Effect of chronic right ventricular volume overload on ventricular interaction in patients after tetralogy of Fallot repair.
BACKGROUND
Right ventricular (RV) volume overload results in RV dilatation and dysfunction in patients with pulmonary regurgitation after tetralogy of Fallot (ToF) repair, affecting left ventricular (LV) function because of ventricular interaction. The aim of this study was to assess the effect of chronic RV volume loading on LV myocardial mechanics in patients after ToF repair by combining cardiac magnetic resonance imaging with echocardiography.


METHODS
Seventy-five subjects were studied: 50 patients after ToF repair and 25 age-matched controls. All patients with ToF and controls underwent echocardiography at the time of clinically indicated cardiac magnetic resonance imaging. Myocardial deformation, including LV torsion, was analyzed using speckle-tracking echocardiography.


RESULTS
RV free wall global and segmental longitudinal strain and strain rate were significantly lower in patients with ToF compared with controls (P < .001). All LV longitudinal, strain, and torsion parameters were significantly reduced in patients with ToF (P < .01). Basal rotation was particularly abnormal, with 38% of patients with ToF having reversed basal rotation. In contrast, apical rotation was reduced but not reversed. On multivariate regression analysis, the only significant predictor of counterclockwise basal rotation was RV strain, suggesting that RV function more than dilatation influences abnormal LV torsion.


CONCLUSIONS
Patients with ToF have abnormal LV myocardial mechanics, as demonstrated by speckle-tracking echocardiography. The most striking changes were noted in LV torsion, especially related to abnormal LV basal rotation. RV dysfunction seems the most important determinant of abnormal LV rotation. The clinical significance and potential prognostic implications of these observations remain to be determined.
Division of Cardiology, Labatt Family Heart Centre, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
Andreea
A
Dragulescu
Division of Cardiology, Labatt Family Heart Centre, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
Mark K
MK
Friedberg
Division of Cardiology, Labatt Family Heart Centre, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada; Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada.
Lars
L
Grosse-Wortmann
Division of Cardiology, Labatt Family Heart Centre, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
Andrew
A
Redington
Division of Cardiology, Labatt Family Heart Centre, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada. Electronic address: luc.mertens@sickkids.ca.
Luc
L
Mertens
D000293:Adolescent; D006348:Cardiac Surgical Procedures; D002648:Child; D015150:Echocardiography, Doppler / Q000379:methods*; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D008297:Male; D011184:Postoperative Period; D011379:Prognosis; D011446:Prospective Studies; D013318:Stroke Volume; D013771:Tetralogy of Fallot / Q000601:surgery*; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D016278:Ventricular Function, Right / Q000502:physiology*
Left ventricular torsion; Tetralogy of Fallot; Ventricular interaction