Author + information
- Received October 29, 2018
- Revision received January 2, 2019
- Accepted January 31, 2019
- Published online April 15, 2019.
- Christopher C. Cheung, MDa,
- Greg Mellor, MDb,c,
- Marc W. Deyell, MD, MSc(Epi)a,
- Bode Ensam, MBBSb,c,
- Velislav Batchvarov, MDb,c,
- Michael Papadakis, MDb,c,
- Jason D. Roberts, MD, MASd,
- Richard Leather, MDe,
- Shubhayan Sanatani, MDf,
- Jeffrey S. Healey, MDg,
- Vijay S. Chauhan, MDh,
- David H. Birnie, MB, ChBi,
- Jean Champagne, MDj,
- Paul Angaran, MDk,
- George J. Klein, MDd,
- Raymond Yee, MDd,
- Christopher S. Simpson, MDl,
- Mario Talajic, MDm,
- Martin Gardner, MDn,
- John A. Yeung-Lai-Wah, MDa,
- Santabhanu Chakrabarti, MDa,
- Zachary W. Laksman, MD, MSca,
- Sanjay Sharma, MDb,c,
- Elijah R. Behr, MDb,c and
- Andrew D. Krahn, MDa,∗ ()
- aDivision of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada
- bCardiology Clinical Academic Group, St. George’s University Hospitals NHS Foundation Trust, London, United Kingdom
- cInstitute of Molecular and Clinical Sciences, St. George’s University of London, London, United Kingdom
- dSection of Cardiac Electrophysiology, Division of Cardiology, Western University, London, Ontario, Canada
- eDivision of Cardiology, Royal Jubilee Hospital, Victoria, British Columbia, Canada
- fChildren’s Heart Centre, Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
- gDivision of Cardiology, McMaster University, Hamilton, Ontario, Canada
- hToronto General Research Institute, University Health Network, Toronto, Ontario, Canada
- iUniversity of Ottawa Heart Institute, University of Ottawa, Ottawa, Ontario, Canada
- jInstitut Universitaire de Cardiologie et Pneumologie de Québec, Université Laval, Québec City, Québec, Canada
- kDivision of Cardiology, St. Michael’s Hospital, University of Toronto, Toronto, Ontario, Canada
- lDivision of Cardiology, Queen’s University, Kingston, Ontario, Canada
- mInstitut de Cardiologie de Montréal, Département of Médecine, Université de Montréal, Montréal, Québec, Canada
- nDivision of Cardiology, Dalhousie University, Halifax, Nova Scotia, Canada
- ↵∗Address for correspondence:
Dr. Andrew Krahn, Heart Rhythm Vancouver, 211-1033 Davie Street, Vancouver, British Columbia V6E 1M7, Canada.
Objectives The authors studied the response rates and relative sensitivity of the most common agents used in the sodium-channel blocker (SCB) challenge.
Background A type 1 Brugada electrocardiographic pattern precipitated by an SCB challenge confers a diagnosis of Brugada syndrome.
Methods Patients undergoing an SCB challenge were prospectively enrolled across Canada and the United Kingdom. Patients with no prior cardiac arrest and family histories of sudden cardiac death or Brugada syndrome were included.
Results Four hundred twenty-five subjects underwent SCB challenge (ajmaline, n = 331 [78%]; procainamide, n = 94 [22%]), with a mean age of 39 ± 15 years (54% men). Baseline non–type 1 Brugada ST-segment elevation was present in 10%. A total of 154 patients (36%) underwent signal-averaged electrocardiography, with 41% having late potentials. Positive results were seen more often with ajmaline than procainamide infusion (26% vs. 4%, p < 0.001). On multivariate analysis, baseline non–type 1 Brugada ST-segment elevation (odds ratio [OR]: 6.92; 95% confidence interval [CI]: 3.15 to 15.2; p < 0.001) and ajmaline use (OR: 8.76; 95% CI: 2.62 to 29.2; p < 0.001) were independent predictors of positive results to SCB challenge. In the subgroup undergoing signal-averaged electrocardiography, non–type 1 Brugada ST-segment elevation (OR: 9.28; 95% CI: 2.22 to 38.8; p = 0.002), late potentials on signal-averaged electrocardiography (OR: 4.32; 95% CI: 1.50 to 12.5; p = 0.007), and ajmaline use (OR: 12.0; 95% CI: 2.45 to 59.1; p = 0.002) were strong predictors of SCB outcome.
Conclusions The outcome of SCB challenge was significantly affected by the drug used, with ajmaline more likely to provoke a type 1 Brugada electrocardiographic pattern compared with procainamide. Patients undergoing SCB challenge may have contrasting results depending on the drug used, with potential clinical, psychosocial, and socioeconomic implications.
This study was supported by the Heart and Stroke Foundation of Canada (G-13-0002775 and G-14-0005732), Cardiac Risk in the Young, and the Robert Lancaster Memorial fund sponsored by McColl’s RG. The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
All authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the JACC: Clinical Electrophysiology author instructions page.
- Received October 29, 2018.
- Revision received January 2, 2019.
- Accepted January 31, 2019.
- 2019 American College of Cardiology Foundation
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