Cardiac arrhythmias

Cardiac arrhythmias, especially ventricular ones, are a mechanism associated with sudden natural death.

General

Associations

• Myocardial infarction.
• Hypertensive heart disease.
• Commotio cordis.
• Arrhythmogenic right ventricular cardiomyopathy.

Non-cardiac

• Electrocution.
• Hyperthermia.

Microscopic

Features - associated with ventricular fibrillation:

• Myofiber break-up (MFB) - key feature.
  • Fractures of the sarcomeres perpendicular to the long axis.
  • Associated with square nuclei.

Notes:

• In cases with malignant arrhythmias, as shown by cardiac monitor at the time of death, MFB is seen in multiple sections.
• MFB seems to be predominantly mid-myocardial/epicardial, with relative sparing of the subendocardium.^{[citation needed]}