STUDY LINKS STRESS, CARDIAC DEATHS\'94 quake statistics back hard-to-prove theory.

Byline: Steven J. Gorman Daily News Staff Writer

The 1994 Northridge Earthquake provides compelling evidence to document what has long been presumed by doctors - that fear alone can trigger cardiac arrest, according to a study appearing in today's New England Journal of Medicine.

The analysis of Los Angeles County coroner's records by researchers from Good Samaritan Hospital found that three times as many people as usual died of heart attacks or related coronary illness on the day of the earthquake.

And the number of people who suffered "sudden cardiac deaths" - those who collapsed and died from cardiac arrest virtually on the spot - was five times higher than usual, the study showed.

That number jumped from a daily average of about five on a normal day to 24 on the day of the quake, then fell to fewer than three a day in the week following the quake.

The findings suggest "there was a population of patients who were perhaps destined to die but died earlier because the stress of the earthquake triggered their coronary," said the author of the study, Dr. Robert A. Kloner.

Still, an extrapolation of the data shows that 41 percent of all sudden cardiac deaths, which claim 300,000 American lives a year, may be brought on by emotional stress or some other outside trigger, Kloner said.

Kloner, a cardiologist who is director of research for the Heart Institute at Good Samaritan in downtown Los Angeles, said he undertook the study after noticing that his own heart rate spiked during the Jan. 17, 1994 temblor and its aftershocks.

"In earthquake-prone areas, hospitals and EMT facilities should know about this and at least have some contingency plans," he said Wednesday.

A related study by Kloner to appear in the American Journal of Cardiology in April found that the number of heart attacks reported by 72 coronary care units countywide jumped 35 percent the day of the quake, Kloner said.

Overall, 51 people died the day of the Northridge Quake from atherosclerotic heart disease, a condition in which the walls of the arteries leading to the heart become thickened with a buildup of fat and fibrous tissue, the study published today said.

That is a significant jump from the daily average of 16 deaths from coronary artery disease recorded the week before the earthquake, the study said.

The difference suggests that 35 coronary heart-disease deaths were triggered by emotional stress from the quake, about a dozen more than previously attributed to the temblor by the Coroner's Office.

By comparison, 35 people in Los Angeles County were killed by collapsing structures, electrocution, car wrecks and other accidents associated with the quake, said Craig Harvey, chief of operations for the county Coroner's Office.

Of all the fatal coronaries the study counted for the day of the quake, 24 were characterized as sudden cardiac deaths - 19 more than the daily average the week before but about the same number of quake-related cardiac deaths tallied by the coroner.

Only three of the victims were engaged in unusual physical exertion when they collapsed, the study found.

"Our interpretation of that is that emotional stress must be very important," Kloner said.

Stress in people with underlying coronary disease can trigger fatal disruptions of blood flow in several ways - by causing erratic quivering of the heart, setting off spasms of the arteries or breaking off a lump of fatty buildup in the artery to form a clot, he said.

Kloner said causal link between emotional stress and cardiac deaths has long been suspected but is difficult to document.

"This was really a chance to look at what happens when a large, densely populated area suddenly experiences a horrible stress," he said.

The larger implication of the study, he said, is the importance of reducing stress among people with heart disease or who are at high risk for heart disease, including those who smoke, or are overweight, have high blood pressure or high cholesterol.

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Dr. Robert Kloner, a researcher at Good Samaritan Hospital in Los Angeles, authored the report on the effect of fear on coronary deaths. Evan Yee/Daily News