Right ventricular hypertrophy after atrial switch operation: normal adaptation process or risk factor? A cardiac magnetic resonance study.
BACKGROUND
Systemic right ventricle (RV) hypertrophy and impaired function occur after atrial switch for dextro-transposition of the great arteries (d-TGA). Echocardiography is limited in its ability to assess the RV. We sought to evaluate systemic RV myocardial-mass index (MMI) and function after atrial switch and to analyse the role of hypertrophy for ventricular function with special consideration of the interventricular septal (IVS) movement.


METHODS
Thirty-seven consecutive patients (median age 22.9 years) after atrial switch were studied using cardiac magnetic resonance imaging (1.5T Intera, Philips) with a dedicated 5-channel phased-array surface cardiac coil. Cine steady-state free-precession sequences were acquired to obtain myocardial masses and function. The systolic movement of the IVS was defined as positive when moving towards the centroid of the RV and was defined as non-positive otherwise. Patient parameters were compared to controls.


RESULTS
The systemic RVs were significantly larger (p < 0.001) than the left ventricles of the control group, systolic function was significantly impaired (p < 0.001) and MMI including the IVS was comparable (p = n.s.). RV-MMI excluding the IVS and RV ejection fraction (EF) demonstrated a quadratic correlation (r = 0.6, p < 0.001), meaning that patients with RV-MMI ≤29 g/m(2) and >68 g/m(2) had a reduced level of systolic function. Positive septal movement improved RV function compared with non-positive septal movement (p = 0.024).


CONCLUSIONS
There seems to be a range of beneficial RV hypertrophy after atrial switch in which a sufficient RV-EF can be expected. A positive septal movement, probably the result of hypertrophic septal RV fibres, improves RV function and might be regarded as a beneficial contraction pattern.
Department of Diagnostic and Interventional Radiology, Heart Center, University of Leipzig, Strümpellstr. 39, 04289, Leipzig, Germany. grothoff@gmx.de
Matthias
M
Grothoff
Janine
J
Hoffmann
Hashim
H
Abdul-Khaliq
Lukas
L
Lehmkuhl
Ingo
I
Dähnert
Felix
F
Berger
Meinhard
M
Mende
Matthias
M
Gutberlet
D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D017380:Hypertrophy, Right Ventricular / Q000209:etiology*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D014188:Transposition of Great Vessels / Q000601:surgery*; D016278:Ventricular Function, Right; D054088:Ventricular Septum / Q000378:metabolism; D055815:Young Adult