Prospective evaluation of circumferential and longitudinal strain in asymptomatic children with dual ventricles who underwent single ventricle repair: comparison to single LV, single RV and normal hearts

Background Rarely, patients with normally sized RV and LV will undergo total cavopulmonary connection (TCPC) due to the complexity of their intracardiac anatomy giving them a dual ventricle (DV) for a single cardiac output. The ventricular function in this unique physiology compared to SRV, SLV and normal hearts remains poorly understood, with few studies performed. In this study, we perform a comprehensive comparison of global and regional strain in both the circumferential (ecc) and longitudinal (eL) dimensions to conventional SV hearts and normal hearts.

Prospective evaluation of circumferential and longitudinal strain in asymptomatic children with dual ventricles who underwent single ventricle repair: comparison to single LV, single RV and normal hearts Ramkumar Krishnamurthy 2 , Cory V Noel 1* , Amol Pednekar 3 , Ricardo Pignatelli 1 , Rajesh Krishnamurthy 2 From 18th Annual SCMR Scientific Sessions Nice, France. 4-7 February 2015 Background Rarely, patients with normally sized RV and LV will undergo total cavopulmonary connection (TCPC) due to the complexity of their intracardiac anatomy giving them a dual ventricle (DV) for a single cardiac output. The ventricular function in this unique physiology compared to SRV, SLV and normal hearts remains poorly understood, with few studies performed 1-3 . In this study, we perform a comprehensive comparison of global and regional strain in both the circumferential (ε cc ) and longitudinal (ε L ) dimensions to conventional SV hearts and normal hearts.

Purpose
In normal subjects and asymptomatic patients with DV (LV and RV calculated independently), SLV and SRV after TCPC, to compare: 1) Global ε cc and ε L strain, 2) Regional circumferential and longitudinal strains at free wall (ε cc-free, ε L-free ) and septum (ε cc-sept, ε L-sept ), 3) ε cc and ε L across the ventricle from apex to base.

Acquisition Protocol
Strain information was acquired at three short axis slices at basal, mid-cavity, and apical locations in all 123 subjects in a 1.5T MRI scanner (Philips Acheiva) using: a) Complementary Spatial Modulation of Magnetization (CSPAMM) images: Used for generating ε cc ; and b) Fast-Strain Encoded (fSENC) images: Used for generating ε L .

Data Analysis
ε cc and ε L were calculated from SAX slices using Diagnosoft TM . The ventricular regions at each slice were assigned based upon the AHA 16 segment model ( fig. 1). ε cc-sept, ε L-sept , ε cc-free, and ε L-free were also calculated for each slice and compared.

Results
1.) Compared to normals, there is a significant reduction in global ε cc at all ventricular levels of DV patients (fig 2).
2.) Compared to normals, there is a significant reduction in global ε L in mid-ventricular and apical locations of DV patients.
3.) The ε cc of the LV of DV patients consistently lower than SLV for global and regional calculations.
4.) In the same DV patient at the basal location, the ε cc-free was higher in the RV (75 +/-42%), with the ε L-free being higher in the LV (25 +/-10%).
5.) Global ε L progressed from base to apex in all groups.  Bar plots comparing the longitudinal(ε L ) and circumferential (ε cc ) strain values in a pediatric population betweennormal subjects, patients with dual ventricles wih single ventricular repair and patients with systemic single ventricles. We demonstrate a significant reduction in both ε L and ε cc compared to normal.