Non infarction Q waves Precise guide for Allied Health Science Students especially cardiac specialty students, DGNM, B.Sc Nursing & M.Sc Nursing Students regarding Non Infarction Q waves

1. NON INFARCTION Q
WAVE
Mr. Aby Thankachan,M.Sc(N), Ph.D
Asst Professor
HICON, CBE

2. Q WAVE
The Q wave is the first downward
deflection after the P wave and the first
element in the QRS complex.
When the first deflection of the QRS
complex is upright, then no Q wave is
present. The normal individual will have
a small Q wave in many, but not all,
ECG leads.

3. Abnormalities of the Q waves are mostly indicative
of myocardial infarction.
The terms “Q wave myocardial infarction” and “non-
Q wave myocardial infarction” are earlier
designations of different types of MIs ultimately
resulting in, respectively, Q wave development or
the absence of Q wave development.
Loss of electromotive force associated with
myocardial necrosis contributes to R wave loss
and Q wave formation in MI.

4. This mechanism of Q wave pathogenesis, however,
is not specific for coronary artery disease with
infarction.
Any process, acute or chronic, that causes sufficient
loss of regional electromotive potential can result in
Q waves.
For example, replacement of myocardial tissue by
electrically inert material such as amyloid (abnormal
fibrous, extracellular, proteinaceous deposits found
in organs and tissues)or tumor can cause Non
infarction Q waves

5. A variety of cardiomyopathies associated with
extensive myocardial fibrosis can cause
pseudoinfarction patterns.
Ventricular hypertrophy also can contribute to the
appearance of Q waves.
Q waves simulating the ECG pattern of coronary artery
disease can be related to one (or a combination) of the
following four factors
(1)physiologic or positional variants,
(2)altered ventricular conduction,
(3)ventricular enlargement, and
(4)myocardial damage or replacement.

6. Prominent Q waves can be associated with a variety
of positional factors that alter the orientation of the
heart .
Depending on the electrical axis, prominent Q waves (as
part of QS- or QR-type complexes) can appear in the limb
leads (aVL with a vertical axis and III and aVF with a
horizontal axis).
The axis of the ECG is the major direction of the overall
electrical activity of the heart. It can be normal, leftward
(left axis deviation, or LAD), rightward (right axis deviation,
or RAD) or indeterminate (northwest axis).

7. An intrinsic change in the sequence of
ventricular depolarization can lead to pathologic,
noninfarct Q waves.
The two most important conduction
disturbances associated with pseudoinfarction Q
waves are LBBB and the Wolff-Parkinson-White
(WPW) preexcitation patterns.
Wolff-Parkinson-White syndrome in which an extra
electrical pathway in the heart causes a rapid heartbeat.