INOCA means the heart is not getting enough blood or oxygen, even though the main heart arteries are not blocked. This condition is common and can be treated. Common symptoms include chest pain, pressure, shortness of breath, fatigue, and symptoms with stress or exercise, or at rest.
Conditions that fall under INOCA include:
- Coronary microvascular dysfunction (CMD). With this condition, the tiny blood vessels in the heart do not work the way they should. These vessels may not open enough to let blood flow and symptoms can feel just like a heart attack. The condition may not be picked up by routine cardiac tests. PET myocardial perfusion imaging or invasive coronary function testing can be performed to look at these small vessels.
- Coronary vasospasm. Vasospasm happens when a heart blood vessel suddenly tightens or squeezes. This can reduce blood flow for a short time and may cause chest pain at rest, while sleeping, during exertion, or without any clear trigger. Stress, cold, or certain medications are common triggers in some people Because the artery looks normal most of the time during testing, this condition is often missed unless specific testing, called coronary function testing is performed.
- Myocardial bridging. With this condition, a heart blood vessel runs through the heart muscle instead of on top of it. When the heart squeezes, the artery can be squeezed as well and may limit blood flow, especially during activity. Many people never know they have it unless they develop symptoms. Advanced imaging including CT scans and invasive coronary function testing are performed to see if a myocardial bridge is causing symptoms.
