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Fulltext Drug-induced Brugada syndrome

Yap YG, Behr ER, Camm AJ

Europace, 2009 Aug;11(8):989-94.
PMID: 19482855 DOI: 10.1093/europace/eup114

Brugada syndrome is an inherited cardiac arrhythmia condition characterized by (i) coved ST-elevation and J point elevation of at least 2 mm in at least two of the right precordial ECG leads (V1-V3) and (ii) ventricular arrhythmias, syncope, and sudden death. Patients with Brugada syndrome or suspected mutation carriers can have normal ECG recordings at other times. In these cases, a diagnostic challenge with a sodium channel blocker such as ajmaline, flecainide, or pilsicainide may induce the full-blown type 1 ECG pattern and support the diagnosis. However, recently, many other pharmacological agents not related to class I anti-arrhythmic agents have been reported to induce Brugada ECG patterns including tricyclic antidepressants, fluoxetine, lithium, trifluoperazine, antihistamines, and cocaine. As published reports of the drug-induced Brugada sign have become increasingly prevalent, there is growing interest in the mechanisms responsible for this acquired ECG pattern and its clinical significance. It is possible that drug-induced Brugada syndrome may be due to an individual susceptibility that favours drug-induced ECG abnormalities, possibly as a result of an increase in a latent ion channel dysfunction similar to that in drug-induced long QT syndrome. However, further evidence is needed to confirm this postulation. In this paper, we will review the cases and evidence of drug-induced Brugada syndrome reported in the literature.
Fulltext Cardiac Potassium Channels: Physiological Insights for Targeted Therapy

Jeevaratnam K, Chadda KR, Huang CL, Camm AJ

J Cardiovasc Pharmacol Ther, 2018 03;23(2):119-129.
PMID: 28946759 DOI: 10.1177/1074248417729880

The development of novel drugs specifically directed at the ion channels underlying particular features of cardiac action potential (AP) initiation, recovery, and refractoriness would contribute to an optimized approach to antiarrhythmic therapy that minimizes potential cardiac and extracardiac toxicity. Of these, K+ channels contribute numerous and diverse currents with specific actions on different phases in the time course of AP repolarization. These features and their site-specific distribution make particular K+ channel types attractive therapeutic targets for the development of pharmacological agents attempting antiarrhythmic therapy in conditions such as atrial fibrillation. However, progress in the development of such temporally and spatially selective antiarrhythmic drugs against particular ion channels has been relatively limited, particularly in view of our incomplete understanding of the complex physiological roles and interactions of the various ionic currents. This review summarizes the physiological properties of the main cardiac potassium channels and the way in which they modulate cardiac electrical activity and then critiques a number of available potential antiarrhythmic drugs directed at them.
The New CHEST Guidelines on Antithrombotic Therapy for Atrial Fibrillation Should Consider Recent Data on Rivaroxaban

Kim YH, Shim J, Tsai CT, Wang CC, Vilela G, Muengtaweepongsa S, et al.

Chest, 2019 06;155(6):1309-1311.
PMID: 31174652 DOI: 10.1016/j.chest.2019.03.036
Fulltext XANAP: A real-world, prospective, observational study of patients treated with rivaroxaban for stroke prevention in atrial fibrillation in Asia

Kim YH, Shim J, Tsai CT, Wang CC, Vilela G, Muengtaweepongsa S, et al.

J Arrhythm, 2018 Aug;34(4):418-427.
PMID: 30167013 DOI: 10.1002/joa3.12073

BACKGROUND: ROCKET AF and its East Asian subanalysis demonstrated that rivaroxaban was non-inferior to warfarin for stroke/systemic embolism (SE) prevention in patients with non-valvular atrial fibrillation (NVAF), with a favorable benefit-risk profile. XANAP investigated the safety and effectiveness of rivaroxaban in routine care in Asia-Pacific.
METHODS: XANAP was a prospective, real-world, observational study in patients with NVAF newly starting rivaroxaban. Patients were followed at ~3-month intervals for 1 year, or for ≥30 days after permanent discontinuation. Primary outcomes were major bleeding events, adverse events (AEs), serious AEs and all-cause mortality; secondary outcomes included stroke/SE. Major outcomes were adjudicated centrally.
RESULTS: XANAP enrolled 2273 patients from 10 countries: mean age was 70.5 years and 58.1% were male. 49.8% of patients received rivaroxaban 20 mg once daily (od), 43.8% 15 mg od and 5.9% 10 mg od. Mean treatment duration was 296 days, and 72.8% of patients had received prior anticoagulation therapy. Co-morbidities included heart failure (20.1%), hypertension (73.6%), diabetes mellitus (26.6%), prior stroke/non-central nervous system SE/transient ischemic attack (32.8%) and myocardial infarction (3.8%). Mean CHADS2, CHA2DS2-VASc and HAS-BLED scores were 2.3, 3.7 and 2.1, respectively. The rates (events/100 patient-years [95% confidence interval]) of treatment-emergent major bleeding, stroke and all-cause mortality were 1.5 (1.0-2.1), 1.7 (1.2-2.5) and 2.0 (1.4-2.7), respectively. Persistence was 66.2% at the study end.
CONCLUSIONS: The real-world XANAP study demonstrated low rates of stroke and bleeding in rivaroxaban-treated patients with NVAF from Asia-Pacific. The results were consistent with the real-world XANTUS study and ROCKET AF.