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
Sir, I have type 3 LAD. Can you say me the details about it. I have high blood pressure since 26 years old. Now I am 47. Recent angiogram shows that I have minor cad with moderate calibre in diagonal one and OM 1. Ostial disease. LCX dominant.Rca non dominant.Blood pressure and medication is going on for last 20 years. Cholesterol medicine is started now. I felt severe pain on left side of my chest when cycling or walk in speed for a long time. Diastolic dysfunction of grade one and trivial tricuspid regargitation has been evolved. Have you any suggestions for me.I am a teacher of a primary school.
Your records suggest minimal CAD and has little significance.Follow your cardiologsts advice