Two-Dimensional Global Longitudinal Strain Rate Is a Preload Independent Index of Systemic Right Ventricular Contractility in Hypoplastic Left Heart Syndrome Patients After Fontan Operation

Abstract

Background— Assessment of systemic right ventricular (RV) function in patients with hypoplastic left heart syndrome is important during long-term follow-up after Fontan repair. Traditional echocardiographic parameters to evaluate systolic ventricular function are affected by loading conditions. The only generally accepted load-independent parameter of systolic function, end systolic elastance ( E es ), requires invasive catheterization. Therefore, we sought to determine if parameters obtained by 2-dimensional speckle tracking (2DST) were affected by acute changes in preload and correlated with catheterization-derived indices of RV contractility in hypoplastic left heart syndrome patients after Fontan palliation. Methods and Results— Fifty-two patients with hypoplastic left heart syndrome (median age, 6.6; range 2.9–22.2 years) were prospectively enrolled to have echocardiography and conductance catheter studies performed simultaneously. We compared traditional echo, 2-dimensional speckle tracking and catheterization-derived parameters during different states of preload at baseline and during dobutamine infusion. Global longitudinal strain (S) showed a tendency to decrease with preload reduction, whereas global longitudinal strain rate (SR) did not change (S: −17.7±3.4% versus −16.9±3.8%, P =0.08; SR: −1.30±0.29 versus −1.34±0.34 s −1 , P =0.3). S did not change with dobutamine infusion (−17.7±3.4% versus −18.4±3.9%, P =0.24), whereas SR increased significantly (−1.30±0.29 versus −2.26±0.49 s −1 , P <0.001). RV E es correlated with SR ( r s = −0.47, P <0.001), but not with S ( r s =0.07, P =0.5) or other echocardiographic parameters. Conclusions— In contrast to S, SR was not affected by preload and correlated with E es of the systemic RV. SR may be a useful noninvasive surrogate of RV contractility and suitable for follow-up of patients with hypoplastic left heart syndrome after Fontan palliation.