Cardiac Rhythm Management
Articles Articles 2013 October

COMMENTARY FROM THE SECTION EDITOR - The Need to Innovate

SAMUEL J. ASIRVATHAM, MD, FHRS, FACC

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ATRIAL FIBRILLATION 

 

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The Need to Innovate

Innovation has been described in some instances as a choice or luxury afforded by underlying societal success so as to make what is already good even better. Innovation in some circumstances, however, represents a requirement to prevent recognized impending failure with no apparent recourse or reversal. In this issue of Innovations in Cardiac Rhythm Management, Gilligan et al report their encouraging findings of an innovative convergent procedure that combines endocardial and epicardial approaches. They use a novel tool, the development of which acknowledges the importance of optimizing contact and choosing the right ablation technique for epicardial approaches without the need for pericardial reflection dissection. 1

As they state in the introduction to their report, given the incredibly high prevalence of atrial fibrillation (AF) and the incremental $15,000 per year cost per patient, AF is not just a drain on health-care resources but is the straw that breaks the camel’s back. 1,2 The only choice that can reasonably remain is to simply not treat AF or to recognize explicitly where we have presently failed and where we urgently need to innovate.

Facts

Unacceptable recurrence following persistent AF ablation

Gilligan et al state as fact in their introduction the reality of AF ablation today. While we continue to enjoy reasonable success in relieving the patient’s symptoms of paroxysmal AF, by the yardstick of being AF-free without antiarrhythmic agents in the long term, we fail in persistent AF. 2,3 Initially we thought our failures were because we did not ablate in the right area or in the right way, but now we accept that we simply do not know a way of curing persistent AF.

Linear and circumferential ablation

Gilligan et al left linear ablation done endocardially to the discretion of the operator. This was an acceptance of the fact that no clear guideline can be made in this regard. We do not know the patients that benefit from linear ablation, nor do we know the patients who are more likely to get proarrhythmia from incomplete linear ablations.

Limitations of epicardial ablation

Apparent in the construct of the study reported in their paper is the acceptance of the fact that certain regions that may require ablation are not possible to reach with an epicardial approach, particularly without extensive pericardial reflection dissection. Assessment of exit and entrance block in pulmonary veins is also not straightforward from a pure epicardial approach, and thus the need for convergent procedures.

Endocardial ablation alone is not ideal

With their novel approach to optimized contact in lesion formation epicardially is implicit acceptance of the fact that uniform, gap-free, endocardial ablation, particularly anterior to the pulmonary vein is not easy, and thus the need for convergent procedures.

The unexplained

Always and forever

We do not know at present how we can on a consistent basis create gap-free, transmural lesions that are permanent. Recurrence of conduction across lines and circumferential lesions appears to parallel the increasing recurrence rates with longer term follow-up. While it is possible that convergent procedures with optimal transmural lesion creation may partly solve this problem, the reasons for recurrence are not yet established.

Duration and method of follow-up

Another remaining and vexing problem is how we define and document success rates with AF ablation. 4 The authors report 1-year follow-up, while we know the unacceptably high recurrence rates are more apparent with longer term follow-up. The blanking period following ablation, the use of antiarrhythmic agents including amiodarone, which may have an effect for several weeks or months following the discontinuation, make shorter term follow-up problematic. The authors used 72-h Holter monitors and electrocardiograms, as well as reported patient symptoms, to know whether they were successful. Documentation with continuous monitoring of all atrial arrhythmias, including brief, organized atrial dysrhythmias as well as AF, has taught us that shorter term monitoring tends in some instances to grossly overestimate success rate. The problem is complex. Another unknown is whether asymptomatic short duration AF truly represents a target for elimination or can be left untreated.

AF and stroke risk

We now know that AF and stroke represent an epiphenomenon that is not always a causal relationship. While we develop better ablative methods (convergent or otherwise) in creating atrial myocardial lesions, the impact on stroke is unknown. Atrial dyssynchrony, myocardial scar, and left atrial appendage dysfunction or isolation as a result of ablation may paradoxically increase stroke risk despite improvements in the rate of maintaining sinus rhythm. 5

Summary

If we combine the fact that AF is an unacceptable burden on our patients and, by virtue of its impact on health-care cost, a burden on our society and the fact that we do not know how to cure AF, we can clearly visualize another fact: innovation is a need and not a choice for AF management. Innovation for catheter design, types of procedures, new types of collaborative efforts, assessment of impact on stroke and cognitive function outcomes, and achieving permanence of our results remain pressing needs. This realization should be accepted as fact by electrophysiologists, educators, and training program directors (so as to incorporate innovation in the curriculum), heart rhythm societies, and the Food and Drug Administration. As with so many problems that face individuals in society, acceptance of the problem and the need for new solutions is a critical first step …

SAMUEL J. ASIRVATHAM, MD, FHRS, FACC
E-mail: asirvatham.samuel@mayo.edu
Consultant, Division of Cardiovascular Diseases and Internal Medicine
Division of Pediatric Cardiology
Professor of Medicine and Pediatrics
Mayo Clinic College of Medicine
Rochester, MN

References

  1. Gilligan DM, Joyner CA, Bundy GM. Multidisciplinary collaboration for the treatment of atrial fibrillation: Convergent procedure outcomes from a single center. J Innov Cardiac Rhythm Manage 2013; 1–8.
  2. Crandall MA, Bradley DJ, Packer DL, Asirvatham SJ. Contemporary management of atrial fibrillation: update on anticoagulation and invasive management strategies. Mayo Clin Proc 2009; 84:643–662.
  3. Weerasooriya R, Khairy P, Litalien J, et al. Catheter ablation for atrial fibrillation: are results maintained at 5 years of follow-up? J Am Coll Cardiol 2011; 57:160–166.
  4. Asirvatham SJ, Packer DL. Managing atrial fibrillation: catheter ablation or antiarrhythmic therapy? Circ Arrhythm Electrophysiol 2009; 2:599–602.
  5. Syed FF, Asirvatham SJ. Left atrial appendage as a target for reducing strokes: justifiable rationale? Safe and effective approaches? Heart Rhythm 2011; 8:194–198.

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