Transverse strain predicts exercise capacity in systemic right ventricle patients.
BACKGROUND
Because transposition of great arteries (TGA) patients who underwent atrial switch repair (AS) remain asymptomatic for decades before development of symptomatic heart failure, there may be some clinical value to preclinical detection of ventricular dysfunction. Detection of systemic right ventricular (RV) dysfunction in patients who are asymptomatic may prompt early initiation of heart failure therapy and more frequent clinical follow-up.


OBJECTIVE
The objective of this study was to characterize longitudinal and transverse systolic function of the systemic RV using two-dimensional (2D) strain in patients with TGA after AS repair and to correlate these parameters with their exercise capacity.


METHODS
The study population consisted of 26 patients (20±6 years) with TGA after AS operation. Conventional echocardiography and bidimensional strain were performed on consecutive patients reporting to the out patient congenital heart disease clinic. Twenty-four healthy, age-matched individuals were used as control subjects. Analysis was performed on the non-systemic RVs of the control group. All the studied patients underwent treadmill exercise testing according to the Bruce II protocol.


RESULTS
RV longitudinal 2D-strain in controls showed a base to apex gradient, while in patients was homogeneously reduced. Also RV transverse strain (i.e the radial deformation assessed by the apical 4 chamber view) showed a base to apex gradient in controls, while in patients was significantly increased in the mid and apical segments. In the systemic RV free wall, transverse strain was greater than longitudinal strain (p<0.0001), opposite from findings in the normal RV free wall (p: NS). Of interest, in AS-TGA patients we found a strong correlation between RV transverse 2D strain and exercise capacity (p<0.0001; R: 0.80). At multivariate analysis (including age, degree of tricuspid regurgitation, TAPSE, RV area fractional change, RV visually estimated ejection fraction, RV global longitudinal strain and RV global transverse strain) the best predictor of exercise capacity in AS-TGA patients was transverse 2D strain (p<0.0001).


CONCLUSIONS
In AS-TGA patients there is a shift from a predominant longitudinal shortening to a predominant transverse thickening. The transverse thickening assessed by 2D transverse strain is correlated to exercise capacity of these patients. In the follow up of AS-TGA patients the monitoring of RV transverse myocardial deformation properties should be considered more than the simple evaluation of RV longitudinal function.
Di Salvo
Giovanni
G
Second University of Naples, Chair of Cardiology, Pediatric Cardiology, Monaldi Hospital, Italy. Electronic address: giodisal@yahoo.it.
Pacileo
Giuseppe
G
Second University of Naples, Chair of Cardiology, Pediatric Cardiology, Monaldi Hospital, Italy.
Rea
Alessandra
A
Second University of Naples, Chair of Cardiology, Pediatric Cardiology, Monaldi Hospital, Italy.
Limongelli
Giuseppe
G
Second University of Naples, Chair of Cardiology, Pediatric Cardiology, Monaldi Hospital, Italy.
Baldini
Luca
L
Second University of Naples, Chair of Cardiology, Pediatric Cardiology, Monaldi Hospital, Italy.
D'Andrea
Antonello
A
Second University of Naples, Chair of Cardiology, Pediatric Cardiology, Monaldi Hospital, Italy.
D'Alto
Michele
M
Second University of Naples, Chair of Cardiology, Pediatric Cardiology, Monaldi Hospital, Italy.
Sarubbi
Berardo
B
Second University of Naples, Chair of Cardiology, Pediatric Cardiology, Monaldi Hospital, Italy.
Russo
Maria Giovanna
MG
Second University of Naples, Chair of Cardiology, Pediatric Cardiology, Monaldi Hospital, Italy.
Calabrò
Raffaele
R
Second University of Naples, Chair of Cardiology, Pediatric Cardiology, Monaldi Hospital, Italy.
D000293:Adolescent; D000328:Adult; D015444:Exercise / Q000502:physiology*; D006352:Heart Ventricles / Q000002:abnormalities / Q000503:physiopathology*; D006801:Humans; D011237:Predictive Value of Tests; D014188:Transposition of Great Vessels / Q000503:physiopathology*; D018497:Ventricular Dysfunction, Right / Q000503:physiopathology*; D055815:Young Adult