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.

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 (Ees), 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 Ees correlated with SR (rs= -0.47, P<0.001), but not with S (rs=0.07, P=0.5) or other echocardiographic parameters.

CONCLUSIONS: In contrast to S, SR was not affected by preload and correlated with Ees 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.