An analysis of Wenckebach periodicity.

摘要: Summary His bundle electrograms of 40 patients developing Wenckebach block during atrial pacing and four with spontaneous above the were reviewed to determine frequency classical periodicity. Thirty had 143 cycles that suitable for analysis. Cycles evaluated following features: 1) first A-H interval as shortest, 2) R-R longest, 3) last 4) a progressive diminution increment prolongation, 5) 6) containing nonconducted A wave being equal twice A-A less sum increments prolongation. occurred not significantly different from those spontaneously. Fifteen per cent all met six criteria; 14% five, 6% four; 17% three; 20% two; 27% one; 1% none. Short most likely show typical periodicity: 56% conduction ratios 4:3, 28% 5:4 4% 6:5 at least five criteria, whereas none 22 having 7:6 or greater more than three features. The shortest was common feature occurring in 98% cycles, features prolongation common, 35% cycles. These findigns indicate, therefore, periodicity is uncommon, especially when are greater. implications these observations suggested mechanisms discussed literture reviewed.