Matthias Grothoff MD, Presenter: Nothing to Disclose

Antje Fleischer MD, Abstract Co-Author: Nothing to Disclose

Janine Hoffmann, Abstract Co-Author: Nothing to Disclose

Lukas H. J. Lehmkuhl MD, Abstract Co-Author: Nothing to Disclose

Christian Luecke, Abstract Co-Author: Nothing to Disclose

Hashim Abdul-Khaliq MD, Abstract Co-Author: Nothing to Disclose

Matthias Gutberlet, Abstract Co-Author: Nothing to Disclose

Systemic right ventricular (RV) failure in adolescence and adulthood is a typical finding in patients with congenitally corrected transposition of the great arteries (ccTGA). In other systemic RVs such as in d-TGA after atrial switch (AS), excessive RV hypertrophy has been blamed for impairing RV ejection fraction. In this trial we sought to evaluate whether there is a common pathophysiology of systemic RV failure in ccTGA and d-TGA after AS by using Cardiovascular Magnetic Resonance (CMR).

Nineteen patients with ccTGA and 37 patients with d-TGA after AS were studied at a 1.5T scanner. Standard cine steady-state-free-precession sequences in short axis orientation were used to obtain biventricular myocardial masses and function. Patient parameters were compared to an age matched control group of 25 healthy volunteers.

RV end diastolic volume index (EDVI) of both patient groups was higher compared with both RV-EDVI and LV-EDVI of controls (p<0.001). There was no significant difference between RV-EDVI of ccTGA and d-TGA patients. Both patient groups showed an impaired RV ejection fraction (EF) compared with RV-EF of controls (p=0.02 for ccTGA; p=0.03 for d-TGA) and LV-EF of controls (p<0.001 for ccTGA; p<0.001 for d-TGA). Although ccTGA patients were significantlay older compared to d-TGA patients, there was a trend to higher RV-EFs in the ccTGA group. There was a clear tendency of higher RV MMI in the ccTGA group compared with the d-TGA group but, in contrast to the latter, no correlation between RV myocardial mass index and RV-EF.

Although ccTGA patients were older and demonstrated with higher RV-MMIs, systemic RV function was better compared with d-TGA after AS. In particular, high degree RV hypertrophy does apparently not harm RV function. We conclude that the pathophysiology of RVs is different in part. One difference might be the postoperative situation after AS resulting in rigidness of the atria with impaired contribution to ventricular filling. Furthermore patients after AS show fibrosis of the systemic RV myocardium in CMR delayed enhancement imaging, which is probably a result of perioperative ischemia and might additionally impair EF. Perioperative ischemia however does not exist in ccTGA patients.

Differences of systemic RVs in ccTGA and d-TGA have to be considered when evaluating the cardiac  status in follow-up examinations.

Grothoff, M, Fleischer, A, Hoffmann, J, Lehmkuhl, L, Luecke, C, Abdul-Khaliq, H, Gutberlet, M, The Systemic Right Ventricle in Congenitally Corrected Transposition of the Great Arteries Is Different from the Right Ventricle in d-Transposition after Atrial Switch: A Cardiovascular Magnetic Resonance Study.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11015278.html