Myocardial scars remain forever ! It forms the focus for many chronic ventricular tachycardias following MI. A healed scar is not often benign . It blocks the electrical wavelets and deflects into multiple directions some of them may reenter and form re-entrant VT .
This scar fascinated one man from Holland -De Bakker . . . his quest for myocardial scars produced this excellent paper .
No one can do such a meticulous work today !
He did a extraordinary study with the scarred papillary muscle of infarcted myocardium . It included stunning histo-pathological analysis .He found for the first time , how the scar even though mechanically idle conducts in multiple directions that precipitate the arrhythmias
We need to classify myocardial scar for understanding better the VT circuits. The newer imaging like Carto system can help us in imaging the ventricular scars.
A rough approach for myocardial scar classification could be .
Location
- Epicardial
- Endocardial
- Transmural
Combined
- Predominantly endocardial
- Predominately epicardial
Septal scars
Anterior
Apical
Posterior scars
*With or with out Pap Muscle
Based on thickness and volume**
Small< 2CC >5CC
Intermediate up to 10cc
Large >20cc
**Scar volume
Based on electro-physiological properties
- Inert
- Inducible
- Spontaneous with clinical VT
Based on Metabolic activity
PET matched
Mismatched
Scars with reference to vascularity
- Vascularised scars
- Avascular scars
- Revascularised scars
Further modification of the scheme by the readers are welcome
Clinical implication of scars apart from arrhythmias ?
CRT lead positioning
Dr.S.Venkatesan MD 