LAD is graded into three types according to
Type 1 : Falls short of Apex
Type 2 : Reach up to the LV apex
Type 3 : Wraps around LV apex and travels some distance in the posterior Inter-ventricular groove.
Clinical Importance of Wrap around LAD
As the name implies , LAD should descend only in anterior aspect in about 15 % population it can take a posterior descending course as well .
When LAD wants to conquer more areas of heart is it a clinical advantage ?
When LAD wraps around the LV apex, anterior MI due to LAD occlusions can show changes in inferior leads. (Antero Inferior MI )
In ideal anatomic /Physiologic conditions LAD should nearly meet the PDA to prevent any water shed area.
There is usually a trade off between the terminal LAD and length of PDA ( whether it arises from LCX or RCA.)
There is some evidence to suggest the site of ventricular rupture in anterior MI is related to the gap in the LAD/PDA drainage zones.
Patients with Type 1 LAD are at risk of LV apical ischemia if the dominant LCX /RCA is not supportive .
Final message
A long LAD is definitely a hemo-dynamic advantage in physiology , Of course it goes without saying . . . when it’s likely to get obstructed it is always better to have a Type 1 !
Dr.S.Venkatesan MD 
Hi Dr Venkatesan, I am currently chasing data on the population with ‘wrap around’ LAD’s for a small research project. Would you have any information pertaining to the percentage of the population with this variant (Type III).
Thank you kindly,
E.McDonald
Hi
I am also just looking at our data.
I will report once the collection is complete .
But one thing is sure it is more prevalent than we would thinK.
venkatesan
Isn’t type 4 a better term for wraparound lad?
Hi Mr Vijay
Thanks for your comments
We can do a study .
Call me 9840059947 or write to me
drvenkatesans@yahoo.co.in
Thanks
Sorry this comment meant for some one else