The Author's reply
- Correspondence to Dr Edward P Gerstenfeld, Associate Professor of Medicine, University of California, San Francisco, MUE-4th Floor, 500 Parnassus Ave, San Francisco, CA 94143, USA;
- Atrial fibrillation
- radiofrequency catheter ablation
- ventricular tachycardia
- atrial flutter
The Author's reply Dr Ward feels that I have given ‘short shrift’ to the cryoballoon in my commentary on the National Institute of Health and Clinical Excellence (NICE) guidelines for laser balloon ablation.1 2 I certainly welcome Dr Wards' comments and summary of cryoballoon efficacy, but feel a few additional comments are necessary.
First, Dr Ward points out that my comments may be biased because I have a ‘vested interest’ in the laser balloon. It should be noted that while I have received an investigator initiated research grant to perform preclinical work with the laser balloon (as declared in the editorial), I have no other consulting role with the company nor have I received any payment for work with the company. As a physician who spends a large part of my time performing atrial fibrillation (AF) ablations, my main goal is to help develop any new technology that may improve the safety, efficacy and speed of catheter ablation. Preclinical work often requires industry support. I have also received support for preclinical work from Medtronic, manufacturer of the cryoballoon. As discussed in the editorial, I think it is time we move beyond point-to-point ablation for achieving pulmonary vein isolation, and such an effort often requires collaboration between physicians and industry to advance new technologies. It is not surprising that in the meta-analysis referenced by Dr Ward as proof of the efficacy of the cryoballoon,3 the senior author disclosed that he is a consultant to Medtronic. It is important to recognise that these conflicts exist and may affect our perceptions and advocacy, and that they be acknowledged to the readers of any journal.
Dr Ward states in quotes that I dismiss the cryoballoon as ‘having problems’—but I cannot find such a quote in my commentary. I was asked to write a commentary on the NICE guidelines for laser balloon ablation, not the cryoballoon. As an investigator in the STOP-AF trial,2 I certainly agree that the ease of use of the cryoballoon and superiority over anti-arrhythmic drugs is impressive. However, as clinicians we must be realistic about every new therapy, and some of Dr Ward's comments appear pollyannaish. Dr Ward points out that the efficacy of the cryoballoon was ‘over 70% discounting recurrences inside a 3-month blanking period.’ However it should be recognised that although the success rate in STOP-AF was 70%, this included a 19% redo rate using catheter ablation during the blanking period. So the true single procedure success rate was approximately 60% at 1-year, similar but not superior to that of standard catheter ablation.4 One of the major findings of the STOP-AF trial was that phrenic nerve palsy and pulmonary vein stenosis can occur with the cryoballoon; these outcomes have led to modifications in the procedural techniques that have led to a dramatic decrease in the incidence of these events among experienced investigators. I have been using the cryoballoon clinically for treating paroxysmal AF, and have been pleased with the efficacy, speed and safety of the 28 mm cryoballoon.
The laser balloon is a self-contained system that is straightforward to use and also does not require additional mapping systems. The laser component of the balloon is internal to the system and therefore no special laser certification is needed for clinical use in USA. One would assume that if it is eventually approved for use in USA, there would be similar training to that currently mandated for the cryoballoon.
The hope among all electrophysiologists is that a balloon technology designed specifically for pulmonary vein (PV) isolation will become available that is simple, safe, fast, and results in PV isolation in >95% of patients. Only then will we know the true efficacy of PV isolation for treating AF. The current iterations of both the cryoballoon and laser balloon are unlikely to achieve this mark. It is only by collaborating with industry and performing prospective randomised trials that we will continue to move the field of AF ablation ‘into the light’.
Linked article 301956.
Competing interests None.
Patient consent Obtained.
Provenance and peer review Commissioned; internally peer reviewed.