The electrical activity of the heart can be recorded using surface electrodes on the surface of the body. This tracking of electrical signals is called an electrocardiogram, or ECG, for short. An ECG is performed on a bed and involves placing ten electrodes on the body. This results in the “12 leads” appearing on the electrocardiogram (three additional electrodes are mathematically calculated, and one is ground).[75]
There are five distinct features on the electrocardiogram: positive P (atrial depolarization), and QRS complex (ventricular depolarization). Depolarization of the ventricles occurs at the same time, but cannot be sufficiently visible on the chart.[75]), and T wave (repolarization of the ventricles).[9] When heart cells contract, they create a current that travels through the heart. A downward skew in the diagram means that the cells become more positively charged (“depolarization”) in the direction of that electrode, while an upward skew means that the cells become more positively charged (“repolarization”) in the direction of that electrode, depending on This is on the pole position, so if a wave of depolarization moves from left to right, the pole on the left will show a negative deviation, and the pole on the right will show a positive deviation. The ECG is a useful tool for detecting arrhythmias and for detecting insufficient blood supply to the heart.[75] Sometimes abnormalities are suspected, and their presence on the electrocardiogram is not confirmed immediately. The test can be used when exercising to elicit an abnormality, and EKG electrodes can also be worn for a much longer period of 24 hours eg as a Holter monitor if there is a rhythmic abnormality not present at the moment of assessment.
