Mental stress-induced myocardial ischemia

Mental stress-induced myocardial ischemia (MSIMI) is a medical condition in which acute psychological stress can trigger a transient myocardial ischemia, which is a state of reduced blood flow to the heart muscle, often without the presence of significant coronary artery disease (CAD). It is distinct from conventional stress ischemia caused by physical exertion or pharmacological agents. MSIMI is often silent and detected through specific cardiac function tests during mental stress challenges.

Mechanism
Mental stress triggers various physiological changes in the body, activating mechanisms such as the autonomic nervous system (ANS) and the hypothalamic–pituitary–adrenal axis (HPA), resulting in hemodynamic, neuroendocrine, and immune responses. Typically, these responses are adaptive and help individuals cope with environmental changes, referred to as the "defense response," which prepares them for fight or flight. Consequently, the risk of cardiovascular (CV) events resulting from mental stress is influenced by external factors and an individual's stress threshold, which is shaped by genetic predispositions and life experiences. This variability explains why people respond differently to stressors.

Mental stress-induced myocardial ischemia involves abnormal microvascular vasoreactivity and inflammation, with increased brain activity in regions that modulate autonomic nervous system reactivity to emotional stress, fear. Emotional responses and certain psychological traits may influence the occurrence of MSIMI. MSIMI can occur at lower cardiac workloads, independent of hemodynamic changes, and is not directly related to the severity of angiographic CHD. It can occur in patients with normal cardiac stress testing and can often be silent.

Clinical significance
MSIMI is associated with a twofold increased risk of major adverse cardiovascular events (MACE) compared to those without MSIMI. It is particularly prevalent among young women with myocardial infarction (MI) and those with psychological comorbidities.

Studies have found that young women who have had a myocardial infarction are twice as likely to develop mental stress-induced myocardial ischemia (MSIMI) compared to men of similar age.

Diagnostics
Various techniques like electrocardiogram (ECG), echocardiography, and positron emission tomography (PET) are used to assess MSIMI. The incidence of MSIMI has varied across studies due to different assessment methods and mental stressors.

Treatment
Current research focuses on understanding stress pathways in CAD and integrating mental health, behavioral medicine with routine cardiology care to improve patient outcomes.

Epidemiology
Approximately 30% of CAD patients experience MSIMI under mental stress, which typically is silent and not related to the severity of CAD.