The Wall Street Journal

My father was planning a trip to Europe one summer afternoon when he went to the bathroom and didn't return.

My mother found him dead of a heart attack on the bathroom floor. My husband's grandfather's heart gave out as he was walking down the sidewalk in New York.

Everybody knows somebody who has had a sudden, fatal heart attack, and it's many people's secret fear.

More than 300,000 Americans die of heart disease without making it to the hospital each year; most of them from sudden cardiac arrest, according to the American Heart Association.

In about half of those cases, the heart attack itself is the first symptom.

Deaths from cardiovascular disease in general have dropped dramatically in recent years, but it is still the No. 1 killer of men and women in the US — claiming more lives than cancer, chronic respiratory diseases, accidents and diabetes combined.

That's in part because, for all the advances doctors have made in understanding risk factors, lowering cholesterol with statins and propping open narrowed arteries with stents, most heart attacks are caused when tiny bits of plaque break loose and burst like popcorn kernels, forming clots that block arteries.

That prevents blood from reaching areas of heart muscle, which start to die.

It's hard to predict when that might happen — which is why people who never knew they had heart disease, and people who thought it was under control, still have sudden heart attacks.

"We have terrific therapies that were unimaginable 25 or 30 years ago," says E. Scott Monrad, director of the cardiac catheterisation lab at Montefiore Medical Center in Bronx, N.Y. "But one of the biggest risks is dying before you even get to see a doctor."

Last weekend, scores of commentators on health and political blogs offered theories about what might have been done to save NBC's Tim Russert, who died of a sudden heart attack at work last Friday.

Few details were released, other than that the much-loved "Meet the Press" moderator was being treated for asymptomatic coronary artery disease, had diabetes and an enlarged heart, and had a stress test in April.

Many blog-posters argued that Mr. Russert should have had an angiogram — an invasive diagnostic test in which the coronary arteries are injected with dye and X-rayed to spot blockages.

But even if he had had the procedure an hour before the attack, doctors might not have seen anything to be alarmed about.

More than two-thirds of heart attacks occur in arteries that are less than 50 percent narrowed by plaque buildup — and those are often too small to show up on an angiogram or cause much chest pain.

Similarly, the stress test Mr. Russert had is better suited to detecting significantly narrowed arteries than the small, soft unstable kind of plaque that often causes fatal blood clots.

Indeed, about a third of people who have heart attacks don't have the usual risk factors, such as family history of heart disease, abdominal fat, high blood pressure or high cholesterol.

"Time and again we see examples of unexpected cardiac disease in people who didn't know they had it," says Prediman K. Shah, director of cardiology at Cedars-Sinai Heart Institute in Los Angeles, one of many experts who think wider use of coronary calcium CT scans could help spot more people at risk of soft-plaque blockages.

The noninvasive procedure takes about 15 minutes and costs a few hundred dollars. But few insurers cover it because there is scant evidence that treating people on that basis saves lives.

At a minimum, seeing a picture of the calcium lining their arteries can be a wake-up call for patients to take their coronary-artery disease seriously and to be diligent in taking medication, exercising and making other healthy lifestyle changes.

Mr. Russert's family and physicians haven't disclosed how his coronary artery disease was diagnosed, or how he was being treated.

NBC colleagues said the 58-year-old journalist had been working to control his condition with exercise and diet, though his weight was an ongoing struggle.

He had also returned from a family trip to Italy the day before, following a grueling — but exhilarating — political primary season.

Not all heart attacks are fatal. Most of the 1.2 million Americans who had one last year survived.

If the area of oxygen-starved heart muscle is small, or in the right ventricle, the heart can often keep pumping, allowing the patient to make it to a hospital, where doctors can break up the blockage with a clot-dissolving drug or catheterisation.

The situation becomes rapidly fatal if the heart starts beating wildly, and ineffectively, as it struggles to keep pumping. Unless it is jolted back into a normal rhythm within a few minutes, the patient's brain will starve for oxygen and shut down.

Some patients with enlarged hearts like Mr. Russert's are candidates for internal defibrillators that can continuously monitor heart rhythm and keep it regular automatically.

ice President Dick Cheney, who has survived four heart attacks, has one.

Many airports, shopping malls, schools and offices have portable Automatic External Defibrillators, or AEDs, on hand as well.

They're designed to automatically assess a victim's heart rhythm and administer an electrical jolt as needed.

The NBC office reportedly didn't have an AED, but an intern performed cardiopulmonary resuscitation on Mr. Russert until paramedics arrived with a defibrillator.

"The earlier CPR is started, the higher the rate of success," says Dr. Monrad, who says he has had several cases in which vigorous CPR in the field bought precious time and saved a life. On average, however, only a small percentage of people in full cardiac arrests are successfully revived.

More widespread use of AEDs and wider CPR training could save some future victims' lives. Some bloggers suggested that more-aggressive treatment of Mr. Russert's artery disease might have bought him some time, though most experts declined to speculate.

But stents, angioplasty and bypass surgery are only stop-gap measures that don't do anything to halt the progress of the underlying disease.

"Every time I do a procedure on a patient, the family comes up and says, 'Now we don't have to worry anymore', but that's the wrong message," says Dr. Monrad. "Physicians have to be tough on the standards we set for patients, and patients have to be tougher about the kind of lifestyle choices they make."

The heart has many mysteries that scientists are still unravelling, such as what causes those killer bits of plaque to rupture, the role of inflammation, the complex interplay of diet, vitamins and amino acids like homocysteine.

Even the size of cholesterol particles is under scrutiny. "The more small LDL particles you have, the higher your risk of heart disease," says Larry McCleary, a former paediatric neurosurgeon at Denver Children's Hospital who had a heart attack while on rounds at age 46, and has since lost weight, reduced his blood pressure and triglycerides, and exercises daily.

"It's important that each person take responsibility for taking care of themselves," says Edmund Herrold, a clinical cardiologist in New York City and professor at Weill Cornell Medical College.

"Get a regular checkup. Watch your weight and your blood pressure and your cholesterol and if you have diabetes, keep that under control. Exercise. Take an aspirin every day. Eliminate meat.

There's no guarantee, but you can dramatically lower the risk of a cardiac event if you pay attention to these issues."