Einthoven Triangle - USMLE Forums
 USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
 Home USMLE Articles USMLE News USMLE Polls USMLE Books USMLE Apps
 USMLE Forums Einthoven Triangle
 Register FAQs Members List Search Today's Posts Mark Forums Read

 USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam

#1
05-11-2015
 USMLE Forums Scout Steps History: Not yet Posts: 21 Threads: 12 Thanked 0 Times in 0 Posts Reputation: 10
Einthoven Triangle

Hi guys

I didn't understand anything in Einthoven's triangle and the basis of Axis Deviation

and what is this I + III = II ?

Any inputs are welcome :-)

#2
05-11-2015
 USMLE Forums Veteran Steps History: Step 1 Only Posts: 239 Threads: 4 Thanked 176 Times in 116 Posts Reputation: 188

Quote:
 Originally Posted by ubiquitous1987 Hi guys I didn't understand anything in Einthoven's triangle and the basis of Axis Deviation and what is this I + III = II ? Any inputs are welcome :-)

Even before you start reading I assume that you understand basic concepts on vectors,if so read on

Look at the pic, you will see

I: RA to LA
II: RA to LF
III: LA to LF

RA: right arm, LF: left foot

also mark the arrows that the I arrow is directed from RA to LA and so on...

By the rule of vectors in a triangle if we add all the three sides of the triangle in either clockwise or anticlockwise fashion they give us a total of zero,so

side1 + side2 + side3 = 0

but in this picture note II(side2) is not clockwise, its just the reverse ie for it to be clockwise it should had run from LF to RA instead it is RA to LF, so - II is same as clockwise, so we can write

side1 + side2 + side3 = 0

=> I + III + (-II) = 0
=> I + III = II

I hope its clear...and coming to axis deviation;try this site
Code:
`http://ecg.utah.edu/lesson/2-1`
although I dont know how much high yield axis deviation is

__________________
Hard work beats talent when talent doesn't work hard...
Step 1 Experience -
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- 259
#3
05-11-2015
 USMLE Forums Scout Steps History: 1+CK+CS Posts: 66 Threads: 0 Thanked 101 Times in 50 Posts Reputation: 111

I always use the quick and dirty method for determining axis that I learned from an anesthesia attending. Here's what you do:

1) Look at EKG
2) Put both of your fists in front of you and make two "thumbs up" signs
4) Look at the QRS complex in I and aVF on the EKG
5) Point your respective thumb in the direction of the respective QRS

Both thumbs up = normal axis
Left up/right down = left axis deviation
Right up/left down = Right axis deviation
Both down = lead misplacement, try again

This method is accurate ~95% of the time
 The above post was thanked by: CleverFOX (05-11-2015), MananaMD (05-11-2015), step123 (05-11-2015)

#4
05-11-2015
 USMLE Forums Scout Steps History: Not yet Posts: 76 Threads: 18 Thanked 39 Times in 26 Posts Reputation: 49

Quote:
 Originally Posted by Young Doc I always use the quick and dirty method for determining axis that I learned from an anesthesia attending. Here's what you do: 1) Look at EKG 2) Put both of your fists in front of you and make two "thumbs up" signs 3) Think of your left thumb as Lead I and your right thumb as aVF 4) Look at the QRS complex in I and aVF on the EKG 5) Point your respective thumb in the direction of the respective QRS Both thumbs up = normal axis Left up/right down = left axis deviation Right up/left down = Right axis deviation Both down = lead misplacement, try again This method is accurate ~95% of the time
Wow !
Impressive indeed !!!
A helpful trick I just discovered

Thank you !
__________________
If it doesn't challenge you, it doesn't change you...
#5
05-11-2015
 USMLE Forums Veteran Steps History: Step 1 Only Posts: 239 Threads: 4 Thanked 176 Times in 116 Posts Reputation: 188

Quote:
 Originally Posted by Young Doc I always use the quick and dirty method for determining axis that I learned from an anesthesia attending. Here's what you do: 1) Look at EKG 2) Put both of your fists in front of you and make two "thumbs up" signs 3) Think of your left thumb as Lead I and your right thumb as aVF 4) Look at the QRS complex in I and aVF on the EKG 5) Point your respective thumb in the direction of the respective QRS Both thumbs up = normal axis Left up/right down = left axis deviation Right up/left down = Right axis deviation Both down = lead misplacement, try again This method is accurate ~95% of the time
Hey it actually worked thanks a bunch...bookmarked this now,anyone can try the following:

BOTH UP in this one:

LEFT UP, Right Down in this one:

RIGHT UP, Left Down in this one:

I just tried your technique on this and it worked just fine thanks a lot
__________________
Hard work beats talent when talent doesn't work hard...
Step 1 Experience -
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- 259
 The above post was thanked by: step123 (05-11-2015)

Message:
Options

## Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
User Name:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
 AMG IMG ---
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

 Not yet Step 1 Only CK Only CS Only 1 + CK 1 + CS 1+CK+CS CK+CS 1+CK+CS+3 ---
Favorite USMLE Books
 What USMLE books you really think are useful. Leave blank if you don't want to tell.
Location
 Where you live. Leave blank if you don't want to tell.

## Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.