Comparative mortality in asymptomatic men issued standard insurance with routine ECG classified as normal or with...

From a prospective electrocardiogram (ECG) study file at the New England Mutual Life Insurance Company, cases were selected on the basis of men issued standard insurance, without symptoms, but with a routine ECG interpreted as normal or with minor low amplitude T wave (+0.5 mm to +1.0 mm). There were 1460 men so classified, with interpretations made between May 1, 1954, and December 31, 1966, and cases followed to July 1, 1970.

In a mean follow-up (FU) of 7.6 years, there were 50 deaths in 12,043 person-years of exposure, with a mean annual mortality rate of 4.4 per 1000 per year, lower than the 4.9 expected from company age/sex/duration-matched rates. However, the annual excess death rate (EDR) of the 12% of men with minor low T waves was +3.1 per 1000 per year, significantly higher than the EDR of -0.9 in the 88% of men with T waves of normal amplitude (+1.0 mm or higher).

When a routine ECG is classified as satisfactory for standard issue (normal or with minor low T wave), the mortality is lower than for all standard issues on male applicants of all ages (mostly without any ECG for review). Nevertheless, in the 12% of men with minor low T wave amplitude as defined for this study, there was significant excess mortality observed, with a mortality ratio (MR) of 188% and an EDR of +4.0 per 1000 per year, when compared with mortality of the men with completely normal T Waves.