Harvard Heart Letter

Living with an implantable cardioverter-defibrillator

These high-tech devices can save — and change — a person's life.

Implantable cardioverter-defibrillators (ICDs) save many lives. They monitor the heart's rhythm and rate, emitting a low-energy electrical correction when they detect a minor heart rate abnormality. They can also deliver a more significant jolt, likened to a swift kick in the chest, to halt potentially life-threatening rhythm disruptions.

The earliest ICD success stories were in people whose hearts had suddenly stopped beating and were restarted. Later, use of the devices expanded to people who experienced dangerous rhythm abnormalities in the ventricles, the heart's main pumping chambers. Today, most people who have an ICD implanted get it as a preventive measure after a heart attack or to protect against rhythm problems arising from heart failure.

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