Book - Congenital Cardiac Disease 12

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Abbott ME. Congenital Cardiac Disease (1915) Osler & Mccrae's Modern Medicine 6, 2nd Edition.

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1915 Congenital Cardiac: Congenital Cardiac Disease | Heart Development | Literature | Etiology | Cyanosis | Classification | Pericardium | Heart Displacement | Whole Heart | Anomalous Septa | Interauricular Septum | Interventricular Septum | Absence of Cardiac Septa | Aortic Septum | Pulmonary Stenosis and Atresia | Pulmonary Artery Dilatation | Aortic Stenosis or Atresia | Primary Patency and Ductus Arteriosus | Aorta Coarctation | Aorta Hypoplasia | Diagnosis Prognosis and Treatment | Figures | Embryology History | Historic Disclaimer

Primary Patency and Anomalies of the Ductus Arteriosus Botalli

The ductus arteriosus of the fetus is a short, thick trunk, 10 to 15 mm. long, running from the left branch of the pulmonary artery directly after the bifurcation to the under side of the arch of the aorta just beyond the origin of the left subclavian artery, which serves to carry the unaerated blood, returned from the head and upper extremities, to the descending aorta, whence it passes to the placenta. At birth the ductus undergoes a rapid involution, its lumen becomes practically impermeable about the third week of life, the alterations in its wall, which lead to its permanent obliteration, going on for some months, and finally transforming it into the ligamentum arteriosum of later life. The average diameter of the patent ductus at birth is given by Terordt at 5 to 6.8 mm. and by Theremin as 4.8 mm. But when filled with fluid during life, or experimentally injected directly after death, it is found to be much larger. Thus in a series of infant hearts prepared by Klotz, in which he injected the ductus from the aorta with gelatin at autopsy, it was found in the newly born to be fully equal in size to the main pulmonary trunk. He ascribes its apparent smallness as usually seen postmortem to the firm contraction of the muscular wall.

The ductus may (1) remain patent throughout life, (2) undergo aneurismal dilatation, (3) it may be absent, or (4) it may have an anomalous origin or course.



^ Trans. Path. Soc, London, 1903, liv.


Patency of the ductus is not infrequent in combination with other cardiac defects, especially those in which there is some serious interference with the pulmonary circulation. It occurred in 166 of this series of cases, in 21 of which it was combined with pulmonary atresia, in 14 with pulmonary stenosis, and in 23 with transposition of the great trunks. As an isolated condition it is among the more infrequent of cardiac anomalies. The first carefully recorded case of primary patency with autopsy findings, was diagnosed before death and published by Bernutz^ in 1849. Six cases were collected by Almagro^ in 1862, 12 by Gerhardt^ in 1867, 20 by Wrany^ in 1871, and 26 by Vierordt in 1898. Herxheimer enumerated all the above in 38 cases collected in 1910, while Wells,^ in 1908, found 41. A careful anal}' sis of 34 cases with, and 37 without, autopsy report was published by Goodman^ in 1910, and there are important clinical studies by Hochsinger, Gillett, Taylor,^ and Wessler.^ From these and other sources, 64 cases of uncomplicated primary patency with clinical history and autopsy reports, have been analyzed in this series. Of these, 18 are in infants under two years, and 46 in "adults" over this age. As of special interest, or not included by other writers, may be mentioned the cases by Hewitt,^*^ Hall,^^ Kingsley^^ Thompson^^ and Carpenter^* in infants; and Kaulich,^^ Fagge,^^ Darier,^'^ Schrotter,^^ Drasche,^^ Garipuyj^" Crouzet,^^ Greenhow,"^ Gibson,^^ Wells, Schnitzler, and Mead,-^ in adults, as well as 13 adult cases quoted below, in which the patency was complicated by acute infective pulmonary endarteritis.


Pathogenesis

The causes of persistent patency of the duct are to be sought in the conditions of its normal closure, and this must depend upon the influences, mechanical or otherwise, of the changes in the circulation at birth, and upon the consequent alterations in the vessel wall, itself a fetal structure destined to involution. As possible factors in the process of closure may be enumerated: (1) peculiarities in the histological structure of the ductus wall, (2) alterations in the bloodpressure at birth, (3) modifications at birth in the position of the ductus relative to the aorta and pulmonary artery, and other mechanical factors preventing entrance of blood from the aortic side.


1. Histology. - The ductus wall is poor in elastic tissue as compared with the aorta and pulmonary artery, but is relatively rich in muscular elements, which, as well as the elastic tissue are known to undergo marked increase during the later months of intra-uterine life. More particularly a loose, subintimal layer of muscle is present (Thoma^ ; this evidently corresponds to Jore's musculo-elastic layer of the arterial wall, which is here developed both at an earlier period and to a greater extent than in the aorta and pulmonary artery. It is especially marked at either extremity of the duct where it can be seen to pass into and, indeed, to form, the musculo-elastic layer of the aorta (Klotz). When the canal is emptied of contents, as happens after birth, this increased muscularity enables it to contract firmly, so that its walls remain in juxtaposition and may undergo obliterative endarteritis.


1 Arch. -Gen. de Med., 1849, xx, 415. \These de Paris, 1862, p. 67.

^ Jena. Zeitsch. f. Med. u. Naturwis., 1867, Bd. iii. Westr. Jahrb.f. Padiatr., 1871, Bd. i, p. 1.

5 Am. Jour. Med. Sc, 1908, pp. 136, 381.

6 Univ. of Penn. Med. Bull., 1910, xxiii, 509. ^ Gaz. d. hop., 1910, 83, p. 1419. 8 Guy's Hosp. Gaz., May, 1901, p. 197.

^ Am. Jour. Med. Sc, 1913, cxlv, 543. " Trans. Path. Soc. London, ix, 48.

^^Arch. Middlesex Hosp. Clin., Series XIII, 1913, p. 39.

^ Johns Hopkins Hosp. Bidl., 1911, xxii, 239.

13 Edin. Hosp. Reports, 1900, vi, 57.

" Proc. Roy. Soc. Dis. Ch., 1909, ii, part 1, p. 163.

15 Viert. f. prak. Heilk., 1862, ii, 92.

1^ Guy's Hosp. Reports, 1873, xviii, 22.

" Bull, de la Soc. Anat. de Paris, 1885, x, 55.

^^Zeit.f. klin. Med., 1901, xliii, 161.

" Wien. klin. Woch., 1898, xi, p. 1195.

20 Bull, de la Soc. Anat., February, 1907, p. 179.

^1 Ibid., 1869, xiv, 323. 22 QHn. Soc. Trans., 1876, ix, 152.

^^Edin. Med. Journ., 1900, n. s., viii, 1, 212, 436.

^ Jour. Am. Med. Assn., December 24, 1910.



2. Alterations in the Blood pressure at Birth. - Previous to birth, the pressure is highest in the right side of the heart; the pulmonary arteries are small, and almost all the blood passes through the ductus into the aorta. At birth the lungs are expanded, their capillaries are opened, and there is an immediate lowering of pulmonary blood pressure. Dr. Adami suggests that during the first few days of life the aortic tension, and therefore the mean blood pressure in the body as a whole, is also lowered, owing to the reduced amount of work which the heart is called upon to perform, after the cutting off of the placental circulation, and that this reduction in the mean blood pressure is the cause of the collapse of the ductus, and the main factor in closure. Kirstein also believes that a pressure equilibrium is established between the aortic and pulmonary circulations, which prevents a current through the ductus and thus permits of its obliteration, while Klotz thinks that alterations in the pulmonary pressure at birth, and the relative muscularity of the ductus wall are together sufficient to account for closure.

3. Nevertheless, mechanical conditions preventing the flow of blood through the ductus from the side of the aorta have been adduced by many workers, and may reasonably be supposed to assist in the process of closure, especially when the pressure in the aorta comes to exceed that in the pulmonary circulation. Schantz supposed a stretching of the duct by the movement of the pericardium, pulmonary artery, displaced thoracic organs, and sternum, in the initial respiration, and Strassman described, on the basis of a large number of injection experiments, a fold in the aortic wall at the upper border of the mouth of the duct, which appears about the seventh month, and which he thinks closes its opening in a valvular manner when the pressure rises in the aorta at birth. This theory of a valvular aortic fold has been widely accepted and has received recent confirmation in the experimental work of Fromberg.2 Nevertheless, its constancy in infants, and its valvular action when present, has been gravely disputed by such careful observers as Klotz, Kirstein and Stienon.^ The last word on this subject has come from Stienon, who has found that Strassman's fold is not shown on plaster casts of the ductus and adjacent vessels in the newly born, made under low pressure, and ascribes its appearance postmortem to the falling together of the canal after its evacuation. From the study of a large number of such casts of the aortic isthmus and of patent ductus at various ages, he concludes that the essential mechanical factor in closure is the dilatation of the fetal isthmus, which is produced by raised aortic tension after birth, so that the latter has the secondary effect of favoring closure by pressure of the dilated isthmus on the aortic end of the duct. Dislocation of the thoracic organs in the establishment of respiration probably also assists in diverting the circulation.


1 Virchows Archiv, 1883, vol. xciii, 443.

2 Baumgar. Arbeit, aus. d. Geb. d. Path., 1914, ix, 198.

3 Archiv. de Biol., 1912, xxvii, 801.


From the above considerations the general conclusion may be drawn that continued patency will occur (1) in conditions in which the blood pressure, either in the aorta or pulmonary artery, is maintained at a level approximating that before birth (as in atelectasis of the lungs), or in which, for any other cause, a high positive pressure in the ductus is maintained; (2) when a congenital defect in the structure of the ductus wall exists. That such a defect is not uncommonly the cause of patency is suggested by the frequent association of anomalies elsewhere in the body and by the not uncommon occurrence of a history of syphilis, or of anomalies in other members of the same generation, as in De la Camp's remarkable series of six brothers and sisters all with characteristic physical signs of patent duct.


That raised pulmonary pressure is usually at fault is evidenced by the frequent history of atelectasis of the lungs, diflBculty in suckling or prolonged delivery in the mother, seen in the present series. In support of Stienon's view, that dilatation of the fetal isthmus is an important factor, we may note that persistent patency is associated in most adult cases with a certain degree of coarctation of the aorta, and that the process of closure after birth is, like dilatation of the isthmus, a gradual one, extending over the first weeks of life and often not completed until the third month.

Pathology

Three principal types of patency may be distinguished: (1) The duct may be greatly shortened upon itself so that its ends are approximated to each other, and it disappears as a canal, remaining as a simple aperture between the two great trunks. (2) More frequently the ductus persists as a short canal from 0.4 to 2 cm., long (Vierordt), with a lumen varying in size from one just admitting a bristle to one allowing the passage of a "goose-quill," "pencil," or even, as in Luys' case, the "finger." A patent ductus of long standing is usually shorter and broader than that of infancy or later fetal life. In form this canal may be (a) cylindrical, as is usual in infants, and as was seen in the cases by Fagge, Almagro, Gerhardt, and White^ in adults; or (b) funnel-shaped (i. e., conical, as in a funnel without a stem), with its larger end toward the aorta, as in a case by Murray, in which in a woman aged thirty-six years, it formed a truncated cone three-eighths of an inch long, just admitting a quill, and lying with its base to the aorta. Finally (following Gerhardt's classification into four types, of which the above forms 1, 2a and h constitute the first three), the patent duct may exist (3) as a canal which has undergone aneurismal dilatation.

In a patent ductus with otherwise normal conditions, the blood stream will be directed chiefly from the aorta, where the blood pressure is


1 Trans. Path. Soc, London, 1885, xxxvi, 182.


PLATE VI


Microscopic appearances of wall of patent ductus and adjacent aorta and pulmonary artery in a case of patent ductus arteriosus with acute infective pulmonary endarteritis, showing site of initial lesion at pulmonary end of ductus. Drs. Hamilton and Abbott. (Colored drawing by Dr. J. H. Atkinson.) (Haem. and eos. and elastic tissue stains. Low magnification.)

A rectangular block has been cut to include the whole wall of the ductus (D, D') and a portion of the piilmonary artery (P.A.) and aorta {A) adjacent. A, wall of aorta which is quite healthy. P.A., wall of pulmonary artery. D, D', wall of ductus arteriosus in which the elastic tissue is almost destroyed, and which is surmounted by a thrombotic mass {B) . C, pulmonary end of ductus, showing destruction of elastica, and organization of inflammatory products (z. e., seat of initial lesion). E, aortic end of ductus showing zone of recent inflammatory exudate and invasion of tissue between aorta and pulmonary artery by acute inflammation. F, necrosed area below ductus wall. G, recent acute inflammatory process extending from aortic end of ductus into cellular tissue between aorta and pulmonary artery. H, thrombotic mass overlying wall of pulmonary artery and becoming incorporated with it in neighborhood of pulmonary end of ductus higher, into the pulmonary artery. This is evidenced by the funnel-shaped form with its base toward the aorta, which the canal usually assumes in adults, and by the presence of mycotic vegetations on the adjacent wall of the pulmonary artery in all the cases of acute infective endarteritis in the neighborhood of a patent duct. Wagener's 3 cases, in which the membrane at the pulmonary end bulged into the artery, also indicate this direction of the stream. Dilatation of the pulmonary artery, and hypertrophy and dilatation of the right ventricle, are usual results of patency of long standing. Rauchfuss thought them characteristic of all cases, but exceptions occur. The left ventricle may share in the hypertrophy and the aorta be moderately dilated. In Fagge's case, a woman aged forty-two years, the right ventricle was greatly hypertrophied, being equal to the left in thickness; the right auricle was dilated, and the main pulmonary branches, especially the right, were much dilated. The left ventricle is occasionally hypertrophied in excess of the right. In rare instances, as in Walsham's and Drasche's cases, aged respectively forty-seven and twenty-nine years, the heart may not be hypertrophied at all.

Arteriosclerotic patches are not uncommon in the neighborhood of the patent duct in the aorta, and extensive atheroma may occur also in the pulmonary artery. In Hebb's^ case the atheroma and dilatation of this trunk seem to be explained rather by the obliteration of its left branch through the pressure of the thrombosed duct.

Durno and Brown,^ report a case in a man of thirty-three, of widely patent ductus arteriosus, with extensive atheroma both of the walls of the ductus, and of the greatly dilated pulmonary artery. A small saccular aneurism of the pulmonary close to the ductus had ruptured, forming a dissecting aneurism which in turn burst into the pericardium.

Acute Infective Pulmonary Endarteritis

Vegetations of a malignant character are not uncommon within a patent duct, about its aortic orifice, and on the adjacent wall of the pulmonary artery. There are 13 such cases in our series; in all, the pulmonary artery adjacent to the ductus was extensively diseased, and in all but one (Hamilton and Abbott^), the heart valves were also involved in a malignant endocarditis. This last case was of especial interest because of the strict localization of the infective process to the ductus and the pulmonary artery adjacent, which showed clearly that the acute inflammatory process had originated in the immediate neighborhood of the defect, a point confirmed by microscopic examination, in which the organization of the inflammatory products proceeding at the pulmonary end of the ductus was clearly seen (see Plate VI), thus demonstrating this to have been in all probability, the earliest initial seat of a process, which had elsewhere and later assumed a fulminating, highly destructive character.


The patient was a girl of nineteen years, who presented a clinical picture of septicemia for some weeks before death, and the characteristic physical signs of patent ductus, without valvular involvement, or cyanosis. Postmortem a huge thrombotic mass of vegetations lay in the lumen of the dilated pulmonary artery blocking the orifice of a large patent ductus, and extending into the left pulmonary artery (see Fig. 38). The aorta was stenosed at the isthmus but was otherwise healthy and the endocardium of the heart was free from every trace of disease. Embolic abscesses in the lungs, the vegetations in the pulmonary artery, and the blood culture during life contained swarms of pneumococci. Both the patent ductus and pulmonary endarteritis were diagnosed during life.


1 Trans. Path. Soc, London, vol. xliv, 45. - Lancet, 1908, i, 1692.

^ Trans. Assoc. Am. Phys., 1914, vol. xxix (gives full bibliography).




Fig. 38 Diagrammatic drawing showing acute vegetative endarteritis of pulmonary artery in the neighborhood of the patent ductus arteriosus, and consequent infarcts of the lung. A probe is seen passed through the patent ductus. (W. F. Hamilton and M. E. Abbott.)


The wall of the aorta opposite the ductus was the seat of the mycotic vegetations in some cases, indicating that the infection had proceeded with the current through the ductus and had impinged here.


Paradoxical Embolism

In Schmorl's^ case, an embolus passed from a primary thrombus in the left auricle, through a patent ductus arteriosus to the pulmonary artery. In the cases of acute infective pulmonary endarteritis enumerated above, septic infarcts in both systemic and pulmonary circulations, evidently from emboli passing through the patent ductus, were extremely common, occurring even in those cases in which only the tricuspid valve and pulmonary artery were diseased. Hochhaus based a correct diagnosis upon this feature.



Verhandl. d. deutsch. path. Gesellsch., 1909, xiii, 217.


Symptoms and Signs

Clinical evidence of patency of the ductus is to be sought rather in physical signs than in symptoms, for the latter are often obscure. Nevertheless, their very negative character when taken in combination with the distinctly characteristic physical signs, presents, in the majority of cases, adequate grounds for a correct diagnosis, and this can almost always be made. Careful contributions are now numerous, and a symptom complex has been built up which makes this chapter in congenital defects almost as legible to the clinician as that of any form of acquired cardiac disease. On account of the secondary anatomical changes that are usually induced in a patent ductus of long standing, such as shortening and widening of the duct and dilatation of the pulmonary artery, the picture in infants and early childhood, is somewhat diflferent, and much less distinctive than that in later life. This statement applies especially to the physical signs.


The typical appearance is one of anemia, sometimes profound, which has been described as wax-like. Cyanosis is usually absent; when present it is generally slight and transient, appearing only on exertion, and usually develops late, sometimes as a terminal event. Of the 57 cases in which this point is mentioned, cyanosis was entirely absent in 27, of which 19 were in adults and 8 were in children under two years. Cyanosis was noted as slight in 13 cases, in one of which, Bittorf's (aged eleven years), it was constant, in the others transient, appearing only on crying in Simmons' (aged sixteen weeks), and during anginal attacks in Hale White's case (aged fifty-three years). It was moderate in 4 cases only. In that by Carmichael, dying at three, it came on soon after birth, becoming extreme, with clubbing and a polycythemia of 8,100,000. Coarctation of the aorta was associated with the patent duct, and mitral stenosis with great dilatation of the left auricle was present as well, suggesting a rise of pressure in the pulmonary artery and a possible reversal of flow, venous blood from this vessel entering the aorta through the canal.


Dyspnoeic attacks usually accompanied by transient, but marked cyanosis, are relatively common in infants and are so characteristic of these cases that the name La Cyanose Congenitale Paroxystique has been proposed. Loss of consciousness may occur during the attack and the heart may stop beating, or death may supervene. Three typical cases were reported by Hall in infants, all of whom died during the attack, and others by Sanders, Carmichael, Luys, and Bommer.^ In the latter (aged sixteen weeks) the cyanosis was transient, coming on only during the attacks, which came on especially during feeding, and recurred at last so frequently that the child failed for lack of nourishment; during the attacks the breathing stopped suddenly and deep cyanosis developed, lasting two to four minutes; it passed off entirely as the breath returned, in the interval the color being normal. This is very suggestive of an admixture of venous with arterial blood as the cause of temporary cyanosis, the pressure becoming higher in the pulmonary artery and lower in the aorta during the act of suckling.


In older subjects cardiac seizures of various sorts may replace these suffocative dyspnoeic attacks. Paroxysms of extreme tachycardia (pulse 200), with dyspnoea and bloody expectoration, lasting for some hours, and recurring every few months, are described in a man aged thirty-six years, with dyspnoea and palpitation on exertion for years, but no cyanosis (Bommer). Hale White reports repeated angina-like attacks, in one of which death occurred, in a man aged fifty-three years, with a patent duct the size of the anterior tibial artery, but no hypertrophy of the heart or disease of this or of the aorta.


1 Freiburg Thesis, 1900.



Epistaxis, hematemesis, and hemorrhages from other mucous surfaces are not uncommon (Almagro, Carmichael, Darier, Duroziez). Unless death occurs from some intercurrent condition, as malignant endocarditis or endarteritis, the patients usually die with failing compensation, and dyspnoea is a remarkably constant feature. Sudden death occurred in eleven cases in our series; in six during dyspnoeic attacks, in three, those by Reid, Crouzet and Chessman, without apparent cause, in the case by Mead from rupture of the heart and in that by Durno Brown from rupture of the pulmonary aneurism above described.

Physical signs are almost invariably present, and are usually characteristic in older patients. In infants they are practically indistinguishable from those produced by auricular and ventricular septal defects. This is because the patent duct is at first a straight canal, which does not allow of the passage of a large volume of fluid and because in the absence of dilatation of the pulmonary artery there is less sound produced by the impinging of currents in this situation. Among our 64 cases physical signs were absent in only 8 cases. Absence of physical signs in the case of Walsham, quoted by Vierordt in this connection, must be pronounced doubtful, for the specimen came from the dissecting-room with an indefinite note that cyanosis and pericardial murmurs existed. A negative finding in the cases by Luys and Duroziez was also disputed by Almagro.


The distinctive physical signs (which develop as life proceeds), as well as the absence or late appearance of cyanosis, depend, as Gerhardt pointed out, on the fact that a patent duct of long standing usually has a short, wide lumen through which during systole blood flows freely from the aorta into the pulmonary artery, which dilates accordingly and becomes, with the ductus itself, the chief seat of whatever vibration or murmur the abnormal current may produce; the right ventricle behind it usually undergoes hypertrophy and dilatation as well. Gerhardt described as characteristic a visible systolic pulsation in the second left interspace (indicating the forcible closure of the pulmonary valves), an increased area of cardiac dulness, especially to the right, and a narrow zone of dulness 3 to 4 cm. wide (corresponding, he believed, to the dilated pulmonary artery) lying at the base of the heart, along the left sternal border from the third to the second or first rib, and extending a little way over the first piece of the sternum. This "ribbon-shaped" dulness has been noted by many other observers, and has recently been strikingly confirmed in a number of cases in which Gerhardt's dull area, with characteristic murmur or thrill localized over it, has been found by the a--ray to correspond with a pulsating shadow lying above the base of the heart, which was evidently from its size and position the dilated pulmonary artery. In Bittorf's case this shadow was seen, when looked at from the side, to be the size of a walnut and to pulsate a little later than the heart and synchronously with the aorta. In Arnheim's case the a'-rays showed, besides enormous hypertrophy of both sides of the heart, which occupied nearly the whole left thorax, the greatly enlarged shadow of the pulmonary artery placed above the cardiac shadow "like a cap," and numerous tortuous dilated vessels, indicating an extensive collateral circulation and a probable coexisting coarctation of the aorta. In the cases reported by Schrotter, Mead, and Hamilton and Abbott, the .T-ray cap, and Gerhardt's dulness, were found at autopsy to correspond vnth the dilated pulmonary artery.


When cardiac hypertrophy is marked, precordial bulging, diffuse pulsation, and other evidences will be present. An increased area of cardiac dulness, especiallv to the right, while usual, is not invariable, for the left ventricle may b/hypertrophied in excess of the right (Murray's case), or in rare instances there may be no cardiac hypertrophy at all (Drasche's case).


A thrill, usually systolic, but sometimes continuous through the cardiac cycle, is fairly frequent, and was present in 17 of the 64 cases. It may be diffuse over the precordium, but is usually localized to the neighborhood of the second left interspace, in the region described above as Gerhardt's dull area, or at least is of maximum intensity here. Its transmission obliquely upward below the clavicle (along the course of the pulmonary artery) is said to be pathognomonic.


The auscultatory phenomena are the most important and constant. In infants a harsh systolic murmur with more or less of the above localization is the rule, but in adults a loud murmur is nearly always produced, which is characterized by almost all observers as peculiar, and is variously described as harsh, musical, scraping, scratching, humming, churning, rushing, rolling, and only rarely as blowing. Miiller compares it in his case to "rolling thunder," and says that two different listeners likened it independently to the noise made by a train in passing through a tunnel, and Thayer described it in Mead's case as a "machinery murmur." In rhythm several different t>^es may be made out: (1) The murmur is frequently systolic (as in the cases by Murray, Hale White, Simmons, and Bittorf). (2) It may begin with systole, but continue into and through diastole, either as a continuous hum (Chessman's case), or with a systolic rise (Bommer), or with a rhythmic systolic, and diastolic accentuation. Gibson^ describes as pathognomonic a continuous, rushing murmur which "begins distinctly after the first sound, accompanies the latter part of that sound, occupies the first pause, accompanies the second sound (which may be accentuated in the pulmonary area, or doubled), and finally dies away during the long pause." (3) Sometimes, as in Drasche's case, two independent murmurs are heard at the pulmonary area, the loud, peculiar, systolic one, and a low, short, diastolic, indicating a slight regurgitation into the aorta during the pause. (4) More rarely the murmur is diastolic in rhythm, as in Fagge's case, in which a diastolic murmur, musical and of a wavy character, was localized to the pulmonary cartilage. The point of maximum intensity is usually in the second or third left interspace, and it is often heard very loudly in the first left interspace below the clavicle and over the first part of the sternum and in the back to the left of the third and fourth dorsal vertebrae, and in the left suprascapular region. In Franck's case and in one by Gillet, the murmur was only heard posteriorly in this situation, and not in front at all. It is transmitted over the left ventricle, and its systolic element often is audible over the carotids, sometimes more distinctly over the left than over the right (Gerhardt). It may diminish abruptly below the third left costal cartilage. In this series of 64 cases, among the 18 cases in infants, in 8 a systolic, and in 1 a continuous murmur was present. Among the 46 adults, in 19 cases the murmur was systolic, in 9 "double" and in 14 it was the continuous harsh," "rumbling," "rolling," "churning," "humming" murmur usually with systolic accentuation, described by the earliest students of this subject as characteristic, and which Gibson rightly described as pathognomonic.


1 Medical Press and Circular, May 30, 1906. VOL. IV — 27


Franck mentions, as of diagnostic value, an inspiratory accentuation and an expiratory diminution both of the characteristic murmur and of the radial pulse (pulsus paradoxus), which they explain by saying that during respiration the pressure in the thorax is lowered, so that more blood can enter the pulmonary artery then than during expiration, and this will lead to a smaller pulse wave from the aorta, to a larger current through the canal, and a correspondingly louder murmur.


The second pulmonary sound is frequently much accentuated, and this is very important as distinguishing patency of the duct from pulmonary stenosis with somewhat similar localization of murmur or thrill. On the other hand, in some cases it may be weak or even inaudible.


In the cases by Schrotter and Mead paralysis of the left recurrent laryngeal nerve was present, due to pressure upon the nerve by the enlarged patent duct. Schrotter based a correct diagnosis on this feature. The nerve was degenerated on microscopic examination.


The physical signs are very often obscured by those of other lesions, as malignant endocarditis or arteritis, chronic valvular disease, or other cardiac anomalies so commonly associated. The peculiar character of 'the murmur, its more or less prolonged rhythm, its localization, and that of the thrill when present, high up toward the left infraclavicular region, with the results of .r-ray examination, remain, even in these complicated cases, of the first diagnostic value. Patent duct must be diagnosed also from perforation of the aorta and pulmonary artery just above the semilunar valves, whether oif inflammatory or congenital origin. Brocq^ gives a long series of cases of both types.


So-called aneurisms of the ductus Botalli give rise to no physical signs, being of small size and usually occluded by thrombus. They are generally said to be of little clinical significance, but death from rupture of their walls has been reported and embolism from the thrombus within may lead to a fatal result.


1 Rev. de Med., 1886, vi, 786.


So-called Aneurisms of the Ductus Botalli

This term is used in the literature with a rather irregular application to denote a dilatation in whole or in part of a persistently patent duct. That the cases are not aneurisms in the strict sense is inferred by most writers. Rokitansky uses the qualifying word "so-called." Gruner says that arterial dilatation would often be a better word, as there is usually no change in the vessel wall, and he draws attention to the fact that in the usual beanshaped form the constriction at either end makes the ductus appear larger to the eye than it really is. Klotz has suggested that, as in his injection experiments the duct is seen to be much larger at birth when distended with fluid than when contracted at the autopsy, many of these small, so-called aneurisms, measuring less than 1 cm. in their greatest diameter, are really not even a dilatation, but are a simple distension of a patent duct to its full capacity by the coagulum within. Again, a further confusion exists in that the term is applied more widely by some writers than by others. Nevertheless, the cases recorded form a fairly well-defined group, which, from their rarity and from the fact that the duct is usually occluded by thrombus, are chiefly of pathological interest, although their occasional rupture, and also the risk of embolism from the thrombus within, increase their clinical significance. The first cases reported were by Billard, Thore, and other French writers; Rokitansky followed with his monograph in 1852, and Virchow in 1856; full studies of the literature with original cases are to be found in the theses of Westhoff,^ and Gruner.^


In what may be taken as the classical form (which is that described by Rokitansky) the ductus forms a spherical or ovoid tumor larger at the middle than at either end, but smallest toward the pulmonary artery, with which, as well as with the aorta, it communicates, filled with old or recent thrombus,-and varying in size from a "cherry stone" (Billard) to a "hazel nut" (Thore), or even a walnut (Hebb, Binzer). In Hebb's case,^ in a man aged forty years, an aneurism the size of a small walnut, filled with old clot, lay in the position of the duct, communicating with the aorta by an orifice one-eighth of an inch in diameter, and abutting against the obliterated left pulmonary artery and left bronchus. All the cases recorded are in infants excepting that by Hebb.


In Thoma's* patient, aged twenty-six years, the aorta, from the isthmus downward for about 4 cm., was dilated in the form of a spindle, was lined by atheromatous plaques, and on its right wall opposite the left subclavian artery was a saccular aneurism, in the floor of which lay a small hole representing the lumen of the greatly shortened ductus leading into the pulmonary artery, which was here firmly adherent to the aorta. Microscopic examination showed this aneurism not derived from an expansion of the aortic end of the ductus, but to be a bulging of the aortfc wall, which the writer thought was pulled to the right by the action of the contracted ductus. Rokitansky's 5 cases of funnel-shaped patency were explained by Thoma in the same way, and a special form of "traction aneurism of the infantile aorta" was thus established by him. In Wagener's 3 cases, aged respectively thirty-eight, forty-two, and twenty-three years, the duct formed a distinct canal with a small lumen open on the side of the aorta, where the orifice lay in the floor of a hollow in the wall of this vessel, and was sheltered by a distinct fold of aortic intima projecting downward from above while the pulmonary end was closed in by a thin membrane, which bulged into the pulmonary artery. Mycotic aneurism of the patent duct of the dissecting form has been described by Buhl.


1 Gottingen Diss., 1873 (quoted by Gruner and Voss). - Freiburg Diss., 1904.

^ Trans. Path. Soc, London, 1893, xliv, 45. 4 Virchows Archiv, 1890, Bd. 122, p. 535.


Absence of the Ductus

Absence of the ductus may occur, and is usually associated with hypoplasia and shortening, sometimes with atresia, of the pulmonary artery. It is explained as due to a primary failure of development of the sixth left branchial arch (which persists as the ductus), the stenosis of the pulmonary being secondary. In these cases a septal defect is present, through which the aerated blood passes from the right heart to the aorta.

Anomalous Course

Multiple origin is reported by Peacock in a case of pulmonary stenosis, two small trunks arising at the site of the normal ductus and passing, the smaller into the left, the larger (which was cut short) apparently into the right pulmonary artery. In several cases the canal has opened into the left subclavian. In one case, of right aortic arch, the duct entered the descending aorta below the right subclavian and itself gave off the left subclavian artery.





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Abbott ME. Congenital Cardiac Disease (1915) Osler & Mccrae's Modern Medicine 6, 2nd Edition.

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Cite this page: Hill, M.A. (2019, January 21) Embryology Book - Congenital Cardiac Disease 12. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Book_-_Congenital_Cardiac_Disease_12

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