wall deficiency, may result in an increased rate of successful occlusion.“~13 Although speculative, the possible risk of paradoxic embolism through such residual lesions in this popu- lation has been suggested. Whereas the isolated patent foramen ovale, per se, is not considered a cause of peripheral embolism in the adult population, I4 there is evidence that massive, early passage of contrast through a patent foramen ovale during transesophageal echocardiography may predispose to paradoxic em- bolism.15 Yet, the risk of this complication, in the pop- ulation with a patent for-amen ovale is unknown, and whether those patients with residual leaks will require further intervention is speculative. Supraventricular arrhythmias have not been a sig- nificant adverse event in this small patient cohort, with only 1 patient having a minor dysrhythmia that required no therapy. Although these findings are en- couraging, it is unknown if the long-term incidence of atria1 dysrhythmias will be less than for surgical repair, where the risk is thought to be a combination of disturbed atria1 function secondary to right ven- tricular volume overload and surgical trauma.‘6.‘7 The incidence of device arm fractures was similar to that previously reported, 2,7,8 and Kaplan-Meier analysis suggested that this will continue to increase. Importantly, however, this design flaw, which re- sulted in withdrawal of the device from clinical tri- als, has not resulted in clinical complications, device embolization, or influenced the rate of complete oc- clusion of atria1 defects. These results indicate that transcatheter occlu- sion of the ASD with the double umbrella device is safe and effective in reducing hemodynamically sig- nificant shunts. 1. King TD, Mills NL. Secundum atrial septal defects: Non-operative closure during cardiac catheterization. JAMA 1976;235:2506-2509. 2. Perry SB, van der Velde ME, Bridges ND, Keane JF, Lock JE. Tramcatheter closure of atria1 and ventricular septal defects. Her-z 1993;18:135- 142. 3. Rao PS, Stderis EB, Hausdorf G, Rey C, Lloyd TR. 13eekman RH, Worms AM, Bourlon F, Onorato E, Khalilullah M, Haddad .I. International experience with secundum atria1 septal defect occlusion by the buttoned device. Am Hean J 1994;128:1022-1035. 4. Redington AN, Rigby ML. Transcatheter closure of interatrial communica- tions with a modified umbrella device. Er Heart J 1994;‘72:372-377. 5. Galal MO, Wobst A, Hatle HL, Schmaltz AA, De Vol KE, Fawzy ME, Abbag F, Fadley F, Duran CM. Pen-operative complications following surgical closure of atria1 septal defect type II in 232 patients-a baseline study. Eur Heart J 1994;15:1381-1384. 6. Rome JJ, Keane JF, Perry SB, Spevak PJ, Lock JE. Double-umbrella closure of attial defects: initial clinical applications. Circulation 1990;82:104-1045. 7. Bridges ND, Hellenbrand W. La&on L, Filiano J, Newburger NW, Lock JE. Transcatheter closure of patent foramen ovale after presumed paradoxical em- bolism. Circulation 1992;86: 1902- 1908. 8. Koike K, Echigo S, Kumate M, Kobayashi T, Isoda T, Ishii M, Ishizawa A, Kamiya T, Kato H. Transcatheter closure of atria1 septal defect with a prototype clamshell septal umbrella: one year follow-up. J Cardioi 1994;24:53-60. 9. Boutin C, Musewe NN, Smallhorn JF, Dyck JD, Kobayashi T, Benson LN. Echocardiographic follow-up of atria1 septal defect after catheter closure by double-umbrella device. Circularion 1993;88:621-627, 10. Meyer RA. Pediatric Echocardiography. Philadelphia: Lea & Febiger 1977:291-294. I I. Reddy SC, Rao PS, Ewenko J, Koscik R, Wilson AD. Echocardiographic predictors of success of catheter closure of atria1 septal defect with the buttoned device. Am Heart J 1995;129:76-82. 12. Ferreira SM, Ho SY, Anderson RH. Morphologic study of defects of the atria.1 septum within the oval fossa: implications for transcatheter closure of left- to tight shunt. Br Heart J 1992;67:316-320, 13. Rosenfeld HM, van der Velde ME, Sanders SP, Cola” SD, Parness IA, Lock JE, Spevak PJ. Echocardiographic predictors of candidacy for successful trans- catheter atria1 septal defect closure. Cather Cardiovasc Diagn 1995;34:29-34. 14. Vandenbogeraerde J, De Bleeker J, Decoo D, Francois K. Cambier B, Ber- gen JM, Vandermersch C, De Reuck J, Clement DL. Transoesophageal echo- Doppler in patients suspected of a cardiac source of peripheral emboli. Eur Heart J 1992:13:88-94. 15. Van Camp G, Schulze D, Cosyns B, Vandenbossche JL. Relation between patent foramen ovale and unexplained stroke. Am J Cardiol 1993;71:596-598. 16. Murphy JG, Gersh BJ, McGoon MD, Mair DD, Potter CJ, Ilstrup DM, McGoon DC, Puga FJ, Kirklin JW. Danielson GK. Long-term outcome after surgical repair of isolated atria1 septal defect: follow-up at 27 to 32 years. N Engl J Med 1990;323: 1645- 1650. 17. Bolens M, Friedli 8. Sinus node function and conduction system before and after surgery for secundum atria1 septal defect: an electrophysiologic study. Am J Cardiol 1984;53: 1415- 1420. Cardiac Output Response to Dynamic Exercise After Atrial Switch Repair for Transposition of the Great Arteries Eric Page, MD, HBkne Perrault, PhD, Patrice Flare, PhD, Anne-Marie Rossignoi, MD, Sophie Pironneau, MD, Gcile Rocca, MD and Bernard Aguilaniu, MD T he impairment in maximal exercise tolerance ob- served in transposition of the great arteries (TGA) l-6 may be attributed to poor right ventricular function or residual hemodynamic abnormalities, re- sulting in an inadequate exercise-induced increase in stroke volume.2,3,7,* Controversy still exists as to the implications of this impairment in daily tasks. In the only previous study on submaximal exercise re- From UCP. X, laboratoire de physiopathologie de l’exerclce, Gre- noble, France. Dr. Page’s address is: UCP.X, 4.5 Avenue Marie Rey- noard, 38 100 Grenoble, France. Manuscript received September 13, 1995; revised manuscript received and accepted November 21, 1995. 892 THE AMERICAN JOURNAL OF CARDIOLOGY@ VOL. 77 sponse after TGA repair, a normal cardiac output was observed at 50% of maximal oxygen consump- tion4 Because cardiac output was only determined at a single low exercise intensity level, it is difficult to conclude in favor of normal submaximal cardiac output typical of daily tasks and physical activities. Therefore, we compared the cardiac output response to 2 successive levels of moderate and intense sub- maximal exercise in patients who underwent d-TGA (selected for their good postsurgical success) and their age-matched healthy controls. . . . Seven patients (3 boys and 4 girls, aged 10.4 +- APRIL 15, 1996