Heart Therapy with Fewer Shocks

By George Leposky

Sudden cardiac arrest kills about 450,000 people a year in the United States, and 95 percent of these deaths are due to ventricular fibrillation – a rapid, fluttering heartbeat that interrupts the heart’s normal blood-pumping rhythm.

For patients with known heart disease that could lead to ventricular fibrillation, an electronic device called a cardiac defibrillator can be implanted in the chest to detect the condition and deliver an electric shock that restores normal beating rhythm.

Despite the availability of implantable cardiac defibrillators (ICDs), however, only about a third of patients who might benefit from the device actually receive it. One reason it hasn’t been more widely used is patients’ fear of receiving painful electric shocks to the heart.

Pain Can Be Avoided

Such pain can be avoided, according to results of a study presented at a recent meeting of the North American Society of Pacing and Electrophysiology (NASPE), the largest U.S. gathering of physicians specializing in heart rhythm disorders.

The large, multicenter, randomized study – called the PainFREE Rx – shows that implantable defibrillators can be programmed effectively and safely to detect rapid heartbeat and deliver painless pacing therapy to normalize heart rhythms, while reducing the number of shocked episodes by more than two-thirds.

According to the study, patients who received pacing as the initial therapy received 70 percent fewer shocks than patients in a control group with traditional ICD programming. This means that, for most patients, ICDs can be programmed so that shocks are reserved for extremely rapid heart rhythms of more than 250 beats per minute.

Different Programming

Standard ICDs are typically programmed to deliver a shock when detecting an abnormally fast heartbeat; state-of-the-art defibrillators can be programmed to distinguish between arrhythmias that can be managed painlessly and those that require shocks. In the study, Medtronic ICDs were used.

PainFREE Rx is the first large clinical trial to compare the use of pacing therapy versus full shocks to treat rapid heartbeats. Preliminary data based on 637 patients showed a 70 percent relative reduction in shocks with pacing as the initial therapy.

The new programming method did not increase the risk of syncope (fainting), death, or accelerating rhythms, or increase the time necessary to normalize the heartbeat.

George Leposky is editor of Ampersand Communications, a news-features syndicate based in Miami, Florida.

© Ampersand Communications

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