Letters to the Editor
Atrial fibrillation – QT interval and catheter ablation
- Linda Mann, Paul Salmon, Deep Chandh Raja
- Aust Prescr 2020;43:65
- 1 April 2020
- DOI: 10.18773/austprescr.2020.018
ISSUE 2 APRIL
Letter to the Editor
The recent article about atrial fibrillation1 states that the QT interval should be closely monitored, and sotalol is relatively contraindicated in patients with chronic renal impairment. How do we monitor QT interval in atrial fibrillation when it is not measurable?
Linda Mann
General practitioner, YourDoctors, Sydney
Letter to the Editor
Great article on atrial fibrillation1, but why is there no mention of cryoablation when radiofrequency ablation was mentioned?
Paul Salmon
Radiologist, Sydney
Author' repsonse
Deep Chandh Raja, one of the authors of the article, comments:
In response to Linda Mann’s query, we suggest measuring the QT interval in atrial fibrillation as an average over five ventricular beats. This has been shown to correspond very closely to the QT interval of the same patients in sinus rhythm, when corrected for heart rate.2 A heart rate correction formula (e.g. Bazett’s) should be used, however there is no robust evidence to show superiority of one particular formula over the other.2
With regards to the query from Paul Salmon about catheter ablation, there are different sources of energy for catheter ablation – radiofrequency energy, cryotherapy and pulsed field ablation.3 Radiofrequency energy continues to remain the widely practised mode of catheter ablation, although radiofrequency energy and cryotherapy have similar efficacy rates. Pulsed field ablation or electroporation has recently shown promising results in the first-in-human trials.3
References
- McCallum CJ, Raja DC, Pathak RK. Atrial fibrillation: an update on management. Aust Prescr 2019;42;186-91.
- Tooley J, Ouyang D, Hadley D, Turakhia M, Wang P, Ashley E, et al. Comparison of QT interval measurement methods and correction formulas in atrial fibrillation. Am J Cardiol 2019;123:1822-7.
- Reddy VY, Neuzil P, Koruth JS, Petru J, Funosako M, Cochet H, et al. Pulsed field ablation for pulmonary vein isolation in atrial fibrillation. J Am Coll Cardiol 2019;74:315-26.
The Editorial Executive Committee welcomes letters, which should be less than 250 words. Before a decision to publish is made, letters which refer to a published article may be sent to the author for a response. Any letter may be sent to an expert for comment. When letters are published, they are usually accompanied in the same issue by any responses or comments. The Committee screens out discourteous, inaccurate or libellous statements. The letters are sub-edited before publication. Authors are required to declare any conflicts of interest. The Committee's decision on publication is final.
Linda Mann
General practitioner, YourDoctors, Sydney
Paul Salmon
Radiologist, Sydney
Deep Chandh Raja
Cardiologist, Cardiac Electrophysiology Unit, Department of Cardiology, Canberra Hospital and Health Services, Australian National University
