Letter from the Editor in Chief

DOI: 10.19102/icrm.2011.021201

John Day, MD, FHRS, FACC

Editor-in-Chief

This issue of the Journal features a wide variety of clinical experiences that we hope will offer a positive influence on your practice. Within this letter I would like to focus my commentary on the manuscript that is featured within our Device Therapy section, entitled “Maximizing Cardiac Resynchronization Therapy in Patients with Atrial Fibrillation.” In this article, Lo and Obel provide an excellent review and offer clinical pearls of how to maximize cardiac resynchronization therapy in patients with heart failure and atrial fibrillation.

Atrial fibrillation and heart failure have emerged as the new cardiovascular epidemics, and management of these conditions can prove quite challenging. It is often difficult to determine which came first, the chicken or the egg. Or in this case, the atrial fibrillation or the heart failure? Is it the atrial fibrillation or the heart failure (or a combination of both) which is causing the symptoms? We have found over the years that many heart failure symptoms resolve, or at least improve, by maintaining sinus rhythm.

Our work, much like that of others in the field, suggests that atrial fibrillation has a negative impact on the survival of heart failure patients¹. In addition, we have shown that this negative outcome appears to be independent of the heart rate². Thus, just controlling the rapid heart rate associated with atrial fibrillation appears insufficient when heart failure accompanies atrial fibrillation. Our experience indicates that treatment of heart failure is only optimized when sinus rhythm is maintained. As a likely outcome, we have shown that with elimination of atrial fibrillation by catheter ablation, and thus no further need for antiarrhythmic drug therapy, heart failure generally improves³.

I would now like to briefly discuss our approach to the heart failure/atrial fibrillation patient that is being considered for cardiac resynchronization therapy. Unless there is a compelling need for immediate device therapy (such as significant bradyarrhythmia or sustained ventricular arrhythmia) it is quite possible that with maintenance of sinus rhythm, or to a lesser degree adequate rate control of atrial fibrillation, there will be an improvement of the ejection fraction over the next few months. Indeed, atrial fibrillation potentially represents a reversible cause of heart failure. Thus, particularly for the patient with a non-ischemic cardiomyopathy, our approach is to generally restore sinus rhythm and then re-examine the ejection fraction in 3 months.

When restoring sinus rhythm in the heart failure patient, a simple cardioversion is often insufficient in maintaining long-term sinus rhythm. Oftentimes, maintaining sinus rhythm in heart failure patients can be quite challenging to say the least. Heart failure patients typically have more atrial stretch and fibrosis, as well as heterogeneity of conduction and increased sympathetic activation which all makes maintenance of sinus rhythm even more difficult. Hence, antiarrhythmics are often needed.

Unfortunately our antiarrhythmic options are quite limited in heart failure patients, and the toxicities of these drugs can be particularly worrisome for these already compromised patients. When antiarrhythmics are ineffective, which is generally the situation over time, catheter ablation can be potentially curative in the appropriate patient of both the atrial fibrillation and the heart failure. Over the years we have seen many cases of heart failure resolve with restoration of sinus rhythm, thus our approach (again, in the absence of worrisome brady or ventricular arrhythmias) is to first treat the atrial fibrillation and then recheck the ejection fraction 3 months later.

While many patients with heart failure can significantly improve with restoration of sinus rhythm, often times this may not be the case. This is particularly evident in the older patient with multiple comorbidities, the long-standing persistent atrial fibrillation patient, or the patient with ischemic heart disease- which may not have a dramatic improvement in their ejection fraction with sinus rhythm. For these atrial fibrillation/heart failure patients, and others who meet current indications for cardiac resynchronization therapy (CRT), we will proceed with device implantation. There are certainly many other cases where atrial fibrillation may first appear long after device implantation has already occurred.

I would now like to briefly discuss management of the heart failure patient with atrial fibrillation and a CRT device. Even if the heart failure patient already has a CRT device, it is critically important to not ignore the atrial fibrillation. While the patient may report they were unaware of the atrial fibrillation when it is first noticed during routine check up in the device clinic, we have found that a little deeper digging will note that the atrial fibrillation has, to some degree, worsened their heart failure's clinical picture.

In our experience, CRT patients fare better clinically while in sinus rhythm. When sinus rhythm is maintained we can generally achieve a 98% or greater percentage of biventricular pacing. Unfortunately, atrial fibrillation is the main reason that this goal of 98% biventricular pacing is not achieved. As we have recently shown in nearly 37,000 CRT patients, the ability to provide 98% or greater biventricular pacing significantly improves heart failure survival⁴.

In patients where rhythm control is ineffective, or not an option, it is critical to control the heart rate associated with atrial fibrillation. With maximization of beta-blocker therapy, or even the addition of digoxin to beta-blockade, effective heart rate control can generally be achieved with a very high percentage of biventricular pacing. Additionally, we will generally employ the various specific device algorithms for each company to maximize biventricular pacing in these patients. For those patients with ongoing rapid ventricular rates despite medical therapy we often consider AV node ablation. AV nodal ablation can be very helpful in the CRT patient with symptomatic atrial fibrillation which has not responded to other therapies.

I hope the experiences and techniques shared within this letter are of additional benefit as they accompany Lo and Obel's manuscript from the Device Therapy section in this issue. Please also be sure to check out our Device Therapy Section Editor's follow up commentary as well. This issue of the Journal is packed full of interesting content that we hope will be useful in your daily practice. Our continued efforts in sharing innovative techniques, along with the experiences from difficult to manage conditions, will surely assist in improving patient care and help lead the way for more advanced treatment options. We have truly appreciated your engagement throughout 2011 and are very excited to continue this collaboration into the New Year!

Editor-in-Chief

John Day, MD, FHRS, FACC
Editor-in-Chief
The Journal of Innovations in Cardiac Rhythm Management
JDay@InnovationsCRM.com
Director of Heart Rhythm Services
Intermountain Medical Center
Salt Lake City, UT

References

Bunch TJ, Day JD, Olshansky B, Stolen KQ, Mullin CM. Newly detected atrial fibrillation in patients with an implantable cardioverter defibrillator is a strong risk marker of increased mortality. Heart Rhythm 2009; 6(1):2–8. [CrossRef] [PubMed]
Bunch TJ, Day JD, Olshansky B, Stolen KQ, Mullin C. Atrial fibrillation increases risk across the mean heart rate spectrum in an ICD population. Heart Rhythm 2009: S13–1.
Bunch TJ, May HT, Bair TL, Crandall BG, Weiss JP, Osborn JS, Anderson JL, Muhlestain JB, Horne BD, Lappe DL, Day JD. Systolic heart failure treated with atrial fibrillation ablation have long-term risks of dementia, death, and stroke similar to heart failure patients without atrial fibrillation. Heart Rhythm Journal 2011;8:S377.
Hayes DL, Boehmer JP, Day JD, Gilliam FR3rd, Heidenreich PA, Seth M, Jones PW, Saxon LA. Cardiac resynchronization therapy and the relationship of percent biventricular pacing to symptoms and survival. Heart Rhythm 2011 Sep;8(9):1469–75. Epub 2011 Apr 15. [CrossRef] [PubMed]