If QRS complex is positive in leads II
and a VF and a negative in lead III, the mean electrical axis (MEA) is between:
A. – 30o and 0o
B. 0o and +30o
C. +30o and + 60o
D. +60o and +90o
Answer.
B. 0o and +30o
If the QRS complex is positive in lead
II, the MEA must be between 30° and +150°. If the QRS complex is positive in a
VF the MEA must be between 0° and 180°. If the QRS complex is negative in lead
III, the MEA must be between —150° and +30°. For all three conditions to exist,
the MEA must be between 0° and +30°.
