Cardiothoracic ratio may be misleading in the assessment of right- and left-ventricular size in patients with repaired tetralogy of Fallot.
OBJECTIVE
To assess the relationship between cardiothoracic ratio (CTR) and ventricular and atrial volumes in patients with repaired tetralogy of Fallot (TOF).


METHODS
Patients with repaired TOF undergoing cardiac magnetic resonance (CMR) and chest radiography within 1 day were included (n = 82; median age: 24.7 years, interquartile range: 21.5-35.9). The CTR was obtained from upright posteroanterior chest roentgenograms. Analyses of CMR images and radiographs were performed in a blinded fashion.


RESULTS
There were 35.1% (13/37) of patients with normal CTR (<0.5) who had severe right ventricular (RV) dilatation. There were six patients (13.3%, 6/45) with high CTR with both normal RV and left-ventricular (LV) volumes. CTR did not correlate with either RV or LV volumes but showed a weak correlation with right- and left-atrial volumes (r = 0.43, p = 0.0001; r = 0.27, p = 0.01, respectively). CTR ≥0.5 showed poor ability in the identification of severe RV dilatation (sensitivity: 61.8%, specificity: 50%). The combination of CTR and signs of RV enlargement on lateral radiographs did not improve the diagnostic accuracy of any of those parameters alone.


CONCLUSIONS
CTR in patients with repaired TOF reflected atrial rather than ventricular dilatation. The use of CTR or lateral radiographs in patients with repaired TOF may lead to false conclusions concerning ventricular size.
Magnetic Resonance Unit, Institute of Cardiology, Warsaw, Poland; Department of Radiology, Institute of Cardiology, Warsaw, Poland; Department of Coronary Artery Disease and Structural Heart Diseases, Institute of Cardiology, Warsaw, Poland. Electronic address: mspiewak@ikard.pl.
M
M
Spiewak
Magnetic Resonance Unit, Institute of Cardiology, Warsaw, Poland; Department of Interventional Cardiology and Angiology, Institute of Cardiology, Warsaw, Poland.
L A
LA
Małek
Department of Congenital Heart Diseases, Institute of Cardiology, Warsaw, Poland.
E K
EK
Biernacka
Department of Congenital Heart Diseases, Institute of Cardiology, Warsaw, Poland.
M
M
Kowalski
Department of Radiology, Institute of Cardiology, Warsaw, Poland.
I
I
Michałowska
Department of Congenital Heart Diseases, Institute of Cardiology, Warsaw, Poland.
P
P
Hoffman
Magnetic Resonance Unit, Institute of Cardiology, Warsaw, Poland; Department of Radiology, Institute of Cardiology, Warsaw, Poland.
J
J
Miśko
Department of Coronary Artery Disease and Structural Heart Diseases, Institute of Cardiology, Warsaw, Poland.
M
M
Demkow
Institute of Cardiology, Warsaw, Poland.
W
W
Rużyłło
Magnetic Resonance Unit, Institute of Cardiology, Warsaw, Poland; Department of Radiology, Institute of Cardiology, Warsaw, Poland.
M
M
Marczak
D000328:Adult; D000704:Analysis of Variance; D004108:Dilatation, Pathologic / Q000473:pathology; D005260:Female; D006325:Heart Atria / Q000473:pathology; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D009929:Organ Size / Q000502:physiology; D011183:Postoperative Complications / Q000473:pathology*; D012680:Sensitivity and Specificity; D013318:Stroke Volume / Q000502:physiology; D013771:Tetralogy of Fallot / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D014057:Tomography, X-Ray Computed; D055815:Young Adult