Vice President Dick Cheney made a quick hospital visit last summer to have his implanted cardiac device replaced. The fact it was considered routine maintenance says much about these miniaturized electrophysical gadgets, which have saved hundreds of thousands of lives worldwide over the past 25 years or so.

Some media erroneously reported Cheney’s procedure as “heart surgery,” or said his device prevents heart attacks. What the No. 2 man in Washington carries in his upper chest is an implantable cardioverter-defibrillator, or ICD. Replacing the unit, which he first received in 2001, required only a minor incision near his shoulder.

An ICD helps prevent sudden cardiac arrest. A heart attack is damage caused to the organ when it cannot get enough oxygen-rich blood, and usually results from clogged arteries. Sudden cardiac arrest (SCA) is an electrical malfunction. The heart’s lower chambers (the ventricles) jump into a rapid, crazy rhythm — fibrillation — and cannot pump blood adequately.

“We joke about the plumbers and electricians,” says Dr. Edward J. Schloss, director of electrophysiology at Christ Hospital, about the related roles of cardiologists, cardiac surgeons and electrophysiologists. “But the electrical side of things is enormously important.”

When SCA occurs, a person can lose consciousness in seconds and die within 10 minutes. Without immediate intervention, the odds of survival are almost nil — which is why these events are often called “sudden cardiac death.”

A defibrillator can shock the ventricles back into a more normal rhythm. You’ve seen emergency room teams use those paddles to jolt a patient. Portable automated external defibrillators (AEDs) — now a common sight in public places such as airports — can be used in emergencies by anyone, even people with no training.
TECHNOLOGY ON GUARD

But what about the thousands of people who are at risk of sudden cardiac arrest, yet are nowhere near a hospital or an AED when the crisis strikes? Experts say nothing beats having technology on guard in your chest.
 

Today, most ICDs — close to 80 percent — are implanted as a preventative treatment for people who are most at risk of SCA. The record shows that patients with these devices simply die less often.

Even the most advanced medications don’t measure up. “Primarily, all the devices have been compared to drugs, and the devices generally perform 50 percent better than drugs,” says Dr. Mehran Attari, director of electrophysiology at University Hospital. Medications used to treat arrhythmias can sometimes cause other irregular heart rhythms, he adds.

“We can intervene early and keep the patient out of the hospital,” Dr. Schloss says. “If we as physicians can help keep people out of hospitals, it will be tremendous for the healthcare system.”

At Christ Hospital, several hundred of these devices are implanted each year, and not in just old, sick people. A newborn or an otherwise healthy, active teenager can have chronic heart arrhythmias and be at risk, Dr. Schloss notes.
 
Dr. Jefferson Burroughs, an electrophysiologist with Greater Cincinnati Cardiovascular Consultants, practices primarily at Christ and Mercy Fairfield hospitals, and performs about 300 device implants each year. He observes that, ironically, healthcare successes contribute to the demand for more electrophysical devices: people who are better at preventing heart disease, or are surviving it with other advanced medicine, can eventually need assistance and protection for the electrical function of their ticker.

In other words, the plumber may keep you in business, but the electrician has to be on call.

DIAGNOSING THE NEED
 
Along with ICDs, other mechanisms are available in the “electrician’s” toolkit, from the familiar pacemakers, which help speed up slow heartbeats, to more advanced CRTs (cardiac resynchronization therapy), which are specially designed for particular heart rhythm problems, such as those experienced by people with congestive heart failure. This technology “never ceases to amaze me,” Dr. Schloss remarks.

For many people, irregular heart rhythms show up during routine checkups or when they're hospitalized for other conditions. Family history of cardiovascular illness is an important factor. If you're experiencing heart palpitations and dizziness, definitely see a doctor.

Specialists say advanced technology helps assess who should have a protective cardiac device. Specialists usually begin with electrocardiograms and echocardiography (echo ultrasound of the heart), Patients may wear ambulatory monitors that record and report arrhythmias and other physiological data.

Diagnostic imaging, including nuclear medicine scans or angiography and even MRI (magnetic resonance imaging) are becoming “absolutely critical” to these patient evaluations, Dr. Schloss adds.

“In many cases, there is no reversible cause, or at least one we can find,” Dr. Attari notes. A key test is determining the "ejection fraction" — the volume of blood pumped from a filled ventricle with each heartbeat.

“It's still a fine line on who may ultimately need them,” Dr. Burroughs observes about the implantable devices. “We don’t want to implant ones that won’t be used, or leave the [at risk] population unprotected.”

The advanced technology isn't cheap. The retail price for ICDs and similar devices — the amount charged to insurers or patients — can range from $27,000 to $80,000, according to local hospitals. Recent studies suggest, however, that the cardiac devices are ultimately cost-effective, even for patients with mildly impaired heart function, according to Dr. Attari. “We are loosening the criteria — the benefits are so high,” he comments.
YOU BARELY FEEL IT

Dr. John C. Holmes, who was the first cardiologist at St. Elizabeth Medical Center in Northern Kentucky and has practiced medicine for more than 40 years, says he has implanted more cardiac devices made by Medtronic Corp. than any doctor in the country. (St. Jude Medical and Guidant, acquired by Boston Scientific, are other leading manufacturers of ICDs.)

“Originally, only surgeons could implant. Now almost all are put in subcutaneously by electrophysiologists,” Dr. Holmes explains. The procedure is fairly quick and simple. A small incision is made, usually under the left collarbone. Thin insulated wires with electrode tips, called the leads, are threaded through a vein and positioned in the heart. They're then connected to the device, which includes the miniaturized battery and computerized components that gather and transmit data, telling the generator when to send low “pacing” pulses or, if needed, the strong defibrillation charge.

Today, a pacemaker has the diameter of a silver dollar and twice its thickness, Dr. Holmes says. A combination cardioverter-defibrillator and pacemaker is about 2.5 inches in diameter and 3/4 of an inch thick. The devices are so small that they cannot be seen or felt beneath the skin, unless the patient is very thin.

Today’s gadgets are much better shielded from electrical interference. “Here’s the most frequent question that everyone asks — it’s about the microwave,” Dr. Holmes notes. “It used to be you had to stay away from microwaves. Most pacemakers now you could put in the microwave. But we don’t,” he jokes.
 
WHAT ABOUT SAFETY?

Local doctors say more patients are aware of negative publicity about cardiac devices, which began with a major recall by Guidant in 2005. More recently, Medtronic pulled its Sprint Fidelis ICD off the market because of concerns about the failure rate of the unit’s leads.
Local doctors point out that this was not a recall, and many praise Medtronic for being extra cautious. The failure rate for the leads is only about 1 percent over five years, Dr. Schloss points out. He tells patients at risk “there’s dramatically more risk without it. The best drugs we have carry a higher failure rate. People tend to demand perfection.”

Most units last about five to seven years. Dick Cheney’s unit was replaced because the battery was nearing its end. The electrode-tipped leads are a different matter. If, over time, they fracture or lose function, duplicate wires may be inserted, because removing leads from vein can be a delicate, even risky procedure.

Doctors say advanced communications features in the latest cardiac devices make it easier for them and assistants to monitor both the patients and the functionality of their equipment. Not long ago, patients marveled at how these little units could store months' worth of heart data, which could be analyzed during a doctor's office visit. Dr. Burroughs notes that the newest devices use wireless technology for telemetry: reporting patient data from home or other locations. Now the units can do this automatically, and send the information to secure web sites “without any patient action or awareness.”