The article by Coumbe et al1 in this journal is most welcome. It throws more light on a vexed difference between North American and European pacemaker practice, where the two regions’ guidelines for pacemaker implantation differ profoundly.2–4 Mobitz type 1 atrioventricular block (AVB) in North America is classified as a Class 3 indication in the most recent guidelines for permanent pacing2 unless the block is demonstrated on electrophysiological study to be below the his bundle. In practice, however, electrophysiological assessments are rarely performed. Furthermore, a very recent focused update of the North American guidelines does not change the above recommendation.3 By contrast, the European Society of Cardiology (ESC) guidelines4 published closely related in time to the full North American version2 recommends pacing as a Class 2A indication.

The discrepancy between current North American and European recommendations is based, first, on the correct observation of the benign nature of Mobitz type 1 second degree AVB in younger patients especially when it occurs during sleep. Second, there has been an apparent dismissal in North America of the European evidence from the Devon Heart study,5 ,6 which demonstrated that the mortality in older patients (≥69 years) with Mobitz type 1 AVB is not different from Mobitz type 2 AVB5 and, moreover, improved survival in paced patients in this same age group with Mobitz type 1 AVB compared with those unpaced.6 This dismissal of evidence from the Devon Heart study is likely to be due to its registry form with there being no available clinical trial. Nevertheless, the observations are important and the original 1985 Devon Heart study observations were the subject of a perceptive and emphatic Editorial published simultaneously in this journal by the late Ronnie Campbell. …