Myocardial work efficiency in children with Wolff-Parkinson-White preexcitation before and after accessory pathway...

Ventricular preexcitation alters the electromechanical activation sequence and may induce left ventricular (LV) contractile discoordination and pathologic remodeling. We aimed to evaluate LV myocardial work (MW) before and after accessory pathway (AP) ablation and to compare it to controls in a prospective observational study.

MW calculation was performed in 37 pediatric patients with Wolff-Parkinson-White preexcitation before and within 24 h after catheter ablation using a commercial software. MW was calculated as the area under pressure-strain loop derived from speckle tracking echocardiography and blood pressure. Thirty healthy age- and weight-matched individuals were used as controls.

Before ablation LV ejection fraction (mean 55.3 in patients vs. 59.3% in controls, P = 0.005) and global LV MW efficiency (median 93.0 vs. 95.0%, P < 0.001) were lower in patients vs. controls. Global LV MW efficiency correlated negatively with QRS duration (R = 0.519, P < 0.001) and the interval between earliest delta wave onset and R wave peak in lead V6 (R = 0.705, P < 0.001), respectively. Segmental LV MW efficiency increased from median 93.0% at AP location to 97.0% in distant segments (P < 0.001). After successful ablation (N = 31/37 patients) global LV MW efficiency increased from mean 91.8 to 93.6% (P = 0.013) and segmental efficiency was more equally distributed (P < 0.001) with increase in segments adjacent to ventricular AP insertion (P = 0.006).

Ventricular preexcitation is associated with decreased LV MW efficiency which correlates negatively with the degree of preexcitation and improves early after ablation. Wasted work in asymptomatic preexcitation may be considered when assessing the potential for pathologic LV remodeling or discussing the indication for prophylactic ablation.