SUBJECTS AND METHODS: Database of 3,176 patients diagnosed with PSVT excluded atrial flutter or atrial fibrillation and referred for electrophysiologic study from 1986 to 2004 was retrospectively analyzed. The mechanisms of PSVT were classified as: WPW syndrome (WPW), atrioventricular reentrant tachycardia (AVRT) due to a concealed bypass tract (CBT), atrioventricular nodal reentrant tachycardia (AVNRT), atrial tachycardia (AT).

RESULTS: The mean age was 40.7±16.0 (1-90) and 53.3% of the patients were male. The mean age of females was significantly higher than males. (43.0±16.1 vs. 38.6±15.6, p<0.001) Overall, the dominant mechanism of tachycardia was AVRT at 62.6% (WPW: 31.1%, CBT: 31.5%), compared to AVNRT at 34.1 and AT at 3.1%. This was mainly due to the predominance of AVRT (74.2%; WPW: 38.1%, CBT: 361%) in male. The mechanisms of PSVT differed according to gender with 63.2% (1257/1988) of AVRT patients being males where as 64.6% (700/1084) of the AVNRT patients were females. The distribution of PSVT mechanisms differed according to gender. In males, the proportions of AVNRT : CBT : WPW were 22.7 : 36.1 : 38.1%, whereas in females the proportion was 47.2 : 26.3 : 23.0%. Age had a significant influence upon the mechanism of PSVT in both genders with an increasing proportion of AVNRT and a decreasing proportion of AVRT in the older age groups. AVRT was the dominant mechanism of PSVT in all age groups for males, where as AVNRT was the dominant mechanism of PSVT for females over 50 years of age.

CONCLUSION: The mechanism of PSVT differs significantly according to age and gender. This may be due to the increased degeneration of accessory pathway with age and difference in the conduction properties of the accessory pathway according to gender. In Koreans, the overall dominant mechanism of PSVT was AVRT mainly due to it a greater male population.