Lagan is having heart problems. He currently has some heart beat abnormalities.
It is possible that it is the beginning of common heart problems seen in Irish Wolfhounds. According to one study that I read, about 40% of Irish Wolfhounds die of heart problems or complications from having a heart problem. Usually these problems turn up around age 6 (Lagan just turned 6 in January) and are more common in males. Often, these problem initially present with Atrial Fibrillation and then become Dilated Cardiomyopathy.
Our vet is giving us a referral to the Cardiology Dept at the NC State Vet School. There are lots of medication out there for heart problems. The hope is that a more detailed analysis of what his specific heart condition is will provide a clearer picture of his current heart problem and consequently what is the best way to treat it right now.
For more information:
The Prevalence of Cardiomyopathy in the Irish Wolfhound - Journal of American Animal Hospital Association
About general health problems in Irish Wolfhounds:
The Irish Wolfhound Foundation
Results of research in the health of Irish Wolfhounds presented by the (British) Kennel Club: