Breathlessness, lung function and the risk of heart attack.

Men with moderate or severe breathlessness had a greater than two-fold risk of suffering a major ischaemic heart disease (IHD) event compared to men with no evidence of breathlessness, based on 7.5-year follow-up in a prospective study of 7735 British men aged 40-59 years. Even after adjustment for other risk factors, including cigarette smoking, the relative risk remained two-fold. Men in the lowest fifth of the forced expiratory volume is 1 s (FEV1) distribution also had a two-fold risk of IHD compared to men in the highest fifth after similar adjustment. In part, the role of breathlessness as a risk factor for major IHD events was explained by its strong association with pre-existing, but usually undiagnosed, IHD. However, breathlessness was associated with an increased risk of heart attack even in men without any evidence of pre-existing IHD at screening. FEV1 was related to risk of a major IHD event in men without evidence of pre-existing IHD at screening and in men with previously undiagnosed IHD detected at screening. Measures of breathlessness and lung function could be more widely used in clinical situations and in screening as additional independent indicators of both unrecognized IHD and of risk for major IHD events.