P1 Ri (* 1 I'CI ( ;N%,%('1' ANO ('ONGIfNil ' :1L HLAk'I I715F`ASi' .
lack of specificity with the diversified )" plciotropic') characier of cantenlial heart diseases, even those hat seem to be Mendelian . 'Iogetiler they have given rise to the notions that ,hat is inherited is not unr~p4++fogir but uu+rppugeu'tir . The geneticist should he looking for unifying defects of develop . mental mechtmisms . not unity in their effects . ']'he risks of recurrence may be compared with the 5117r for dominant genes and 257 for recessive genes . The in . crease in risk for non-Mendelian traits is then small . One would have expected as much, fur a high recurrence risk (such as occurs in the simple Mendelixing cases) takes a heavy selective loll, so that the traits should remain rare . (To the clinician . congenital heart disease may appear to he rare . but among genetic diseases it is astonishingly common) . Massive empiric evidence confirms the predicted low recurrence risk- The average recurrence risk in congenital heart disease is usually not = J7r to 597 . the kind of risk figure one uses in counseling when all else fails . Needless to say . wherever an adequate history would furnish a more rational basis for calculating risk (lot' instance for the Jcrvell-LangeNielsen syndrome which is autosomal recessive). one would use that risk. Semispecific family recurrence risk . Between the extreme rigorof the Mendelian analysis and the nihilism of pure black box risk, there is a type of analysis that is growing in popularity. It is based on the notion [hat certain groups of lesions may occur together more often [ban others because they are more closely related in etiology and pathogenesis . such as hemodynamics or contributions from the neural crest . The classification of congenital heart disease by Clark (7) is an attempt at such a rational ordering . One instance for which there is now excellent evidence is defects of the left
tArc V.,) Is. No .2 Augurs -1111-42
ventricular outflow tract . Too narrow a concern with anatomic specificity would obscure this valuable c lue . a s would too indiscriminate a pooling of data. The relation can be usefully if tentatively interpreted as the result of common hydraulic factors at work . Conclusion Most of our useful common knowledge about the genetics
of congenital pearl disease appeals to a few rational principies, which may be somewhat refined by better phenotyping, linkage analysis and exploration of candidate genes . All the current indications are that the major advances in this field in the next 10 years will come from a deeper understanding of pathogenesis and the accurate measurement of the effects of morphogenetic genes.
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Filggins ITT. The epidemialogy of . ..genital heap disease . I Ch- Dv PMS .ig :6Y9-7'_t . 3. MuKuxck VA . hlendelirn Inheritance in hl:n. 9th ed . Baltimore. John, Hopkins Cnirersity Press . 1990. a. %I-,,-h, EA. Chore GA . Principle, 4G,-,v Counseling . Chicago: Year uses Medical . 1975. 5. Nar JJ . Nura AS . Gencuc epidemiolugy pf congenital heart disease . In: '.
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Pregnancy and Congenital Heart Disease JOSEPH K . PERLOFF . MD. FACC
The overall prevalence of pregnancies complicated by cardiac disease has decreasr'd somewhat during the last several decades in North America and Western Europe . but the principal change has been less a difference in prevalence than a change in the relative incidence of the various types of cardiac disorders in pregnant women (I) . Congenital heart disease is encountered more often . whereas the frequency of rheumatic heart disease has declined 1'_I . Survival into adulthood of women with congenital malformations of the heart and circulation results from natural selection or from the benefits of operation . Reparative surgery not only increases the life spun of women with anomalies that have inherent tendencies for
long survival, but also permits an increasing number of women with disorders that were previously fatal in early life to reach reproductive age (3). Central to this topic is the intricate interplay between maternal circulatory and respiratory physiology and maternal congenital heart disease . and the cfl'ccis of this interplay on the fetus that is exposed both to immediate risks that threaten its viability and to reroute risks than express themselves as developmental defects or iransntiued congenital anomalies (3) . An understanding of the relation Setween heart disease and pregnancy presupposes knowledge of the maternal circulatory and respiratory adaptations to the normal gravid state.
IACC Val. Ix . Nu. 2 Augu,a nWr311-it Table 1 . Common Malformations With Expected Adult Survival Aeyawtie Axial t,ptal detect txccundaml Pmont ducts, ararimu, Pulmanap' valve "en-, Coarcoauon of the aorta Annie valve dismne Cyan.
Trrralogy of fallul Listed,a dewenJmg order of PI-k- am0ag ,amen.
Common congenital malformations of the heart and cir . culation in which anoperuud utrntrab c oron •a/ into childhearing age can be anticipated are listed m Table I in approximate order of prevalence among women . Three uncommon congenital cardiac diseases ate relevant because of the probability of presence in reproductive age •--namely . primary pulmonary hypenension . Ebstctr ; s anornaly elf the tricuspid valve and congenital complete hewn block f31 . The postoperative woman with cardiac disease . This now constitutes one of the most important categories of pregnancy and heart disease and repres:nts a growing patient population (31. Successful cardiac surgery improves fertility and stabilizes the pregnancy in women whose heart disease had reduced their sexual and ovarian functions . Accordingly, women who had been physiologically ill equipped to bear children or who previously would net in all probability have reached reproductive age are now presenting for cusletric and cardiologic care after reparative surgery for congenital heart disease (4) . Pregnancy affects maternal congenital hear[ disease . :md congenital heart disease affects the gravid female and her fetus . Even though the expectant mother's Cardiac reserve may be encroached on by the hemodynanltc border, of pregnancy, this eneeoachrnent can almost always he sire . cessfully euuntered by addressing factors that aggravate maternal heart disease and reduce circulatory reserve . namely ; 1) anxiety . 2) sodium and water retention . 31 sudden. strenuous or isometric exercise . 41 heat ant' numiditb . 5) anemia . ft) infections_ 7i disturbances in cardiac rhsthm and conduction . and 8) thromboembolic pnodispoailions (1). Maternal mortality generally varies with New York Ileart Association functional class. but in the presence of certain congenital cardiac malformations, childbearing imposes such an awesome threat to maternal survival that pregnancy is proscribed or should be interrupted irrespective of functional class . Pulmonary vascular disease is perhaps the most fo ;midable maternal ri,k epitomized by primary pulmonary hypertension. Eisvrmenger's complex combines the maternal risk of pulmonary vascular disease with the fetal risk of cyanosis . Pulmonary edema . a second major maternal r isk. i s less common in patients with congenital heart disease than in those with acquired heart disease . but the functional adequacy of the ventricle that Serves the systems . circulation-before or after operation-is central to this concern .
PERLAFF AND CONGENITAL HEART DISEASE
Medical management of the gravida with congenital hear) disease. Management of the pregnant patient extends into labor . delivery and the puerperium . A strong consensus (1) favors spontaneous vaginal delivery, with cesarean section reserved for ohsetrlc indications (cephalopelvic disproporuonl or preterni labor in a patient rCM,lvlng anticoagulant therapy with warfarin . Labor in the lateral decubitus position attenuates the hemodynamie fluctuations associated with major uterine contractions in the supine position . Analgesia should be used for relief of pain and apprehension ; the safely of anesthesia is based on the anticipated hemodynams response to a given anesthetic agent . Blood loss should he minimized, especially in patients with pulmonary vascular disease, tetralogy of Faller or nstium secnndom atrial septa) defect . The risk of peripartat phlebothrombesis and paradoxic embolization can be reduced by meticulous leg care . clastic support hose and early ambulation . Prophy laxis for infective endocarditis is important in the medical management of susceptible patients. Cardiovascular drugs in the gravida with congenital heart disease fall principally into too categories : antiarrhythmic agents and anticoagulant agents . The use and efficacy of annarrhythmic agents are similar in principle to their use and efficacy in the nongravid state except for potential placental transfer of the pharmacologic agent and !he increased dose required to treat the mother . Risks to the fetus . Immediate risks to the fetus are determined chiefly by the degree of maternal functional -eserve, n alernal cyanosis and maternal anttcoagtiiation . Cardiac surgery is seldom employed during pregnancy in patients with congenital heart disease . largely obviating the concern that extracorporeal circulation is associated with a high incidence of fetal wastage Anticoagulants during pregnancy confront the fetus with risks that cannot he satisfaeforily resolved . There is no consensus regarding the best method fur administering anticoagulants to pregnant women . Remote feltsl risks take the form of genetic parental trans• mission . teratogenic effects of certain eerdiac drugs (warfarm . for example) and the harmful effects of certain environmental toxins and exposures. Feud vardiat erlmcardiugrapky is an important resource. the procedure should be readily' available and pe .formed by tined a and experienced sonographer . Interrogation of fire fetal heart is routinely undertaken when a parent )especially the mother) or a previous offspring has congenital heart disease . A normal fetus reassures the parents . An abnormal fetus provides a basis for confronting difficult personal and profeniunal decisions, Conclusions. Women with congenital heart disease may he at higher risk during their pregnancy, but if they survive . usually Ihut not invariably) there are no significant harmful long-term effects. One of the best ways of simplifying medical management and reducing maternal risk is for reparative surgery to precede conception . "Animal reproduction is accomplished with inconvenience to the mother, tenacity
JACI V,,I. Ill Augwl 1991 111-a :
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.A-11 hear Jbe,i a I`lxx ." .1-' .
oftheICIII" antic1 :'-, PC] ,llvrniecnuoyhelueentheloo K . Pregnancy anJ -onllcnilal heir I di,casc arc no c3
ew 01 519 -- . Br 1 Oh,.,, 61131431
1339manngenlrdhe .1nJno,e .In PerWn 7K.CnilIS .
C,1ng0n11o1 H0ur1 14--0h References 1 Pcrlull JK Pn
cpiion Ill .
0,11 t L~r Jn1 In' 11,11 .1,1d 1, .1 He311It,.,d .r~''93Jr~rh1 .1~CIP5,1nJer,, 12. Sia-arl PN, 11.1rnan Ji' I .1n~. KI . Ho1k 11 . Prcenxul r, .mnl~ o~J h,
J. I'Ilkm KM PHI11111K. he+v
In AJnh, . Phd3Jrlphi4 WB
In . 11e:d1 CIII Prekmxncy Ann In,- M¢J ,9 ;112'314 114 . K1u,
r- \IClr~nd 1. Slcinullc IH . 13rm4 K- 1131x011 I!9 .Ma13411.', :r,43) >lo,lon :LAO, H'o' 19(II,