Bailey and Hickam published this classic paper describing seven cases of mitral regurgitation with chordal rupture in 1944. None of these patients presented with active endocarditis. For each case, the authors provided a detailed account of clinical presentation, evolution of the disease, treatment and autopsy findings. Six patients were male. Three of these patients were older than 70 years whereas the remaining four patients were between 48 and 53 years old. In most instances, the absence of concomitant mitral stenosis and the histological evidence of connective tissue changes led the authors to exclude a rheumatic etiology. The histological descriptions were, however, not specific enough to eliminate with certainty the rheumatic etiology in some cases.
Despite these limitations, the manuscript provided detailed description of valvular lesions indicating their degenerative origin, as recognized today, in most patients.
Bailey and Hickam in their autopsy reports noted the following valvular lesions:
"The voluminous mitral cusps ballooned and bulged upward...As seen from the atrial surface, the mitral valve was thickened and irregular, but there was no significant degree of stenosis...the ballooning of the cusp to which the ruptured chordae tendineae were attached was noted...Although the annulus fibrosus measured 9 cm. in circumference, the orifice measured 5.3 centimeters...The unruptured chordae tendineae were thickened and somewhat lengthened.
The following quotation from the case seven is of great interest particularly with respect to the description of subvalvular apparatus which is commonly observed in Barlow's disease:
"When the atrial surface of the mitral valve was inspected, the posterior cusp was found to bulge upward into the atrium. The orifice admitted three fingers...Those [chordae] of the anterior cusp were attached by a meshwork of fibers, not only along the margin of the cusp, but also for 2 cm. toward the annulus fibrosus. None was ruptured. The Chordae tendineae of the posterior cusp were inserted by a similar network of interlacing fibers over the entire undersurface of the cusp. From this network the usual number of thick chordae tendineae extended to the papillary muscles. Three of the chordae tendineae of the posterior cusp were ruptured."
The histological findings were described as follows:
"...The mitral valve was irregularly thickened because of increase in hyaline connective tissue...the ruptured chordae were composed of very dense, hyalinized connective tissue, with areas of calcification and iron deposit...this connective tissue occasionally showed degeneration."
The valvular lesions described by the authors including annular dilatation, leaflet thickening with excess tissue and chordae elongation or rupture are all characteristics of degenerative mitral valve disease. Furthermore the histologic studies did not show any pathognomonic sign of rheumatic valve disease.
It is important to note that in their discussion the authors did not greatly appreciate the significance of their findings and did not really postulate any hypothesis regarding the potential cause of these valvular lesions. In the summary of their article, these authors remarked: "Patients with bacterial endocarditis were excluded from the series. All showed fibrosis and chronic injury of the mitral valve. In two, the lesions were those of rheumatic heart disease; in the reminder, the changes suggested quiescent rheumatic disease, but were not pathognomonic."
Although Bailey and Hickam did not have a clear understanding of the etiology of valvular disease in their seven patients and evoked the potential role of rheumatic fever, their work should be recognized as the first study in which valvular lesions characterizing a degenerative disease were described with detail and precision.