13. General Information About the Heart and ECG Measurements
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About the ECG Waveform
The ECG waveform shows the rhythm of your heartbeat during the 30-second
measurement and displays the electrical activity causing the heart to beat. The
waveform for each heartbeat shows the progress of the electrical impulse across
and through the heart.
The first peak indicates the spread of the impulse over the atria and the beginning
of their contraction. This is known as the P wave. The second peak indicates the
spread of the impulse over the ventricles and the beginning of their contraction.
This is known as the QRS complex. The third peak indicates the activity as the
heart relaxes (re-polarization), and is known as the T wave.
What is Arrhythmia?
Arrhythmia is a condition where the heartbeat rhythm is abnormal due to flaws in
the bio-electrical system that drives the heartbeat. Typical symptoms are skipped
heartbeats, premature contraction, an abnormally rapid (tachycardia) or slow
(bradycardia) pulse. This can be caused by heart disease, ageing, physical
predisposition, stress, lack of sleep, fatigue etc.
Arrhythmia can only be diagnosed by a doctor through a special examination.
What is Ischemia?
Ischemia is a condition in which insufficient oxygen is supplied to parts of the heart
or other parts of the body. This is usually due to a blockage or partial blockage of
an artery.
Ischemia can only be diagnosed by a doctor through a special examination.
Ventrcular contraction
(QRS complex)
Re-polarization (T wave)
Atrial contraction (P wave)
HCG801-C1.fm Page 56 Wednesday, September 27, 2006 9:48 PM
