What is upward deflection in ECG?

What is upward deflection in ECG?

A positive (upward) deflection appears in any lead if the wave of depolarization spreads toward the positive pole of that lead. Thus, if the path of atrial stimulation is directed downward and to the patient’s left, toward the positive pole of lead II, a positive (upward) P wave is seen in lead II (Figs. 4-2 and 4-3).

What is the vector theory of ECG formation?

They are all based on the idea that each of the ECG waves (P, QRS and T waves) can be understood as a three-dimensional electric vector that moves in space and time. It is usually assumed that the electric vector loop traces the instantaneous position of the electric wave, as it spreads through the heart muscle.

How do you interpret a normal ECG?

How to Interpret an ECG in Seven Steps

1. Step 1: Heart Rate.
2. Step 2: Heart Rhythm.
3. Step 3: Electrical Heart Axis.
4. Step 4: The PR Interval.
5. Step 5: The QRS Complex.
6. Step 6: Repolarization.
7. Step 7: The R/S Ratio.
8. How to Interpret an ECG: An Overview.

What causes a positive deflection on ECG?

Axis refers to the direction of the main vector in which depolarization occurs. A wave that travels toward a positive lead will result in an upward or positive deflection (tracing) on the ECG, and a wave traveling away from a positive lead will result in a downward or negative deflection.

What causes upward deflection in ECG?

The basic pattern of the ECG is logical: electrical activity towards a lead causes an upward deflection. electrical activity away from a lead causes a downward deflection. depolarization and repolarization deflections occur in opposite directions.

What is the normal ECG pattern?

The Normal ECG A normal ECG contains waves, intervals, segments and one complex, as defined below. Wave: A positive or negative deflection from baseline that indicates a specific electrical event. The waves on an ECG include the P wave, Q wave, R wave, S wave, T wave and U wave.

What is the mean P vector?

“p-vector” means “vector of length p”. Since input variables (X) can be vectors, “p-vector” used in this text to refer to that case; so “p” represents number of elements in an input vector.

What is the cardiac vector?

If a snapshot of electrical activity could be taken at a given instant during the process of depolarization, many individual waves of depolarization represented by arrows could be observed (black arrows in figure). Each arrow represents a different individual vector representing depolarization.

Why the T wave is a positive upward deflection?

T and U waves The T wave represents ventricular repolarization. Generally, the T wave exhibits a positive deflection. The reason for this is that the last cells to depolarize in the ventricles are the first to repolarize.

What does a flat T wave mean on an ECG?

Flattened T waves are a non-specific finding, but may represent. Ischaemia (if dynamic or in contiguous leads) or. Electrolyte abnormality, e.g. hypokalaemia (if generalised)