title: Flecainide Toxicity: A Case Report and Systematic Review of its Electrocardiographic Patterns and Management.
abstract: In the setting of flecainide toxicity, supraventricular tachycardia can manifest as a bizarre right or left bundle branch block, sometimes with a northwest axis, and can easily be mistaken for ventricular tachycardia leading to inappropriate therapy. We conducted a comprehensive literature review for cases of flecainide toxicity. We found 21 articles of flecainide toxicity in adult patients in which 22 ECG tracings were published. In patients with flecainide toxicity and QRS duration ≤ 200 ms, the ECGs were more likely to show RBBB, visible P waves (p = 0.03), and shorter QT (p = 0.02) and QTc intervals (p = 0.004). With QRS duration > 200 ms, the ECGs were more likely to show LBBB, loss of P waves, a northwest axis (p = 0.01), and longer QT and QTc intervals. Deaths were reported only in patients with QRS duration >200 ms, and the outcome of death or requirement for mechanical circulatory support was more prevalent in patients with a QRS duration > 200 ms [2/13 (15.4 %) vs. 6/10 (60 %), p = 0.04]. In patients with access to the medication, flecainide toxicity should be suspected with: (1) broad QRS, (2) RBBB morphology with QRS ≤ 200 ms; RBBB or LBBB morphology with QRS ≥ 200 ms (3) HR out of proportion to the degree of hemodynamic instability. The duration of the QRS interval is prognostic, with mortality and the requirement for mechanical circulatory support being more common in patients with a QRS > 200 ms.
authors.affiliation: Division of Cardiology, Thomas Jefferson University Hospital, 925 Chestnut St. Mezzanine, Philadelphia, PA, 19107, USA. Michael.Valentino@jefferson.edu.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Valentino
authors.affiliation: Division of Internal Medicine, Thomas Jefferson University Hospital, 833 Chestnut Street Suite 701, Philadelphia, PA, 19107, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Panakos
authors.affiliation: Division of Internal Medicine, Thomas Jefferson University Hospital, 833 Chestnut Street Suite 701, Philadelphia, PA, 19107, USA.
authors.forename: Loheetha
authors.initials: L
authors.lastname: Ragupathi
authors.affiliation: Division of Internal Medicine, Thomas Jefferson University Hospital, 833 Chestnut Street Suite 701, Philadelphia, PA, 19107, USA.
authors.forename: Janna
authors.initials: J
authors.lastname: Williams
authors.affiliation: Division of Cardiology, Thomas Jefferson University Hospital, 925 Chestnut St. Mezzanine, Philadelphia, PA, 19107, USA.|Division of Internal Medicine, Thomas Jefferson University Hospital, 833 Chestnut Street Suite 701, Philadelphia, PA, 19107, USA.
authors.forename: Behzad B
authors.initials: BB
authors.lastname: Pavri
mesh_terms: D000889:Anti-Arrhythmia Agents / Q000009:adverse effects*; D019468:Disease Management; D004562:Electrocardiography / Q000187:drug effects / Q000639:trends; D005424:Flecainide / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017693:Sodium Bicarbonate / Q000008:administration & dosage; D017180:Tachycardia, Ventricular / Q000139:chemically induced* / Q000188:drug therapy* / Q000503:physiopathology
chemical_list: D000889:Anti-Arrhythmia Agents; D017693:Sodium Bicarbonate; D005424:Flecainide
keywords: Electrocardiogram; Flecainide; Toxicity/overdose