Emirates do their own medical insurance which is one of the reasons the employment medical is so strict. If you have any further problems down the line with your heart you may well find the Emirates "insurance" doesn't cover you and medical care in Dubai is extremely expensive. With any kind of pre-existing condition I'd think very, very carefully about the Middle East. A class one EASA medical means nothing here and even IF you pass the pre-employment medical every renewal will be a lottery depending on which doctor you get - if you win you get another year of flying, if you loose you loose your career. Do you feel lucky?