Battery Problems in the Medtronic Marquis

Many people suffer from cardiac, or heart, conditions. The human heart can develop problems which cause the muscle to beat too quickly, too slowly or in irregular rhythms. Current medical technology uses small devices, called implantable cardioverter-defibrillators, for controlling heart rhythms. However, ICD batteries can fail, as demonstrated by some devices offered by Medtronic. The Marquis model line of ICDs was particularly affected by battery issues.

ICD Features

• An ICD is an electronic device implanted within a patient's chest. The small device is about the size of a pager. Doctors attach sensing wire leads to the patient's heart muscle. The leads attach directly to the ICD device. The leads transmit signals to the ICD when the wires sense an irregular heartbeat. The device immediately produces electrical pulses that alter the heartbeat. The heart should beat normally in response to the pulses. The ICD shuts down after the leads transmit normal heartbeat rhythm information.

Battery Malfunction

• After researching consumer battery complaints, Medtronic announced in 2005 that the Marquis model line of ICDs had a possible battery short within assemblies manufactured prior to December 2003. Poor internal ICD design allowed internal wiring to short out the lithium battery's circuitry. As a result, the battery would consume power quickly, significantly reducing the typical battery life of seven years.

Repercussions

• A depleted battery may not show obvious signs of malfunctioning. As a result, a patient may succumb to heart problems if the ICD depletes all of its battery life. Battery depletion can take as long as several hours or even a few days. However, some patients may experience a short-lived skin warmth above the implanted ICD as a malfunction notification. A patient should contact his doctor immediately if any warmth is felt.

Prevention

• Only a small number of Medtronic Marquis ICDs exhibited this battery problem. Medtronic reported that 187 devices out of 87,000 implants confirmed a battery defect. However, concerned patients have monitoring options that can be performed at home. The doctor can provide a specialized hand-held magnet for the patient. The patient holds the magnet over the ICD implant area. A properly functioning ICD will sound a loud tone. A patient with no tone should contact a doctor immediately. In addition, replacing the ICD may be an option if its functioning is questionable. A doctor and patient must come to an agreement over the proper health choice for the patient.

Current Design

• Marquis ICDs manufactured after December 2003 are not affected by the battery short issue. Medtronic altered the internal ICD design that prevented any short circuits from occurring. However, any patients with questions about their particular ICD device should contact their doctor for any device documentation regarding the date of manufacture.