Thursday, July 31, 2014

Internal Defibrillator Procedure ~ July 31, 2008

Six years ago today I had an operation at Kaiser-Permanante in San Francisco to implant an internal defibrillator-- or an implantable cardioverter defibrillator (ICD). This was recommended by my cardiologist, Dr. Sheryl Garrett, because of damage to my heart after my heart attack nearly ten years ago.

I was resistant at first, but was persuaded by two other cardiologists when my regular doctor was on maternity leave. My good friends Adam, Justin and Martin came to visit me right after the procedure, and Adam took me home by taxi the next day. Fortunately, it hasn't been used yet, though I am rather curious to know what it would feel like. My defibrillator is about the size of an average cell phone on my chest. The battery should be good for another three or four years. Then I'll need another minor procedure to replace the battery, which will actually be the entire unit. Chances are it will then be smaller and more powerful.

An internal defibrillator is a small, battery powered electrical impulse generator that is implanted in patients who are at risk for sudden cardiac arrest. They provide an electrical shock to the heart during periods of irregular heartbeat, and can save someone’s life. Internal defibrillators sense intrinsic cardiac electric potentials, and then send electrical impulses if the potentials are either too infrequent of absent, due to a problem with the patient’s heart. The electrical pulses stimulate the myocardial contraction, which causes the heart to beat at a normal rhythm.

The process of implanting an internal defibrillator is similar to the implantation of a pacemaker, since both devices contain electrode wires that are passed through a vein to the right chambers of the heart. In most cases, the wires are lodged in the apex of the right ventricle, and the device is kept in the patient as long as they live.

An internal defibrillator works to continuously monitor the heart, and detects overly rapid arrhythmias. They can detect ventricular tachycardia, which are a rapid regular beating of the ventricles and the bottom chambers of the heart. Internal defibrillators can also detect a rapid irregular beating of the ventricle, which is referred to as ventricular fibrillation.

When a patient experiences either of these arrhythmias, the pumping efficiency of the heart is impaired. Fainting and sudden cardiac arrest are usually a result if a patient experiences an arrhythmia, but an internal defibrillator can prevent that from occurring. Patients with coronary heart disease and heart muscle diseases tend to experience arrhythmias; therefore they are the most qualified candidates for an internal defibrillator.

The implantation of an internal defibrillator is much less invasive than is used to be, due to advanced techniques and technology. An internal defibrillator is a tiny computer hooked up to a battery, and then placed inside a tiny titanium case. It weighs only about three ounces, and is about the size of a cassette tape. The device is implanted under the skin below the collarbone, and tiny wires are used to send signals from the heart to the internal device. A programmer is also found on the small device, and it allows a doctor to set it at the correct rhythm for each specific patient.

The internal defibrillator is able to correct irregular and regular heart rhythms, just by sending a timed and calibrated electrical shock directly to the heart. It is similar to a defibrillator used in hospitals when someone’s heart stops, yet it is implanted in the body and ready to be used at any time. It can save the life of a loved one suffering from a heart problem, because a stopped heart needs to be shocked right away. By preventing cardiac arrest, patients with heart problems can live normal lives without having to worry. Patients with internal defibrillators can live normal lives and participate in activities they like, since they don’t have to worry about experiencing cardiac arrest or any other serious heart problems.

(Two years about a week and a half ago, I thought that my defibrillator was about to go off, because I had severe pain in that area of my chest. It turned out instead to be an outbreak of shingles-- nevertheless, not a very pleasant experience. I've been on anti-viral medication for a week, and with luck I should have no permanent residual pain. Evidently some older people do. I learned from a doctor at dinner at my weekend retreat that shingles is the primary cause of suicide in patients over 75. I think I caught mine in time. I was persuaded, however, to continue taking vicodin for pain-- that it's essential to break the cycle of nerve irritation. In addition, there is also a shingles vaccine, which I should get some day, since it is possible to get shingles more than once. My good friend Deb Cornue has had it twice a few years ago, and last year had the vaccine, which should prevent any additional outbreaks.)

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