Beyond Refining Indications – Improve Therapies

An ACCF/AHA/HRS focused update of the implantable device guidelines was published in January 2013.¹ The document is a 79-page update that includes modern indications for pacemakers, implantable defibrillators, and cardiac resynchronization pacing therapy, and has nearly 600 references. The contents of the update would be difficult to summarize on this page. However, there is a compelling segment of the document that merits attention. At the end of the manuscript, there is a list of what the writing committee considers as areas in need of further research. Their list is paraphrased below:

1. Optimize access to device therapy for all eligible populations.
2. Improve risk stratification for primary prevention.
3. Improve identification of potential responders to CRT.
4. Identify new groups of patients who could benefit from device therapy.
5. Identify patients who do not need defibrillator generator replacement at the time of battery depletion.
6. Further explore cost-effectiveness.
7. Develop guidelines for remote monitoring.
8. Improve reliability and longevity of leads and generators and ensure discovery of performance issues. 
9. Represent the elderly more in clinical trials.
10. Determine the influence of age on complication rates and risk/benefit ratio for device implantation.
11. Determine effect of left ventricular stimulation in patients with normal ventricular function. 
12. Evaluate the need for pacing after myocardial infarction.
13. Define outcomes in general practice compared with clinical trials.
14. Develop guidelines for device management in patients with terminal illness. 
15. Define the role of ICDs in primary prevention for children. 
16. Investigate the efficacy of biventricular pacing in children.

This above list of potential areas of investigation is important given that it was written by the authors of the device guidelines. These writers are arguably as familiar with the literature and remaining areas of uncertainty as anyone. However, there is a glaring hole in their list. A document that spends so much effort on identifying exactly which patients are the most likely to benefit from a specific therapy must also acknowledge that there needs to be parallel efforts at improving the therapy itself. 

It is not enough to conclude that a patient is at risk of sudden death, for example. Everyone is at risk of sudden death. The real issue is which patients are at a risk that is high enough to warrant exposure to the risks and costs of a specific therapy. Any alterations in the therapy change the risk/benefit equation, and therefore change which patients should be prescribed the therapy. Improvements in therapeutics are as important as improvements in risk stratification. In fact, one could argue that improving our therapies should be the primary long-term goal. 

The above list does include mention of improving the reliability of leads and generators, but fails to promote the development of disruptive technologies that will radically change our ability to tackle the problem of sudden cardiac arrest. A recent example of such disruptive therapy that deserved mention in this document is the totally subcutaneous defibrillator. The word subcutaneous is surprisingly not found anywhere in the updated guidelines. Let’s continue to refine indications for implantable cardiac devices, but let’s work at least as hard at making our devices better.

Reference

1. Epstein AE, DiMarco JP, Ellenbogen KA, et al. 2012 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. Circulation. 2013;127:e283–e352.