Kinoshita S, Konishi G
Health Administration Center, Hokkaido University, Sapporo, Japan.
J Electrocardiol. 1987 Jul;20(3):272-9. doi: 10.1016/s0022-0736(87)80026-2.
In 37 athletes with atrioventricular (AV) Wenckebach periodicity, the relationship between PP and RR intervals was investigated. In most athletes, when PP intervals gradually lengthened, RR as well as PR intervals usually also gradually lengthened until a blocked P wave occurred, resulting in the occurrence of an atypical Wenckebach period with prolongation of the last RR interval (variant I). In 20 athletes, sudden marked prolongation of a PR interval occasionally occurred, which was usually followed by a blocked P wave (variant II). In five athletes, once sudden marked prolongation of a PR interval occurred, markedly long PR intervals were maintained for some time, and then a PR interval suddenly shortened without a blocked P wave (variant III). It appeared that the above findings were caused by spontaneous variations in vagal tone. It was suggested that longitudinal dissociation and concealed reentry in the AV node occurred in atypical Wenckebach periods of variants II and III, but not in the other periods.
