LV Dysfunction in WPW Syndrome. Introduction: Echocardiographic studies have shown that some patients with Wolff-Parkinson-White (WPW) syndrome have myocardial dyskinesia in the segments precociously activated by an accessory pathway (AP). The aim of the present study was to determine the extent to which the AP contributes to global left ventricular (LV) dysfunction.
Methods: Electrophysiological and echocardiographic data from 62 children with WPW (age at diagnosis = 5.9 ± 4.2 years) were retrospectively analyzed.
Results: The left ventricular ejection fraction (LVEF) of patients with septal APs (53 ± 11%) was significantly lower than that of patients with right (62 ± 5%) or left (61 ± 4%) APs (P = 0.001). Compared to patients with normal septal motion (n = 56), patients with septal dyskinesia (n = 6) had a reduced LVEF (61 ± 4% and 42 ± 5%, respectively) and an increased LV end diastolic dimension (P < 0.001 for both comparisons). Multivariate analysis identified septal dyskinesia as the only significant risk factor for reduced LVEF. All 6 patients with septal dyskinesia had right septal APs, and a preexcited QRS duration that was longer than that of patients with normal septal motion (140 ± 18 ms and 113 ± 32 ms, respectively; P = 0.045). After RFA there were improvements in both intraventricular dyssynchrony (septal-to-posterior wall motion delay, from 154 ± 91 ms to 33 ± 17 ms) and interventricular septal thinning (from 3.0 ± 0.5 mm to 5.3 ± 2.6 mm), and a significant increase in LVEF (from 42 ± 5% to 67 ± 8%; P = 0.001).
Conclusion: The dyskinetic segment activated by a right septal AP in WPW syndrome may lead to ventricular dilation and dysfunction. RFA produced mechanical resynchronization, reverse remodeling, and improvements in LV function. (J Cardiovasc Electrophysiol, Vol. 21, pp. 290–295, March 2010)