10/01/2026
Hypotension in Inferior Wall Myocardial Infarction
Cause
Inferior wall myocardial infarction is most commonly caused by right coronary artery (RCA) occlusion. When the RCA is involved, the right ventricle is frequently affected.
Reasons for hypotension
• Right ventricular infarction leads to impaired right ventricular filling, reduced preload to the left ventricle, and a fall in cardiac output.
• Activation of the vagal (Bezold–Jarisch) reflex results in hypotension associated with bradycardia.
• Ischemia of the sinus node or atrioventricular node, which are supplied by the RCA, causes bradycardia or heart block, leading to reduced cardiac output.
Clinical clues
• Hypotension with clear lung fields
• Bradycardia or atrioventricular block
• Inferior wall STEMI on ECG involving leads II, III, and aVF
• Suspicion of right ventricular infarction, confirmed with right-sided ECG leads, especially V4R
First-line treatment
Intravenous normal saline for volume expansion restores preload and improves cardiac output in right ventricular infarction.
Important note
Nitrates and diuretics should be avoided in hypotensive inferior or right ventricular myocardial infarction, as they further reduce preload and worsen hypotension.