ICDs Best for Preventing Sudden Cardiac Death

ICDs send signals to reset dangerous erratic heartbeats
nurse checking a woman's heartbeat

Sudden cardiac arrest often occurs without prior symptoms and it results in as many as 325,000 deaths a year in the United States. Only 3 to 10 percent of people who experience sudden cardiac arrest outside a hospital setting survive. Today, advances in technology and treatment give hope to those at risk.

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Using implantable cardioverter defibrillators (ICDs) to prevent a cardiac arrest from ever occurring works better than non-ICD treatment, according to a new study sponsored by the Centers for Medicare and Medicaid Services (CMS).

Correcting erratic heartbeats with a “shock”

ICDs are small, wallet-sized devices implanted under the skin (usually just below the collarbone) and programmed to send a life-saving electrical signal to “shock” a fibrillating (erratically beating) heart back to a normal rhythm.

ICDs detect abnormal and potentially lethal arrhythmias and correct them before they cause loss of consciousness, collapse and death.

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Study shows ICDs saved more lives

The study, which was a literature review, found that the use of ICDs saved more lives than medical (non-ICD) therapies. Researchers reviewed published randomized trials on the subject. The results are intended for use as a clinical guide.

Missing factor

Although comprehensive, the study didn’t include two other randomized, controlled studies that shed light on how programming of the ICDs (which determines how often a signal is sent and the intensity of that signal) impacted patient survival.

As a result, “the analysis fails to account for the major impact of how the ICD is programmed on the magnitude of the improvement in survival and upon morbidity proven in RCTs (randomized, controlled trials),” says staff cardiologist Bruce Wilkoff, MD, Director of Cardiac Pacing and Tachyarrhythmia Devices and Associate Section Head of the Pacing and Electrophysiology Section at Cleveland Clinic’s Heart and Vascular Institute, who did not participate in the study but reviewed the results.

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Study confirms benefits of ICDs

Researchers concluded that there is a “high strength of evidence” that ICDs reduce deaths from sudden cardiac arrest and that there is a 28 percent reduction in death rates for certain patient groups when contrasted with medical (non-ICD) treatment.

All things considered, Dr. Wilkoff says that the study confirms the benefits of preventative ICD treatment. He adds that the results would have been even more positive had the two, more recent randomized, controlled studies been included. “They concluded to expand the indications for ICDs, but this was a very conservative expansion and more could have been suggested,” he says.

Could an ICD help you?

In 2003, the CMS judged ICD therapy effective and appropriate for some patients, granting coverage for ICDs for the prevention of sudden cardiac death. This new study provides evidence that the decision helped save lives.

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