Minor, major ECG abnormalities linked to CHD risk
MedWire News: Major and minor electrocardiogram (ECG) abnormalities are associated with an increased risk for coronary heart disease (CHD) events among older adults, say researchers.
"Risk prediction with traditional risk factors is less accurate in older persons compared with middle-aged adults," write Reto Auer (University of California, San Francisco, USA) and colleagues in the Journal of the American Medical Association. "Given the safety, the low cost, and the wide variability of ECG, ECG data might be useful to improve CHD risk prediction in older adults."
They conducted a population-based study of 2192 White and Black adults aged between 70 and 79 years without known cardiovascular disease. The researchers collected information on CHD events including acute myocardial infarction, CHD death, and hospitalization for angina or coronary revascularization over 8 years between 1997 and 1998 and 2006 and 2007.
Baseline and 4-year ECG abnormalities were classified according to the Minnesota Code as major or minor.
At baseline, 276 (13%) participants had minor and 506 (23%) had major ECG abnormalities. 0ver the 4-year follow-up period, 351 participants experienced CHD events, including 96 CHD deaths, 101 acute myocardial infarctions, and 154 hospitalizations for angina or coronary revascularization.
Baseline minor and major ECG abnormalities were associated with an increased risk for CHD after adjustment for traditional risk factors, at 29.3 per 1000 person-years for minor abnormalities and 31.6 per 1000 person-years for major abnormalities, compared with 17.2 per 1000 person-years among those with no abnormalities.
Addition of ECG abnormalities to a model containing traditional risk factors alone showed that 13.6% of intermediate-risk participants (defined by Framingham risk score) with major and minor abnormalities were correctly reclassified (overall net reclassification improvement 7.4%).
After 4 years, 208 participants had new and 416 had persistent abnormalities. New and persistent abnormalities were also associated with an increased risk for subsequent CHD events, compared with those who had no abnormalities, at hazard ratios of 2.01 and 1.66, respectively.
"Whether ECG should be incorporated in routine screening of older adults should be evaluated in randomized controlled trials," conclude the authors.
In a related editorial, Philip Greenland (Northwestern University Medical School, Chicago, Illinois, USA) says: "For the time being, in the absence of clear evidence of benefit and no clear implications for costs, the best advice is not to perform ECGs in asymptomatic patients, regardless of age."
He adds: "However, a careful and detailed cost-effectiveness analysis would be a useful next step in the translation of the cumulative risk information into an evidence-based practice recommendation."
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By Piriya Mahendra