Introduction - ECG Acquisition and Automated Remote Processing - page 3

Legends:

Deoxygenated blood
Oxygenated blood flow
Valve

flow

Tricuspid
valve

Pulmonary artery

Right Atrium

Right Ventricle Lungs

Pulmonary
valve

Pulmonary Vein

Inferior vena cava

Superior vena cava

Aorta

Whole body Left Ventricle

Left Atrium

Aortic
valve

Mitral
valve

Fig. 1.2 Schematic blood flow direction between heart chambers

delivered blood is divided into major arteries which supply them to the lower and
upper parts of the body to feed each body cell. The pumping action of the heart
supports the following circulatory systems:

Pulmonary circulation: This supports blood circulation to the lungs for

purification.
Systemic circulation: This supports blood circulation to the entire body except the
lungs.
Coronary circulation: To function properly, the heart cells need oxygenated blood.
Coronary circulation takes care of this.

A healthy adult human heart contracts (or expands) 72-80 times per minute.
Since the pumping action required for systemic circulation is much greater than
pulmonary circulation, the left atrium and left ventricle are more muscular than
right counterparts.

1.3 Genesis of the Electrocardiogram

The mechanical action of the heart is due to generation of small electrical impulses
and their propagation on the heart surface. ECG represents time-averaged repre-
sentation of these electrical potentials picked up by placing electrodes on body
surface. As a convention, an activity is recorded as positive (negative) when the
resulting electrical impulses move toward (away from) the electrode.