Paradoxical worsening of an arrhythmia due to antiarrhythmics

• Published in: Heart (British Cardiac Society) Vol. 109; no. 20; pp. 1515 - 1576
• Main Authors: Lopez-Lizarraga, Miguel Angel, Sánchez-Amaya, David Jacobo, Godinez-Córdova, Luis Benjamin
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Cardiovascular Society 01.10.2023; BMJ Publishing Group LTD
• Subjects: arrhythmias, cardiac; atrial flutter; Cardiac arrhythmia; Emergency medical care; Image challenge; Morphology; Pacemakers; Mexico
• ISSN: 1355-6037; 1468-201X
• DOI: 10.1136/heartjnl-2023-323078

The initial ECG showed a regular wide QRS tachycardia with left-bundle branch block morphology, a QRS duration of 160 ms, QS in V1–V3 and a ventricular activation time of 80 ms. The notched R wave in V5–V6 and an atrioventricular (AV) conduction rate of 1:1 are consistent with VT according to the Brugada criteria. Aberrant ventricular depolarisation patterns leading to a regular wide-complex tachycardia, which can be mistaken for VT, are commonly observed due to the high ventricular rates.2 3 The present case emphasises the rare and serious adverse effects of propafenone, which are well-documented, and underscores the significance of prescribing an AV nodal blocking agent prior to propafenone initiation in patients with atrial fibrillation and AFL. The Corresponding Author has the right to grant on behalf of all authors and does grant on behalf of all authors, an exclusive licence (or non-exclusive for government employees) on a worldwide basis to the BMJ Publishing Group Ltd (BMJPGL) and its Licensees to permit this article (if accepted) to be published in Heart editions and any other BMJPGL products to exploit all subsidiary rights.