The American College of Cardiology Foundation (ACCF), American Heart Association (AHA) and the Heart Rhythm Society jointly released updated guidelines Sept. 10 for use in treating heart rhythm disorders. Chief among the updates are expanded indications for cardiac resynchronization therapy (CRT), suggesting patients with mild heart failure or NYHA Class II should be considered for CRT based on their electrocardiogram.

“These are patients who had previously been excluded from receiving CRT, but studies have shown they can benefit from this procedure. It can really improve their lives by delaying or avoiding worsening heart failure,” said the writing group’s chair Cynthia M. Tracy, MD, director of electrophysiology at George Washington University Hospital in Washington, D.C.

In the guidelines, which amend the 2008 guidelines on device-based therapy of cardiac rhythm abnormalities, the writing group clarified and provided recommendations about which patients are most likely to benefit from CRT.

“There is growing evidence that patients with the widest, most abnormal looking ECG potentially benefit most compared to patients whose ECG are less abnormal,” said Tracy. In particular, patients with wide left bundle-branch block complexes as seen on their ECG seem to do well with CRT.

“It’s very difficult on a case-by-case basis to assess a patient’s likelihood of success,” said Tracy. “Implanting a device is relatively straightforward, but it’s not completely without potential for complication and there are a lot of management issues that come up. You want to be sure you are doing the right thing by your patient and choosing the right device for the right patient.”

By pulling together and examining the best evidence to date, she said the guidelines can provide physicians with “a clear indication for who is most likely to benefit from device-based therapies.”

In addition, other modifications have been made to help physicians decide which patients with atrial fibrillation might benefit from CRT. Specifically, some patients with weak hearts and irregular, slow heart rhythms can benefit from CRT. The committee also summarized the minimum frequency of in-person and remote monitoring of patients with cardiovascular implantable electronic devices.

The original guidelines for device therapy were issued in 2008 and became the first to combine indications for all cardiac implantable electronic devices. The writing group reviewed these earlier recommendations and, other than the new and modified recommendations for CRT, they remain unchanged and current policy for the ACCF and AHA.  

“The updated guidelines extend and clarify current best practices and will continue to evolve as technology advances,” Tracy added.

The writing group included experts in device therapy, cardiovascular care, internal medicine and cardiovascular surgery, as well as pediatric and adult electrophysiology. The guidelines also were developed in collaboration with the American Association for Thoracic Surgery, Heart Failure Society of America and Society of Thoracic Surgeons. The guidelines were published Sept. 10 in Journal of the American College of Cardiology, Circulation and HeartRhythm Journal.

The ACC said that a related appropriateness use document is currently in development that will help to further interpret the best science and apply it to various clinical scenarios.