title: Two Cases of LQT Syndrome with Malignant Syncope after Switch from Propranolol to Bisoprolol.
abstract: Propranolol in slow-release form has been the first-line treatment in long QT (LQT) until it was withdrawn from the market. We describe two cases where a switch to bisoprolol resulted in worsening of arrhythmia control: A man with LQT2, asymptomatic on propranolol, experienced syncope after switching to bisoprolol 5 mg daily. He switched back to propranolol and has remained asymptomatic during subsequent 12 months. A man with classical Jervell Lange-Nielsen syndrome, previous gangliectomy, and ICD implantation, switched to bisoprolol 5 mg daily. Four months later he experienced a tachycardia storm. He switched back to propranolol and has remained free from arrhythmias during subsequent 12 months.
authors.affiliation: Heart Centre, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden.
authors.forename: Milos
authors.initials: M
authors.lastname: Kesek
authors.affiliation: Department of Clinical Sciences, Pediatrics, Umeå University, Umeå, Sweden.
authors.forename: Annika
authors.initials: A
authors.lastname: Rydberg
authors.affiliation: Heart Centre, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden.
authors.forename: Steen M
authors.initials: SM
authors.lastname: Jensen
mesh_terms: D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000009:adverse effects; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000009:adverse effects; D017298:Bisoprolol / Q000008:administration & dosage* / Q000009:adverse effects*; D004334:Drug Administration Schedule; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis / Q000188:drug therapy*; D008297:Male; D011433:Propranolol / Q000008:administration & dosage* / Q000009:adverse effects*; D013575:Syncope / Q000139:chemically induced* / Q000175:diagnosis / Q000517:prevention & control; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000889:Anti-Arrhythmia Agents; D000959:Antihypertensive Agents; D011433:Propranolol; D017298:Bisoprolol
keywords: beta-blocker therapy; bisoprolol; long QT; pharmacology; propranolol