Anterograde and retrograde fast pathway properties were analyzed in 160 patients with anterograde dual atrioventricular (A-V) nodal pathways, with or without A-V nodal reentrant tachycardia. A-H intervals (reflecting anterograde fast pathway conduction) ranged from 46 to 234 ms (mean ± standard deviation 91 ± 30). The longest atrial paced cycle lengths at which block occurred in the anterograde fast pathway ranged from 231 to 857 ms (435 ± 112). Regression analysis of these cycle lengths versus A-H intervals revealed a correlation coefficient (r) value of 0.41 (p < 0.01). Retrograde fast pathway conduction was present (at a ventricular paced cycle length slightly shorter than sinus rhythm) in 84 of 125 patients: 15 of 16 with an A-H interval of less than 60 ms, 44 of 58 with an interval of 60 to 90 ms, 20 of 41 with an interval of 91 to 130 ms and 5 of 10 with an A-H Interval of more than 130 ms (p < 0.01). Retrograde fast pathway conduction was intact at a cycle length of 375 ms in 41 of 124 patients: 11 of 16 with an A-H interval of less than 60 ms, 22 of 57 with an interval of 60 to 90 ms, 7 of 41 with an interval of 91 to 130 ms and 1 of 10 with an A-H interval of more than 130 ms (p <0.01). Sustained A-V nodal reentrant tachycardia could be induced in 51 of 160 patients, being induced in 7 of 17 with an A-H interval of less than 60 ms, 27 of 72 with an interval of 60 to 90 ms, 15 of 59 with an interval of 91 to 130 and 2 of 10 with an interval greater than 130 ms (p < 0.05). In conclusion, in patients with dual A-V nodal pathways, there are relations between the A-H interval and the ability of the fast pathway to sustain sequential anterograde conduction, and between the A-H interval and the ability of the fast pathway to sustain sequential retrograde conduction. Among patients with dual pathways, patients with a shorter A-H interval are more likely to have A-V nodal reentrant tachycardia, because these patients are more likely to have excellent retrograde fast pathway sequential conduction (a requirement for the occurrence of reentrant tachycardia).
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine