ECG Shows Massive Rise in Lesions During Chilean Earthquake

September 02, 2011

September 2, 2011 (Paris, France) — Nationwide data show there was more than a doubling of people presenting to the emergency room with subepicardial lesions during the weekend of an earthquake in Chile in February 2010, compared with other time periods. This is the first research to show a massive increase in cardiac events in real time while a tragedy was unfolding, study author Dr Edgardo Escobar (ITMS Telemedicina de Chile, Santiago) told heartwire , pointing out that the national telemedicine clinic in Santiago monitors events 24 hours a day, seven days a week.

Dr Edgardo Escobar

Escobar, who presented his findings in a poster at the European Society of Cardiology (ESC) 2011 Congress earlier this week, said that other work, such as that looking at increases in acute coronary syndrome (ACS) following 9/11 in the US, has recorded big rises in cardiac events after extremely stressful occasions, but these have ordinarily been documented in the days and weeks afterward, rather than as the event was actually occurring.

The number of events seen in Chile was also likely a huge underestimate of the true figure, he says, since most of the events recorded were from outside the direct earthquake zone, close to the southern city of Concepción, because feeds into the telemedicine center from this region were interrupted by the earthquake.

Another interesting observation made by the Chilean team was that those with subepicardial lesions presenting to ERs during the earthquake were predominantly female, with women making up over 70% of patients. This is a reversal of the usual pattern of presentation for such events, which is usually 70% men, he said. Hence, it's possible that while the events could have been ST-elevation MIs (STEMIs), many may also have been stress-induced cardiomyopathies (takotsubo), he notes.

Massive Earthquake Was 8.8 on the Richter Scale

The earthquake that hit Chile on February 27, 2010 was one of the largest ever recorded, reaching 8.8 on the Richter scale. The epicenter was 70 miles from Concepción, Chile's second largest city, which itself is 200 miles southwest of the capital, Santiago. The earthquake did cause damage in Santiago and other areas of Chile.

Escobar said ECGs are received into the telemedicine center in Santiago every 10 minutes, all day long, every day of the year. On average, they receive 1400 to 1500 ECGs from all over Chile in a normal 24-hour period.

"We realized that during the weekend of the earthquake we observed a substantial increase in ECGs, so we compared more than 200 000 ECGs in different periods, the year before and during the year of the earthquake, compared with the weekend of the earthquake," he explained.

The incidence of subepidcardial lesions on any given weekend varied from 0.7% to 2.0% of the tracings received, with an average of 1.35%. During the weekend of the earthquake, however, this more than doubled, to 3.41% of tracings (p<0.05 compared with the average 1.35%).

A third of the patients presenting with such lesions during the earthquake weekend did not report comorbidities, 50% had hypertension, 42% had coronary heart disease, and 8% were diabetic, Escobar said.

The association between stress and ACS has been well documented, he notes, with sympathetic hyperactivity observed during traumatic events with concomitant increases in blood pressure, heart rate, and procoagulant states.

"Earthquakes are fortunately enough not frequent, but people who have already had a coronary event or who are high risk and/or hypertensive should be prepared for incredibly stressful situations, perhaps by having aspirin and beta blockers on hand," he advises.

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