Post-MI Ventricular Septal Rupture

Four days after an MI, a patient who suddenly develops dyspnea and hypotension is not simply having more left-ventricular failure. A new harsh systolic murmur, especially at the lower left sternal border, raises concern that infarcted septal muscle has torn. Blood now escapes from the left ventricle into the right ventricle during systole; pulmonary blood flow rises while effective systemic output falls. The patient can deteriorate rapidly from a new murmur to pulmonary edema and cardiogenic shock. This is ventricular septal rupture (VSR), a post-infarction mechanical emergency. The timing is a clue, not a rule: VSR most often appears 2–8 days after infarction, with an early peak within 24 hours and a second peak around days 3–5. A quiet or absent murmur does not reassure when shock is advanced because the left-to-right pressure gradient may have fallen. Any post-MI patient with a new systolic murmur, recurrent chest pain, or heart failure out of proportion to the expected course needs urgent echocardiography. The murmur starts the work-up; the blood pressure and perfusion pattern determine how stabilization is performed.