Funnel chest: its effect on cardiac function.

Funnel chest, with its considerable sternal depression and obvious interference with the topography of the heart, has for some time been made the subject of the attractive paradox that, in the vast majority of cases, it has no effect on cardiac function. True, it is conceded that the deformity may in rare instances be responsible for decompensation severe enough to cause congestive failure but there exists the greatest reluctance to attribute to it any less dramatic evidences of interference with the heart's action. The all or nothing rule seems to be invoked. There are, however, recent writers who take what seems to be a more logical stand in suggesting that diminished exercise tolerance is common in cases of funnel chest and that cardiac incompetence is its cause. Such opinions have been expressed by Lester (1950a, b, 1954), Ravitch (1951), Wachtel, Ravitch and Grishman (1956), Chin (1957) and the present author (1955). These statements are made in reporting details of large series of cases personally treated by the authors. The essential feature of the deformity of funnel chest is a depression of the sternum, most marked at the sternoxiphisternal junction. In the funnelchested infant this area retracts markedly on inspiration but the paradoxical movement progressively decreases until at about the age of 4 years it is replaced by orthodox movement of small amplitude. Continued chest development is characterized by the failure of the midline anteroposterior diameter to increase commensurately with the growth of the more lateral parts of the chest, i.e. the funnel becomes deeper. During this period the heart is undergoing the normal increase in size with age, with the result that eventually it may suffer compression between the sternum and the vertebral column. Although at times, this pincer action may be diminished by displacement of the organ to the left, the effect on cardiac function is similar to that of constrictive pericarditis.