Mortality Study of the Significance of Extrasystoles in an Insured Population

Abstract

The prognostic significance of extrasystoles was evaluated in 712 insured persons with this finding who were followed for an average period of 18 years. At the end of the study 356 persons were alive and 125 were dead. Two hundred and thirty-one persons had terminated their policies at a prior date by maturity or discontinuance and were not followed further. Although the lack of follow-up to 1968 of this latter group imposes limitations on the results and conclusions of the study, their exclusion resulted in no significant change in the mortality ratio of the remaining group of 481 persons followed to death or the anniversary of their policies in 1968. The observed mortality ratios showed no appreciable increase in a group of 604 individuals who were considered to have a normal life expectancy except for the presence of extrasystoles at the time of evaluation for insurance. Similar normal mortality ratios were observed in subgroups with simple and complex supraventricular and ventricular extrasystoles. There was no appreciable difference in mortality when those under 40 and those 40 years of age and over at the time of discovery of extrasystoles were compared. There was no significant difference in mortality between those who responded to exercise with an increase in the number of extrasystoles and those who had no change or a decrease immediately after exercise. An increase in the number of extrasystoles per minute was associated with an increase in mortality. There was a low incidence of sudden death among those with supraventricular extrasystoles. Ventricular extrasystoles, particularly those of complex types, were associated with a high incidence of death from myocardial infarction, often of a sudden nature, particularly in persons under the age of 56 years. There were too few cases of the individual types of complex ventricular extrasystoles to determine whether this was a characteristic of the group as a whole or of one or more of its constituent types. Ventricular extrasystoles in the presence of other cardiac abnormalities and/or elevation of the blood pressure were associated with an increase in mortality. The mortality experience in such persons was distinctly higher than in those with similar degrees of substandard expected mortality whose abnormalities were not of a cardiovascular nature.