抄録
Implantable loop recorders (ILRs) are useful to detect the cause of syncope. However, there remain problems such as inadequate amplitude of R wave (AoR) and its attenuation by postural change. To examine the relationship between AoR and postural change, we made left precordial AoR mappings with an ILR in 15 healthy men taking 7 poses (supine, prone, right and left lateral recumbent position and drop hands, raise hands and prone in a standing position). For the mapping, we divided the left anterior chest area into 15 parts (left sternal border: LSB, midclavicular line: MCL, anterior axillary line: AAL with each intercostal area: IA from 2nd to 6th IA.) and measured AoRs in 4 directions (vertical, horizontal, diagonally right upward 45 degrees: DR45, diagonally left upward 45 degrees) in each part. The lower IA AoRs were measured in, the higher those were, but too variable in 6th IA. In AAL, AoRs were lower than in LSB and MCL. AoRs were highest in DR45. Compared with spine, there were significant changes in AoR only in left lateral recumbent position and prone in a standing position. It would be recommended to place ILRs in 5th IA and in LSB or MCL, in DR45. If AoR is adequate in spine, it might be necessary to confirm that it is enough in left lateral recumbent position and prone in a standing position.
