Tension Headache: Given the stress and anxiety that can follow a myocardial infarction (MI), tension headaches are a common complaint. The physical and emotional strain of dealing with a significant cardiac event can lead to muscle tension, which in turn causes headaches.

Hypertension: Patients with a history of MI often have hypertension, which can cause headaches due to elevated blood pressure. Uncontrolled hypertension is a risk factor for both MI and headaches.
Medication Side Effects: Various medications used post-MI, such as beta-blockers, ACE inhibitors, or statins, can have side effects that include headaches.
Anxiety or Depression: The psychological impact of an MI can lead to anxiety or depression, both of which are associated with headaches.

Subarachnoid Hemorrhage: Although less likely, a sudden, severe headache (often described as "the worst headache of my life") could indicate a subarachnoid hemorrhage, which is a medical emergency. The stress of an MI might increase the risk of aneurysm rupture.
Temporal Arteritis: This condition, more common in older adults, can cause headaches and is associated with polymyalgia rheumatica. Missing this diagnosis could lead to blindness if not treated promptly with corticosteroids.
Pituitary Apoplexy: A rare but potentially life-threatening condition that could cause a sudden headache, often accompanied by visual disturbances and acute hormonal deficiencies.

Cervicogenic Headache: Caused by referred pain from the cervical spine, these headaches can occur in patients with a history of neck strain or injury, which might be secondary to the physical exertion or stress associated with an MI.
Thunderclap Headache: A very severe headache that reaches its maximum intensity within a minute, often indicative of a subarachnoid hemorrhage but can have other rare causes.
Headache Associated with Cardiac Conditions: Certain cardiac conditions, such as coronary artery dissection or cardiac cephalalgia, can cause headaches, although these are exceedingly rare.