Diastolic dysfuction can be assessed by Doppler echocardiography of mitral inflow. Multiple factors including atrioventricular (AV) delay affect the mitral inflow Doppler indexes. This study was designed to assess the changes of mitral inflow patterns after successful radiofrequency catheter ablation (RFCA) of accessory pathway associated with a short AV interval during pre-excitation in patients with WPW syndrome.

Echocardiogram, ECG and BP were recorded before and after RFCA for treatment of accessory pathway in 15 patients with WPW syndrome (mean age : 39.7±14.6). Doppler indexes including E wave velocity and its velocity time integral (EVTI) ,A wave velocity and its VTI (AVTI), deceleration time (DT), isovolumic relaxation time (IVRT), atrial filling fraction (AFF)and total mitral inflow VTI were measured.

1) PR interval prolonged 94±18msec to 174±34msec (p<0.001) without significant increment of heart rate and blood pressure after successful RFCA. 2) E/A ratio decreased from 1.29±0.58 to 1.1±0.53 (<0.001) but E wave velocity, DT and IVRT were not changed significantly after RFCA. 3) A wave velocity and AFF was 55.8±17.4msec and 0.35±0.08 and increased to 61.8±19.9msec and 0.42±0.1, respectively after RFCA (p<0.05). 4) Total mitral inflow VTI was 13.6±3.5cm and 14.9±3.6cm before and after RFCA, respectively (p<0.05).

These results suggested that normalization of the PR interval after RFCA in patients with WPW syndrome had beneficial hemodynamic effects on the stroke volume by changing mitral inflow Doppler indexes. Therefore, the effect of AV delay is an another parameter to consider when evaluating Doppler indexes of LV filling.