ECG anomalies Risk markers for heart attacks

Detect impending heart attacks using long-term ECG

30/09/2011

Heart attack patients are relatively likely to suffer a second in the coming years after their first heart attack. Using computer-aided analysis of electrocardiogram data from more than 4,500 heart attack patients, US researchers led by Zeeshan Syed of the University of Michigan at Ann Arbor have now identified three risk markers, which are abnormalities in long-term ECG and indicate an early onset of heart attack.

Hidden ECG anomalies in heart attack patients
As the US scientists in the journal „Science Translational Medicine“ Reported ECG abnormalities in heart attack patients indicate an imminent second potentially fatal infarct very early on. In analyzing the ECG data from 4,557 heart attack patients who were routinely monitored in the hospital with a 24-hour ECG, US researchers used the methods of so-called data mining and artificial intelligence (AI) to study the extreme to process large amounts of data in a meaningful way and to recognize possible patterns. They found that there are three markers for the risk of further heart attacks, which can, however, be registered during the normal evaluation of the ECG data. The risk markers are on the 24-hour ECG neither audible nor recognizable on the expression, especially since most doctors consider anyway only a section of the ECG, said the US scientists in the journal „Science Translational Medicine“.

Three risk markers for further heart attacks
The three risk markers that were detected in the long-term ECG in the run-up to an impending fatal myocardial infarction are, according to the US researchers, firstly tiny variations over long periods at the normal heart rate, secondly, certain changes in heart rate, which are expressed determine whether the patient's heart reacts normally to the nerve signals, and thirdly, that deviations in the long-term ECG from those of other patients with comparable medical history. These risk markers are barely recognizable by conventional examination methods and would therefore not be perceived as alarm signals, said US scientists at the University of Michigan. As the research leader Zeeshan Syed added, can „Today's methods for the identification of Infarktopfernfern that need the most aggressive therapy, although some groups of patients with a high risk of complications detect“, but the error rate is clearly too high. So would the previous screening methods „up to 70 percent“ miss the deaths, Syed explained. Most of the heart attack patients who used a defibrillator to prevent a sudden cardiac arrest were never needed and most of the patients who died of another heart attack were unable to recognize this risk with previous procedures , said the US scientists.

New findings allow better preventive treatment
Even the detected anomalies would normally hide in a kind of background noise and could therefore only be detected with the aid of the extremely cumbersome computer-assisted analysis, according to the experts. However, the retrospective analysis of ECG data from more than 4,500 heart attack patients has shown that patients who had at least one of the three risk markers, a two- to threefold risk, to a sudden cardiac arrest within the next twelve months after the ECG die. Heart attack patients who had all the markers were even more than 50 percent more at risk of a fatal second heart attack, stressed the US scientists. This corresponds „Thousands or tens of thousands of patients for whom physicians could potentially prescribe effective preventative treatment based on the more individualized assessment of their complication risk”, Zeeshan Syed emphasized the importance of the current research results. (Fp)

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Image: Michael Bührke