Acute and Chronic Complications of Myocardial Infarction

Introduction

Myocardial Infarction is necrosis of the cardiac muscle that is caused by ischemia. The most common underlying cause is atherosclerosis. Complications can be grouped by the timing of said complications as acute and sub-acute-chronic.

Acute Complications

Acute complications manifest within hours to days. These manifestations include:

1. Cardiogenic Shock due to Left Ventricle Failure - this manifests one day after STEMI and a few days after NSTEMI. It can present as volume overload, sustained hypotension and heart failure signs.
2. Arrhythmia - manifests days after and can be a tachyarrhythmia or bradyarrhythmia. Regarding tachyarrhythmia it can be further subdivided into Supraventricular and ventricular tachyarrhythmia. In supraventricular arrhythmia the most common is atrial fibrillation. In Ventricular tachyarrhythmia this can be accelerated idioventricular rhythm.
3. Ischemic papillary muscle rupture - this manifests in a week and can present as a systolic murmur on an echocardiogram
4. Ventricular Septal Defect - this manifests within a week and presents as a holosystolic murmur and thrill on echocardiography.
5. Left ventricular free wall rupture - this manifests in a week and manifests as acute decompensation in relation to cardiac tamponade which presents as hypotension, increased jugular venous pressure and diminished heart sounds.
6. Early Pericarditis - manifests within days and presents as a pericardial friction rub in majority of patients

Sub-acute-chronic Complications

These complications arise much later after MI.

1. Left Ventricular Thrombus - manifests in two weeks
2. Left Ventricular Aneurysm - manifests days to weeks and can present as diffuse and displaced point of maximal impulse and can include heart sounds S3 and s4. On electrocardiogram Q waves with repeated ST elevation on V1-V3 can be seen.
3. Late Pericarditis - this develops in weeks to months after MI and can present as pericardial friction rub and fever.

Sources

University of California San Francisco. “06. Complications of Acute Myocardial Infarction,” UCSF Hospitalist Handbook, https://hospitalhandbook.ucsf.edu/06-complications-acute-myocardial-infarction/06-complications-acute-myocardial-infarction (accessed December 19, 2025)

Kumar, V., Abbas, A. K., & Aster, J. C. (Eds.). (2018). Robbins basic pathology (10th ed.). Elsevier.