Aims: The purpose of this study was to investigate the relationship between the incidence of dual atrioventricular (AV) nodal pathways and age. Age-related changes in the AV node electrophysiological properties have rarely been investigated. AV nodal re-entrant tachycardia is more frequent in the young than in the elderly.
Methods and results: From 1988 to 1998, premature atrial stimulation was performed in 1,435 patients referred to our institution for transoesophageal electrophysiological study. 1,276 patients (89%) with a diagnosis of ventricular pre-excitation, supraventricular arrhythmia or AV block were excluded. The study cohort consisted of the remaining 159 patients (11%) of the whole group) referred for syncope (8.2% of the subgroup), suspected ventricular pre-excitation (10.7%), suspected sinus node dysfunction (52.8%) or undetermined palpitations (28.3%). The 159 study patients were divided into 3 groups according to age: group A (11-30 years, 50 patients), group B (30-60 years, 35 patients) and group C (>60 years, 74 patients). A dual AV nodal pathway was found in 16 patients of group A (32.0%), 6 patients of group B (17.1%) and 8 patients of group C (10.8%), the difference between group A and group C being significant (P<0.05).
Conclusion: The incidence of dual AV nodal pathways decreases with ageing, suggesting that the AV node undergoes age-related electrophysiological changes. This finding could explain the uncommon onset of AV nodal re-entrant tachycardia in the elderly.