New AHA/ACC/HRS Guidance on Sudden Cardiac Death Prevention

Megan Brooks

November 21, 2017

DALLAS, TX — The American Heart Association (AHA), American College of Cardiology (ACC), and Heart Rhythm Society (HRS) have released an updated guideline for the management of adults with ventricular arrhythmias (VAs) or at risk for sudden cardiac death (SCD)[1].

"This guideline was way overdue," Dr Sana Al-Khatib (Duke University Medical Center, Durham, NC), who chaired the writing committee, told theheart.org | Medscape Cardiology. "It provides up-to-date evidence-based recommendations on the treatment of ventricular arrhythmias and prevention of sudden cardiac death."

With this guideline, said Al-Khatib, clinicians will "know when to suspect that a patient is at an increased risk of sudden cardiac death and to know how to evaluate such a patient and how to treat him or her."

The 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death was published online October 30, 2017 in Circulation.

The comprehensive guideline replaces the 2006 guideline and supersedes some sections of the ACC/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities—specifically those sections on indications for the implantable cardioverter-defibrillator (ICD)—and it updates the SCD prevention recommendations in the 2011 ACCF/AHA guideline for the diagnosis and treatment of hypertrophic cardiomyopathy, the guideline writers note.

Sudden cardiac arrest and its most common consequence, SCD, are "major public-health problems," accounting for approximately 50% of all cardiovascular deaths, with at least 25% being first symptomatic cardiac event. During the past 20 to 30 years, SCD accounted for roughly 230,000 to 350,000 deaths per year in the US, they point out.

For patients with VAs or at increased risk for SCD, the guideline advises clinicians adopt a "shared decision-making approach" in which treatment decisions are based not only on the best available evidence, but also on the patients' health goals, preferences, and values.

"Patients considering implantation of a new ICD or replacement of an existing ICD for a low battery should be informed of their individual risk of SCD and nonsudden death from HF or noncardiac conditions and the effectiveness, safety, and potential complications of the ICD in light of their health goals, preferences and values," the guideline says.

It also advises that in patients with an ICD and a history of cardiac arrest or sustained VAs in whom removal of the ICD is required (as with infection), the wearable cardioverter-defibrillator (WCD) is reasonable for the prevention of SCD.

In the AHA's first scientific advisory on WCDs issued last spring, the organization said a WCD may serve as a temporary means to prevent SCD in patients who have a transient risk of a life-threatening arrhythmia as well as for individuals with an indication for a permanent defibrillator but for whom an ICD is temporarily contraindicated. The statement was endorsed by the Heart Rhythm Society.

The new guideline also provides detailed recommendations for managing specific diseases and syndromes associated with an increased risk of SCD from VA. One recommendation worth highlighting, said Al-Khatib, is the recommendation on primary-prevention ICDs in patients with nonischemic cardiomyopathy.

It states that in patients with nonischemic cardiomyopathy, HF with NYHA class 2–4 symptoms and left ventricular ejection fraction (LVEF) of 35% or less despite guideline-directed medical therapy, an ICD is recommended if meaningful survival of greater than 1 year is expected. In patients with nonischemic cardiomyopathy, HF with NYHA class 1 symptoms, and an LVEF of 35% or less despite guideline-directed medical therapy, an ICD may be considered if meaningful survival of greater than 1 year is expected, it says.

Knowledge Gaps Remain

Despite numerous advances in risk stratification for SCD and prevention and treatment of SCD and VA, many gaps in knowledge remain, the guideline notes. Among them:

  • Identifying patients who are most likely to benefit from an ICD among all ICD-eligible patients. The role of novel markers (including genetic and imaging markers) and combinations of markers should be studied.

  • Characterizing the role of the ICD in patient subgroups not well-represented in the pivotal ICD trials including patients ≥80 years of age and those with kidney disease, especially patients with end-stage renal disease on dialysis, or multiple comorbidities.

  • Developing methods to identify and treat patients at high individual risk for SCD who are not identified by current ICD eligibility criteria, including those who are within 40 days of an MI.

  • Defining the role of the ICD in patients with hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, cardiac sarcoidosis, and inherited cardiac channelopathies in prospective studies (preferably randomized controlled trials).

  • Determining the best approach to patients due for elective ICD generator replacement due to battery depletion but who may now be at low risk for cardiac arrest, such as if significant LVEF improvement has occurred.

  • Obtaining more data on the efficacy and effectiveness of the subcutaneous ICD compared with transvenous ICDs and on the extent of testing required and its use with other novel technologies, including leadless pacemakers.

Al-Khatib has no relevant financial  relationships. Disclosures for the coauthors are listed in the paper.

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