eccentric ventricular mechanical activation. In clinical practice, overt LV dysfunction is not noted in patients with WPW syndrome. The aim of the study was to evaluate the functional consequences of pre-excitation induced mechanical dyssysnchrony in WPW syndrome. Methods: Transthoracic echocardiography with TD and Strain imaging prior to and after (median: 1 day) successful RFA were analysed in 16 patients with pre-excitation whose electrocardiograms were suggestive of a right free wall

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... ; n¼8) or septal accessory pathway (S-AP; n¼8). Results: There was no significant depression of LV function in both groups prior to the procedure with a fractional shortening (FS) of 35.56 ± 4.24 % and a LVEF of 64.00 ± 1.93 % in the RFWAP group and a FS of 38.53 ± 2.04 % and LVEF of 62.75 ± 1.67 % in the S-AP group (p value ¼ 0.141 and 0.147). The difference in the aortic and pulmonary pre-ejection periods e Inter Venticular Mechanical Delay (IVMD), taken as a measure of interventricular dyssynchrony was 28.63 ± 1.41 ms and 29.25 ± 3.62 ms in right free wall and septal group. Septal-to-posterior wall motion delay (SPWMD) as a global measure for LV dyssynchrony showed a decrease in both groups after successful RFA (61.25 ± 46.43 ms to 26.25 ± 36.62 ms in the right free wall group and 125.00 ± 34.64 ms to 28.75 ± 24.17 ms in the S-AP group. Further analysis with spectral TD, TVI and longitudinal/radial strain evaluated as the time difference of QRS onset to peak strain between opposing walls showed no significant intraventricular dyssynchrony. Conclusions: WPW syndromes with RFW or septal APs donot cause significant inter or intraventricular dyssynchrony and donot jeopardize global LV function even though SPWMD showed improvement after RFA in the septal AP group.