It is the most common method for diagnosing of cardiovascular diseases. This technique is based on the recording of electrical potentials of the heart muscle, including the duration and timing of each heartbeat electrical phase. If any part of the heart muscle experiences lack of oxygen, the electric activity of this part changes and that is immediately reflected on the electrocardiogram. ECG requires 12 electrodes to be set on the patient’s body.
This method is harmless and does not cause any discomfort in patients. The complete procedure lasts for about 10 minutes. The results help detect arrhythmias, cardiac conduction disorders (asequences), signs of coronary blood flow disorder, scarring of heart tissue, as well as hypertrophy or enlargement of different heart compartments, and myocardial ischemia if it takes place during the procedure.
However, this method has some limitations. For example, if a patient suffers from angina and the procedure is conducted outside the attack, then the result may show no pathological changes; the same is true for the transient rhythm and conduction disturbances. In such cases, it is necessary for the patient to have records of his or hers heart electrical activity during the day, and this method is called Holter Monitoring.
This method involves long-term recording (during 12, 24, 48 hours or even longer) of the patient’s ECG with the help of a portable device (electrocardiograph) called a Holter monitor. Traditional electrocardiography requires the patient be at rest.
During Holter monitoring, the patient wears the device all day long while participating in various physical activities. During the day, patients note in a monitor diary, their physical activities, emotional stress, painful sensations and drug intake times.
Many cardiovascular diseases become apparent under different circumstances, such as physical activity, stressful situations, and while eating or sleeping, which is why round the clock monitoring of the heart is desirable.
In some cases, patient may experience arrhythmias that occur only at certain times of the day; something that a traditional ECG would not detect.
Moreover, it is essential to identify the type of these arrhythmias, their duration, form, when they appear and whether they are accompanied by any symptoms.
Also, this method can be applied to assess the effectiveness of antiarrhythmic drugs and functioning of the artificial pacemaker.