Reasons Why Not To Use Lead II

I would like to show you some very good reasons why not to monitor a patient in lead II. We monitor patients for rhythm changes and disturbances, look at the following examples and then you can be the judge....All examples are recorded in LEAD II and MCL1 simultaneously showing the same complex in spatial time...What you will notice is that LEAD II does not look much different in the four examples, they are all wide and negative in deflection but MCL1 gives us more information...

In 1991 a study was done in San Francisco evaluating the diagnostic yield from leads V1, V6, MCL1 and MCL6 compared to Lead 2. Using Lead 2 the diagnosis was correctly made in only 34% of wide QRS tachycardias. However a correct diagnosis was achieved in 75 to 80% with each of the precordial leads.

Example of Right Bundle Branch Block

Example of Left Bundle Branch Block

Example of Right Ventricular PVC

Example of Left Ventricular PVC

Ekg Clues of Ventricular Tachycardia

1. Morphology:
A. Globally unlike either BBB (Marriott)
B. V Leads: None with RS complex/ Any RS > 0.10s (Brugada :1991)
C. Single Lead: V1 - qR or R with Lt Rabbitt Ear (Gozensky/Thorne : 1974)
Single Peak (known as steeple)(Wellens/Brugada : 1987)
QR or Equiphasic RS
Fat R, slurred downstroke to late nadir(tip) >.06s(1.5 baby blocks)
V6 - rS, equiphasic QS or QR complex
S or QS > 15mm deep

2. Polarity
A. Axis in no mans land : Neg Complex I, AVF, or I, II, III
Concordance positive or negative of chest leads V1 - V6 ( exceptions *** wpw can produce Pos concordance/ LBBB with LAD may produce Neg concordance)

Now you can see why it is so important to monitor a critical patient in a lead that will give you more information. If you have the capability to monitor more than just one lead that is all the better, however if you can only monitor one lead at a time, MCL1 is the preferred lead due to the amount of information you can obtain.