Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: FRIDAY, April 19, 1991 TAG: 9104190063
SECTION: NATIONAL/INTERNATIONAL PAGE: A5 EDITION: METRO
SOURCE: Associated Press
DATELINE: WASHINGTON LENGTH: Medium
Richard Verrier, a professor at Georgetown University Medical Center, said that in experiments on dogs his team was able to isolate and identify a faint electrical pulse in the heart that preceded ventricular fibrillation, a disturbed cardiac rhythm that kills within minutes.
"It's like a signal that tells when a bridge is about to break up," Verrier said.
"We saw that whenever the heart is prone to ventricular fibrillation and sudden death there is always an alternation in the T-wave [a specific electrical pulse in the heart]. It alternates and then the heartbeat goes into a chaotic state."
A report on the research is to be published today in the journal Science.
Verrier said his group discovered the unique cardiac signal by passing electrical sensors into the hearts of anesthetized dogs and then making a computer analysis of the electrical pulses in the heart.
Invariably, he said, the hearts produced a distinctive change in the T-waves just before the fatal attack started.
"One beat is large and one beat is small" in the alternation pattern, Verrier said. "In the normal heart, the T-waves are all even. You could superimpose normal T-waves one on top of the other and they would be almost identical."
A normal heartbeat is established by a regular pattern of faint electrical signals in the heart's nerve system. Those signals direct the heart muscles that contract and relax during the cycle of pumping blood.
During ventricular fibrillation, the rhythm is disrupted and the muscles go into irregular spasms that prevent the pumping of blood. Death follows quickly.
Verrier said the next step was to convert his discovery into a system that could be used in routine medical exams.
by CNB