Radiokymography in Patent Ductus Arteriosus

Br Heart J: first published as 10.1136/hrt.11.3.257 on 1 July 1949. Downloaded from RADIOKYMOGRAPHY IN PATENT DUCTUS ARTERIOSUS BY K. SHIRLEY SMITH AND FRANKLIN G. WOOD From The London Chest Hospital Received February 9, 1949 The introduction of radiokymography dates METHOD OF INVESTIGATION AND RADIOGRAPHIC from the pioneer work of Gott and Rosenthal TECHNIQUE (1912). The modern multiple slit kymograph was We have made radiokymographs in every patient developed subsequently by Stumpf and his co- in whom a diagnosis of patent ductus arteriosus was workers (1934), while later studies were made by made or entertained. The majority of these later Faber and Kjaergaard (1936) and Bordet and came to operation and in every instance the diagnosis Fischgold (1937). In an earlier paper one of us was confirmed. The kymographs were all taken (Wood, 1939) described the kymographic patterns with the moving grid technique at a focus film that comprise the borders of the normal cardiac distance of four feet. The grid used has a spacing silhouette. of 11 5 mm. between the horizontal slits. At first, In the present study, X-ray kymography has been an exposure time of 3 seconds was used but later applied to the diagnosis of patent ductus arteriosus. the rate of fall of the was increased to give an The during the past decade of the grid development exposure of 1'8 seconds. At this speed satisfactory http://heart.bmj.com/ surgical treatment of the condition has greatly tracings were obtained with a heart beating at the increased the importance of a diagnosis that may be normal rate, and also in patients with tachycardia. difficult. In some cases the characteristic con- Kymographs in the postero-anterior position tinuous murmur is not present and according to were taken and these were supplemented by films statistics quoted by Brown (1939) the pathogno- in the oblique positions, especially the left oblique, monic murmur is absent in more than half of the whenever this appeared desirable. A standard cases. On the other hand Taussig (1947) claims exposure time was maintained so that the tracings that the diagnosis is based on the finding of a con- made were comparable. This applied particularly on September 28, 2021 by guest. Protected copyright. tinuous murmur over the pulmonary area and that where kymographs before and after operation were unless such a murmur is present the diagnosis cannot contrasted. The exposure factors were 65 KVP for be made with certainty. It is when a murmur children and as much as 90 KVP for full size adults, confined to systole is heard at the pulmonary area using 100 milliamperes with a rotating anode tube. that diagnostic difficulties are likely to arise. Dif- In sixteen patients operation for ligature of the ferentiation from pulmonary stenosis may not patent ductus was subsequently undertaken. be easy and the possibility that patency of the ductus may be associated with other anomalies has to be remembered. It is an essential part of the diagnosis X-RAY APPEARANCES to exclude associated defects since when these exist The abnormality most commonly found in ligature of a ductus may abolish an important postero-anterior films of patients with patent compensatory mechanism. As exploratory opera- ductus arteriosus is a prominence of the pulmonary tions are obviously undesirable, no effort must be arc and, in less degree, of the pulmonary conus. spared to determine the correct diagnosis. We The cardiac outline may in other instances be entirely consider that the radiokymographic appearances normal in patients proved at operation to have the which we now present should help to place the same congenital defect. Taussig (1947) has referred diagnosis of patent ductus arteriosus on a secure to the slight prominence of the pulmonary conus in basis. some normal children, and has insisted that the 257 Br Heart J: first published as 10.1136/hrt.11.3.257 on 1 July 1949. Downloaded from 258 SHIRLEY SMITH AND WOOD diagnosis of patent ductus arteriosus should never the left ventricular region a further three waves can be based solely on the contour of the heart. Con- be seen of a similar rhythm which must also be sequently, the diagnosis must depend largely upon auricular in origin and be ascribed to the left auricle the murmurs unless other means are available, or left auricular appendix which curves forward in such as radiokymography. this area at the root of the great vessels. This The kymographic appearances ofthe left border of provides evidence that the left auricle may form part the cardiac silhouette in the normal heart may be of the left border of the cardiac silhouette. It also summarized as follows. In the ventricular area shows that the mixed movements described must be waves of a certain type are seen; these consist of a partly auricular in origin, the other components curved upper limb due to the slow relaxation of the being the super-imposed pulmonary artery waves. ventricle in diastole and a more horizontal lower This zone ofmixed movements must not be confused limb representing the rapid contraction in systole. with the fine vibration waves described below, which Above this is the zone of mixed or confused move- lie in the ductus area between the aortic and the ments described originally by Stumpf (1934). This pulmonary artery levels. lies between the pulmonary artery waves above and those of the left ventricle below. The aorta and KYMOGRAPHIC SIGNS IN PATENT DUCTUS pulmonary artery show characteristic waves which ARTERIOSUS have an almost horizontal upper limb due to lateral In our displacement by the pulse wave and a sloping lower kymographic study of sixteen patients with limb representing the patent ductus arteriosus proved at operation, we subsequent slower elastic have observed four special features of the left border recoil. of the cardiac Light is thrown on the origin of the mixed move- silhouette. They are as follows. ments by the kymograph shown in Fig. 1 which (1) Para-aortic waves. is taken from a man aged, 70, with complete heart (2) Vibration waves. block. There is one large ventricular wave recorded (3) Exaggerated pulmonary artery waves. in the left ventricular area in each segment whereas (4) Exaggerated upper left ventricular waves. at the lower part of the right border during the Of these four signs the first two relate to the lesion corresponding interval of time three distinct waves itself while the last two are consequences of the are seen which can only be ascribed to auricular hemodynamic disorder caused by the defect. The contractions. In the segment immediately above features of each sign are described as follows. http://heart.bmj.com/ on September 28, 2021 by guest. Protected copyright. A B FIG. 1.-Man, aged 70. Complete A-V block. (A) Kymograph. (B) Tracing showing auricular waves (marked by arrow) on left border of heart. Br Heart J: first published as 10.1136/hrt.11.3.257 on 1 July 1949. Downloaded from RADIOKYMOGRAPHY IN PATENT DUCTUS ARTERIOSUS 259 Para-aortic waves. These are wave forms which position. Fig. 5 shows a kymograph taken in the lie parallel to and lateral to the aortic knuckle. left anterior oblique position. The vibration waves They are less dense than the shadow of the aorta, are seen in the magnified section on the border of but are usually well seen when present as in Fig. 2. the ascending part of the arch of the aorta, a position These waves differ from the zig-zag vascular shadows that is surprising in view of the comparative often seen well away from the mediastinum in the remoteness from the ductus region. However, it is lung fields, which show transmitted pulsation from difficult to assign any other interpretation to these the aorta or left ventricle. This sign was present in waves, which have been encountered on several six of our cases. It has been encountered in no occasions in left oblique films. other condition and we have never seen it in any It is suggested that vibration waves constitute a kymograph taken after ligature of the ductus. visual radiological counterpart of the palpable Vibration waves. These occupy a narrow region clinical thrill, and that they are caused by the immediately below the aortic waves and blend vibration of the ductus and the adjacent parts of the farther down with the pulmonary artery waves. aorta and pulmonary artery. In some of our earlier They are shown in Fig. 3 in which (A) shows the kymographs, the zone of fine wave-forms was not whole kymograph and (B) a magnification of the well seen. This was due in part to the inherent encircled zone in (A). The fine fibration waves difficulties of radiography in young children. With of a frequency of approximately 400 a minute are increased experience of the method and the subject seen at the centre of the magnified zone. Careful better results were obtained and we have found the scrutiny is often required to detect these waves, by zone of fine vave forms to be a frequent feature of the naked eye in the kymograph. The reproduction the kymograph in patent ductus arteriosus, being in Fig. 4 shows ill-defined vibration waves, but the present in 12 of our 16 cases. Moreover, in kymo- accompanying drawing made from the film by trac- graphs taken after operative cure of the condition ing the outline ofthe waves from the film, placed over these special wave forms are no longer seen. a horizontal viewing box, illustrates them and their Exaggerated pulmonary artery waves. These are - -~~~~~~~~ http://heart.bmj.com/ on September 28, 2021 by guest.

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