Hello! Thank you for asking on HCM! I understand your concern, and would like to explain that the answer to your question depends on whether your father has experienced a myocardial infarction, or an unstable angina (both are clinical presentations of a heart attack). When a myocardial infarction has happened, it is important to closely monitor the patient for possible arrhythmic event (sometimes dangerous and life-threatening), irrespective of a successful coronary revascularisation. When only unstable angina was present, then after successful revascularisation, there is no need for any special medical monitoring. You should discuss wit attending physician about the severity of his heart attack and possible clinical implications. Nevertheless, after a couple of days the risks mostly fade and nothing to worry about. After a couple of days from hospital discharge, your father is able to travel, keeping in mind not to strain to much and be alert about any suspicious clinical signs (in that case to consult immediately his doctor). Hope to have been helpful to you. Greetings! Dr. Iliri