studies showed that J waves, particularly of large amplitude and recorded in multiple leads, are more prevalent among patients with idiopathic VF. We also found three large population studies (involving >17,000 individuals) looking at the prognostic value of early repolarization. Two of these studies showed that the presence of J waves >2 mm in amplitude in asymptomatic adults is associated with a threefold increased of arrhythmic death during very long-term follow-up. Individuals with J waves do have some degree of increased dispersion of repolarization that places them at increased risk for arrhythmic death, but only in the presence of additional proarrhythmic factors or triggers. A sensible approach for the asymptomatic patient with J waves is proposed.
Objectives The aim of this study was to determine the availability of quinidine throughout the world. Background Quinidine is the only oral medication that is effective for preventing ...life-threatening ventricular arrhythmias due to Brugada syndrome and idiopathic ventricular fibrillation. However, because of its low price and restricted indication, this medication is not marketed in many countries. Methods We conducted a survey of the availability of quinidine by contacting professional medical societies and arrhythmia specialists worldwide. Physicians were e-mailed questionnaires requesting information concerning the quinidine preparation available at their hospital. We also requested information concerning cases of adverse arrhythmic events resulting from unavailability of quinidine. Results A total of 273 physicians from 131 countries provided information regarding the availability of quinidine. Quinidine was readily available in 19 countries (14%), not accessible in 99 countries (76%), and available only through specific regulatory processes that require 4 to 90 days for completion in 13 countries (10%). We were able to gather information concerning 22 patients who had serious arrhythmias probably related (10 cases) or possibility related (12 cases) to the absence of quinidine, including 2 fatalities possibly attributable to the unavailability of quinidine. Conclusions The lack of accessibility of quinidine is a serious medical hazard at the global level.
Fever is known to unmask the Brugada pattern on the electrocardiogram (ECG) and trigger ventricular arrhythmias in patients with Brugada syndrome. Genetic studies in selected cases with fever-induced ...Brugada pattern have identified disease-causing mutations. Thus, "fever-induced Brugada" is a recognized clinical entity. However, its prevalence has not been systematically evaluated.
The purpose of this study was to assess the prevalence of Brugada pattern in consecutive patients with fever.
ECGs of patients with fever admitted to the emergency department were evaluated for the presence of Brugada pattern and compared with ECGs of consecutive nonfebrile patients.
ECGs of 402 patients with fever and 909 without were evaluated. Type I Brugada pattern was 20 times more common in the febrile group than in the afebrile group (2% vs. 0.1%, respectively, P = .0001). All patients with fever-induced type I Brugada pattern were asymptomatic and remained so during 30 months of follow-up.
Type I Brugada pattern is definitively more common among patients with fever, suggesting that asymptomatic Brugada syndrome is more prevalent than previously estimated.
Aims:
Assessing the effectiveness of novel bio-sensing technology (CardiacSense), for accuracy and reliability of automatic detection of life-threatening arrhythmias.
Methods and Results:
This ...prospective study consisted of Eighteen patients (13 males and 5 females, mean age 59.4 ± 21.3 years) undergoing induction of ventricular tachycardia/fibrillation or provocation of transient ventricular asystole. We tested the detection of provoked ventricular arrhythmias by a wrist-worn watch-like device which uses photoplethysmography (PPG) technology to detect the cardiac rhythm. We used simultaneous electrocardiographic (ECG) recordings as gold standard for arrhythmia definition and confirmation of beat-to-beat detection. A total of 1,527 QRS complexes were recorded simultaneously by ECG and PPG. The overall correlation between the ECG (R-R intervals) and the PPG (G-G intervals) was high, with a correlation coefficient of R = 0.949 (
p
< 0.001). The device accurately detected all events of mimicked life endangering arrhythmias, including five events of transient (adenosine-induced) ventricular asystole as well as seven episodes of monomorphic ventricular tachycardia and 6 events of ventricular fibrillation.
Conclusion:
This proof-of-concept study suggests that wearable devices using PPG technology, currently used to detect atrial fibrillation, may also have a role as automatic detectors of life-threatening arrhythmias.
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