Contradicitions about Torsades - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
Home
USMLE Articles
USMLE News
USMLE Polls
USMLE Books
USMLE Apps
Go Back   USMLE Forums > USMLE Step 1 Forum

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


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 01-17-2013
USMLE Forums Newbie
 
Steps History: ---
Posts: 2
Threads: 1
Thanked 0 Times in 0 Posts
Reputation: 10
EKG Contradicitions about Torsades

Can someone straight this out for me?

The definition of Torsades de Pointes (TdP), and managment, is contradictory.

Some references say its a tachycardia, others say its a bradyarrythmia.

All references say that prolonged QT (iatrogenic or genetic) predispose to development of Torsades, and further, that it may/will progress to Vfib.
The former suggests bradyarrythmia, and the latter tachyarrythmia.

Treatment is MgSO4 or Isoproterenol. This doesen`t help. (Other threatment not referred to here is of course drug discontinuation, and electrolyte restorance, esp Mg and K)

Rx Isoproterenol supports bradycardic nature of TdP, as it is a B1=B2 adrenergic agonist, it would increase HR (by decr APD) and bump it back UP to normal state.

Rx MgSO4 supports tachycardic nature as it is a relaxant that decreases SA node impulse formation and prolongs conduction time, and, it stabilizes excitable membranes (say, myocardium). This would suppress it DOWN to normal state.

Sidenote; Hypomagnesemia, can produce both tachy and brady arrythmias, but the latter is most common. right?

Thanks!!!
Reply With Quote Quick reply to this message



  #2  
Old 01-25-2013
USMLE Forums Addict
 
Steps History: Not yet
Posts: 138
Threads: 1
Thanked 46 Times in 26 Posts
Reputation: 56
Default

I'm pretty sure it's tachy
Reply With Quote Quick reply to this message
  #3  
Old 01-26-2013
USMLE Forums Newbie
 
Steps History: ---
Posts: 2
Threads: 1
Thanked 0 Times in 0 Posts
Reputation: 10
Default

So then why do you give isoproterenol, a B1=B2 agonist. (incr SANS)

I was pretty sure about torsades too..
Reply With Quote Quick reply to this message
 
  #4  
Old 01-26-2013
USMLE Forums Addict
 
Steps History: Not yet
Posts: 138
Threads: 1
Thanked 46 Times in 26 Posts
Reputation: 56
Default

I think Magnesium is first choice for torsades. Isoproterenol shortens QT, so maybe it could help controlling heart rate by helping a sinusal control of heartbeat or something... so that the ventricle doesn't go carazy on its own??
Reply With Quote Quick reply to this message
  #5  
Old 01-26-2013
billy's Avatar
USMLE Forums Guru
 
Steps History: Not yet
Posts: 444
Threads: 109
Thanked 369 Times in 208 Posts
Reputation: 379
Post

The QT interval is inverse to heart rate
Reply With Quote Quick reply to this message
  #6  
Old 01-27-2013
QueenDalya's Avatar
USMLE Forums Scout
 
Steps History: Not yet
Posts: 11
Threads: 2
Thanked 0 Times in 0 Posts
Reputation: 10
Default

hmmm probably to increase contractility
Reply With Quote Quick reply to this message



Reply

Tags
Cardiovascular-, EKGs-, Pathology-

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
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.

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.



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Torsades de pointes Dr. Mexito USMLE Step 1 Forum 1 01-05-2012 08:06 PM

RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2014)