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Device therapy
Damage to the heart muscle can cause changes in the electrical system of the heart and thus how the heart beats. There are three different types of devices that can be used in the treatment of heart failure to correct an abnormal heartbeat.
Pacemakers:
The traditional pacemaker has two parts: lead wires and a pulse generator, which houses a battery and a tiny computer. The lead wires sense the heart's electrical activity, and when the computer determines that the heart rhythm is off, it responds by sending electrical impulses to the heart muscle to correct its rate. Pacemakers are usually used to treat heart rhythms that are too slow. But they can also be used to treat fast rhythms or to increase the heart rate in response to changes in the patient's activity level.
Biventricular pacemakers:
In the normal heart, the heartbeat originates in an area of specialized cells in the wall of the right atrium and spreads through the atria (top chambers of the heart), causing them to squeeze blood into the ventricles (bottom chambers of the heart), which then contract, pumping blood to the rest of the body. In a patient with heart failure, the right and left ventricles often fail to pump together, a condition known as dysynchrony. When this occurs, the heart has less time to fill with blood and is unable to pump enough blood out into the body, which eventually worsens the degree of heart failure. Biventricular pacemakers are devices that use an additional lead wire to sense atrial contractions and send an electrical impulse to the two ventricles so that they contract at the same time. Called cardiac resynchronization, this therapy can improve symptoms of heart failure, reduce hospitalizations, increase a patient's tolerance for exercise tolerance, and lengthen life.
To be eligible for a biventricular pacemaker, patients must be suffering from severe or moderately severe heart failure symptoms even though they are taking medications to treat it. In addition, they must be experiencing delayed electrical activation of the heart, such as "intraventricular conduction delay" or "bundle-branch block." Patients also need to be aware that the implanting procedure is technically challenging and has a 10 percent failure rate.
Internal cardioverter defibrillator (ICD):
Patients with heart failure are at risk for life-threatening arrhythmias, such as ventricular fibrillation. This is particularly true of patients who have an ejection fraction of less than 35 percent, have survived sudden cardiac arrest, or have a history of ventricular tachycardia (a fast ventricular arrhythmia). The ICD senses electrical activity and sends a shock to the heart if it detects a dangerous heart rhythm. A study called "Sudden Cardiac Death in Heart Failure Trial," published in the New England Journal of Medicine, found that implantable cardiac defibrillators reduce the risk of death from sudden cardiac arrest by 23 percent in patients with heart failure.
Patients may be treated with all three devices or just one or two, depending on the patient's individual medical condition. Ask your doctors about the risks and benefits of these devices and the follow-up care you would need if one or more were used to treat your heart failure.
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