EFFORT-INDUCED ATRIOVENTRICULAR BLOCKS, B ASED ON A SERIES OF 62 CASES

Based on a retrospective study, we report the clinical and electrophys iological characteristics of 62 cases of effort-induced atrio-ventricu lar block (AVE). The diagnosis of effort-induced AVE was established b y stress test and/or Holter EGG. This series consisted of 18 women and 44 men with a mean age of 64+/-13 years. AVE presented in the form of poor adaptation to effort in 41 patients (66 %), fainting and/or pres yncope suggestive of Stokes-Adams attacks in 20 patients (32 %), assoc iated with poor adaptation to effort, except in 5 patients. 48 patient s (77 %) did not have any underlying heart disease. The ECG was normal in 25 patients (40 %) or abnormal, demonstrating a Ist degree AVE and /or an intraventricular conduction disorder. On electrophysiological i nvestigation, the AVE was type II (Mobitz II) in 48 patients (77 %), g enerally 2/1. The block was infranodal, either in or below the His bun dle, in 56 patients (90 %). When it was situated above the His bundle, it was organic and degenerative, situated at the AV node, at the node -His junction, or even proximally in the His bundle. Effort-induced AV E implies DDD atrioventricular stimulation. The presence of this anoma ly should be investigated in patients with poor adaptation to effort, but also when the clinical picture is dominated by Stokes-Adam attacks .