ABSTRACTS

ECHOCARDIOGRAPHIC FEATURES OF ENDOCARDIAL CUSHION DEFECT Roberta Williams, M.D., Michael Rudd, B.S., M.A., The Children's Hospital Medical Center, Boston, Massachusetts

Endocardial cushion defect (ECD) has a wide range of anatomic presentations. Eighteen patients with ECD were studied using standard echocardiographic techniques. The specific lesions in these patients ranged from simple atria1 septal defect of the primum type with minimal mi- tral regurgitation to complete A-V canal. The most con- stant echo finding was that the plane of excursion of the anterior mitral valve leaflet (AML) was parallel to the interventricular (IV) septum rather than perpendicular to it as is seen normally. Therefore, AML excursion was not detected with the usual transducer position which dis- plays both the IV septum and the posterior left ventri- cular (LV) wall. Also, there was apparent discontinuity between the superior portion of the AML and the mitral valve ring in some patients. Presumably, this discon- tinuity occurred at the site of the cleft in the AML.

In 3 patients with complete A-V canal, a structure with a broad sinusoidal excursion was demonstrated to be continuous with and lie medial to the leftward A-V valve. Its position and movement suggest that it represents the central portion of the common anterior leaflet. Other investigators have described parallel double mitral valve ethos as representing the cleft in the AML. It has been our experience that double ethos usually repre- sent redundancy of single valve leaflets. In addition, the superior and inferior portions of the cleft AML do not usually move in the same plane.

The echocardiographic findings in ECD reflect its varied anatomic presentations. However, the most stri- king finding in this study is the abnormal relationship of the mitral valve to the IV septum, aortic annulus, and posterior LV wall.

SDlmIDR VEHA CAVA FLnxmmT ARTERY Amma4os1s

Velloe L. Willmen, M.D., Eeadrlck B. Ikrner. M.D., George C. Itioer, M.D., J.Gerard Mudd, M.D. end Leocurd P. hgea, M.D., st. Louio Ullivermity school of Medicin.. St. Lotlie. Nlowuri

Cyaaotfc coqgeaital burr dimeem due to insufficient pulmonary artaid flw bee been pellieted by l nertomoeis of rho superior vene cave to tha right pulmucry artery in 40 petientr. The lmopltal mortality wee S/16 for tricurpld l trosie. 3/10 for treaepoeition of the greet ~oeeele, b/6 for truacue l rteriomr, 2/6 for pulwnery l treoie end l/l for tetrelogy to give l horpltel mortality of 15/39 (38%). Boepltel mortality vee 617 for potimte under one month of ego, 7/16 for tbore l-6 wnthe of age and 2/16 for theme 6 month. to 16 fure of l ge. 18 14 patient. there wee prior, coacaitent or eubeequeat beading of, or vrtric hunting to the left pulmo~ry artery. There heve beeo 7 late deethe. Seventeen petleate have been followed 3-S yeere l fter the aeeetomo- l io l ed lete cathoterlmtion bad boaa obtained ia 10. Lete occurreuce of the roperfor veae ceve l yadrama or em- bolfsetion to the right lung lure not been recognized. Late ecclosion of tb l urtomomim occarred in two petienk Thie eaeatomoole reeulte in improved palmmary blood flow end qetmic oxygenation without incrueiag cerdiec work. protects tbe lunge from palmnery hypertension end ellow deftiltive eerrectloo of emenable leekme.

IMPRLJVED IMMUNOSUPPRESSION INCARDIAC ALLOGRAFTING: PROLONGED TRANSmdNT SURVIVAL WITH REDUCTION OF COMPLICA- TION RATE. Thomas,F., Wolf, J., Thomas,J., Hudson,B., and Hume,D., Medical College of Virginia & McGuire VA Hospital, Richmond, Virginia. The current one-year survival in clinical cardiac

transplants is sO$, with most postoperative deaths re- lated to (1) rejection, (2) infection, (3) drug toticity. These complications are due to the lack of potency and selectivity of the imnmnosuppressive agents used clini- cally. Results: Our studies of experimental heterotopic

cardiac transplantation in mongrel dogs using Irmran and Prednisone support previous studies demonstrating that graft survival time is only slightly prolonged (6.5 13-14 days) with 50 to 75% of the animals suffering from an infection and/or drug toxicity. Twenty-one dogs were given only horse antithynxxyte globulin (ATG) and had a graft survival time of 13.6 days with a reduced in- fection rate of only 10% and a drug toxicity rate of only 10%. Four dogs given goat ATG had a mean survival of 13.8 days and infection rate of O$ and drug toxicity rate of 0%. Four dogs given a limited course of rabbit ATG consisting only of k-5 injections had a mean survival of 35 days, an infection rate of G$, and a drug toxicity rate of C$. These studies suggest that ATG preparations result in a

lower infection rate and drug toxicity rate than Imuran and Prednisone. Most important, however, was the finding that rabbit ATG resulted in a markedly prolonged survival rate with no infection rate or drug toxicity evidenced. Continuing studies in our laboratory suggest that a longer course of rabbit ATG will prolong graft survival beyond 40 days.

OKrIB~CPAcINGIN~

Fred Zaanko,MD; LouisGuize,MD; PierreMaurice,M); Alain Garbaux,~,CardiolcqicalClinic, Boucicaut Hcspital, University of Paris, France.

The Grthcrhytlnnic Pacemaker (O.P.) is capable tc operate againatfastaswallas slow arrhythmias by using two independent “cmdsnk%d” interventicn systems inordar tc ccntrcl premature ectcpic beats without the necessity to increase the basic smlaticm frequency. The O.P. adds to the basic frequency an autanatically adaptable instantaneousbeattobeatin~~~frequencywhich delivers a single stimulation only if a premature extra- systcle or a beginning rapid tachjmrdia cccurs; two consecutive extrasystclesmay succeed one an&her sc rapidly that the semnd extrasystcle werdrives the firstautcmatically coupled rapid intervention system; inthat caseaspecialsnti-tachycardiasystefnmeasuras the interval between the two succeeding axtraeystcles and stimulates after an adjustable escape time shorter thantheprwicuslymeasured interval. If the preceding rapid single stimulaticn systenrj fail tc reduce the premature ectcpicbeata anoptional "auta~tic demxd frequencyw systemcanbe usedwhichincreases teq0- rarily and progressively the basic frequency until the ectcpic beats disappear. The clinical evaluaticn of the O.P. in 3lpatients treated in inteneivacareunitshas sha4nin sevencases an imnediatereducticnofprema- ture ectcpicbeats sndin two patients an immediate reductionofbeginningventriculartachycardiaswhereas the previous applicaticn of a "demand" pacaMker at the samebasic stlmulatian fraquencydid notccntrclthese rapid arrhythmias. Till new nc incident in relationship with the use of the O.P. has beenobserved.

January 1973 The American Journal of CARDIOLOGY Volume 31 165