Yes, there are quiet a few companies that will offer cover for medical conditions including those who have had heart attacks.
Whether they will offer you a policy that includes cover for your existing medical conditions (and how much it may cost) will depend on a number of factors, including how recently you suffered a heart attack and how well you have recovered (taking into account such things as recovery, medication, and lifestyle), the type of policy you are looking to purchase and where you are going.
Make sure that what ever policy you go with that you declare all your conditions and understand what they will and won't cover. Some companies will not offer any cover relating to your known medical conditions and any future condition that could be attributed to a pre-existing condition.