Myocardial stunning in hypertrophic cardiomyopathy with normal coronary arteries

Area of Science:

• Cardiology
• Cardiovascular Physiology

Background:

• Obstructive hypertrophic cardiomyopathy (HCM) is a condition characterized by thickening of the heart muscle, potentially leading to dynamic left ventricular outflow tract obstruction.
• Myocardial ischemia, a state of reduced blood flow to the heart muscle, can occur in various cardiac conditions.

Observation:

• A patient diagnosed with obstructive hypertrophic cardiomyopathy presented with symptoms of myocardial ischemia.
• Diagnostic evaluation revealed normal epicardial coronary arteries, ruling out obstructive coronary artery disease as the cause of ischemia.
• The patient experienced transitory apical akinesia, a form of regional wall motion abnormality where the apex of the heart fails to contract normally.

Findings:

• The myocardial ischemia was accompanied by transient apical akinesia.
• Crucially, the observed wall motion dysfunction, specifically apical akinesia, persisted for several hours even after the relief of myocardial ischemia.
• This suggests a potential disconnect between the resolution of ischemic symptoms and the recovery of regional myocardial function in this specific context.

Implications:

• This case highlights a potential mechanism of myocardial ischemia in obstructive hypertrophic cardiomyopathy beyond epicardial coronary artery disease.
• The persistent apical akinesia despite ischemia relief warrants further investigation into the underlying pathophysiology, possibly involving microvascular dysfunction or altered myocardial energetics in HCM.
• Understanding these mechanisms is crucial for optimizing the management and risk stratification of patients with obstructive hypertrophic cardiomyopathy.