New Focused Update for Device Use in Rhythm Disorders

December 28, 2012

The American College of Cardiology Foundation (ACCF), American Heart Association (AHA), and Heart Rhythm Society (HRS) have updated the clinical guidelines for device-based therapy for cardiac rhythm abnormalities and proposed several changes for the use of cardiac resynchronization therapy (CRT) [1].

Chaired by Dr Cynthia Tracy (George Washington University Medical Center, Washington, DC), the 2012 ACCF/AHA/HRS guidelines is an update to the 2008 clinical guidelines for device-based therapy for rhythm disorders, previously reported by heartwire . The 2012 update followed a review of late-breaking clinical trials and published data that were believed to have an impact on patient care.

The new update, published in the Journal of the American College of Cardiology and Circulation, includes sections on the selection of pacemakers and implantable cardioverter defibrillators (ICDs), optimization of technology, cost, and follow-up of implanted devices. "Although the section on follow-up is relatively brief, its importance cannot be overemphasized," note the writing committee. "First, optimal results from an implanted device can be obtained only if the device is adjusted to changing clinical conditions; second, recent advisories and recalls serve as warnings that devices are not infallible, and failure of electronics, batteries, and leads can occur."

Regarding the section on ICDs, the writing committee updated the guidelines to reflect developments in the field and published data related to the efficacy of ICDs in the treatment and prevention of sudden cardiac death and malignant ventricular arrhythmias.

The writing committee also proposed several changes to the recommendations for CRT. The most significant change involves the limitation of a class I indication to patients with a QRS duration ≥150 ms based on the results of multiple analyses of CRT benefit. CRT is also a class I indication for patients with a left bundle bunch block (LBBB) pattern and those with New York Heart Association (NYHA) class II heart failure (and LBBB with QRS duration ≥150 ms). A class IIb indication has been added to CRT for patients with an LVEF ≤30%, ischemic heart failure, sinus rhythm, LBBB, and QRS ≥150 ms, and NYHA class I symptoms.

In the document, the writing committee points out that there is still a need to improve the process of identifying which patients might benefit the most from CRT. In the update, the group does not include a section on the extraction of failed or unused leads because there is not enough evidence to support specific criteria for timing and methods of lead extraction. Instead, they refer physicians to the HRS policy statement on lead extraction.