Electrocardiographic Minnesota code findings predicting short-term mortality in asymptomatic subjects. The Italian RIFLE Pooling Project (Risk Factors and Life Expectancy).
Aim of the study was to analyze the predictive power on short term mortality of electrocardiographic findings in asymptomatic subjects belonging to samples of the general population. In the Italian RIFLE Pooling Project (Risk Factors and Life Expectancy) 12 180 men and 10 373 women aged 30 to 69 years had a resting electrocardiogram (ECG) recorded at baseline examination. All of them were free from clinically symptomatic heart disease and represented 23 cohorts spread all over Italy. ECGs were read by the Minnesota Code using 5 large categories of abnormalities, i.e. Q-QS abnormalities, ST-T abnormalities, high R. waves, major arrhythmias, and blocks. Some clinically relevant ECG combination of abnormalities were also analyzed. Six-year mortality from coronary heart disease (CHD), cardiovascular diseases (CVD) and all-cause mortality (ALL) were the end-point. Those ECG findings were relatively common and covered the majority (80 to 90%) of all abnormalities found in the general population before excluding subjects with symptomatic heart disease. Most ECG findings on most occasions were associated with an excess mortality from the three end-points in both men and women and among relatively young (age 30-49) and mature (age 50-69) adults. The strongest predictor of fatal events were Q-QS items and blocks. The most consistent predictors were ST-T findings, although this was true for men and not for women. Relative risk against the absence of abnormalities (one by one and all together) were adjusted by multivariate analysis feeding in the models some possible confounders, i.e. age, systolic blood pressure, serum cholesterol, cigarette consumption and body mass index. Relative risks in cells with more than 20 events (cells being separately made by men, women, the 5 ECG findings categories and the 3 end-points) were ranging 1.00 to 9.88 for Q-QS abnormalities, 1.03 to 3.76 for ST-T abnormalities, 1.28 to 5.14 for high R waves, 0.81 to 2.28 for arrhythmias and 0.79 to 3.59 for blocks. Most of these relative risks were statistically significant. Combinations of clinically relevant ECG findings in the same individual (LVH, possible and definite myocardial infarction) were rare but carried a severe prognosis with high and statistically significant relative risks among men (ranging between 3.19 and 7.24) while they could not be properly tested in most cells for women due to the small numbers involved. It is concluded that in the general population high rates of prevalent ignored ECG abnormalities in asymptomatic subjects are associated with significant excess mortality from CHD, CVD and all-cause mortality, suggesting a high prevalence of silent heart disease.
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Istituto Italiano di Medicina Sociale, Roma.
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D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000401:mortality; D003327:Coronary Disease / Q000401:mortality; D004562:Electrocardiography; D005260:Female; D006331:Heart Diseases / Q000175:diagnosis / Q000401:mortality*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008017:Life Expectancy; D008297:Male; D008875:Middle Aged; D009026:Mortality; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D012307:Risk Factors; D012737:Sex Factors