What is a vector ECG?

“Because the movement of charge (i.e., the spreading wave of electrical activity in the heart) has both a three-dimensional direction and a magnitude, the signal measured on an ECG is a vector.

How many leads are used in Vectorcardiography?

The modern VCG system employs a set of three orthogonal leads, one in the right to left direction (x lead), one in the head to foot direction (y lead), and one in the front to back direction (z lead).

What is a normal QRS T angle?

QRS-T angle 0 to 90°, QRS-axis -30 to 90°, and T-wave axis 0 to 90° were considered normal.

What is normal ECG?

Normal intervals Normal range 120 – 200 ms (3 – 5 small squares on ECG paper). QRS duration (measured from first deflection of QRS complex to end of QRS complex at isoelectric line). Normal range up to 120 ms (3 small squares on ECG paper).

Why is Q wave downward?

The rule is: if the wave immediately after the P wave is an upward deflection, it is an R wave; if it is a downward deflection, it is a Q wave: small Q waves correspond to depolarization of the interventricular septum. Q waves can also relate to breathing and are generally small and thin.

How many loops does the heart Vector make during the cardiac cycle?

A heart cycle is represented by three loops corresponding to P, QRS, and T wave activities [5] . Decrease in clinical interest for VCG motivated researchers to transform 3-lead VCG into the 12-lead ECG, such as Dower transform [6], enables 12-lead ECG diagnosis to those who possessed VCG equipment [7]. …

What is the theory of einthoven?

Einthoven’s triangle is an imaginary formation of three limb leads in a triangle used in electrocardiography, formed by the two shoulders and the pubis. The shape forms an inverted equilateral triangle with the heart at the center. It is named after Willem Einthoven, who theorized its existence.

What is the normal QT interval on an ECG?

Regarding the 12-lead ECG, “normal” QTc values are generally considered to be between 350 and 440 ms,18,23 but, as will be discussed in the next section, this consideration of QTc >440 ms as indicative of “borderline QT prolongation” has probably been responsible for the greatest number of premature LQTS diagnostic …

Is Sinus a rhythm?

Sinus rhythm is the name given to the normal rhythm of the heart where electrical stimuli are initiated in the SA node, and are then conducted through the AV node and bundle of His, bundle branches and Purkinje fibres. Depolarisation and repolarisation of the atria and ventricles show up as 3 distinct waves on ECG.

What happens when ECG is abnormal?

An abnormal ECG can mean many things. Sometimes an ECG abnormality is a normal variation of a heart’s rhythm, which does not affect your health. Other times, an abnormal ECG can signal a medical emergency, such as a myocardial infarction /heart attack or a dangerous arrhythmia.