When is this exam indicated?
The electrocardiogram allows the cardiologist to detect:
- Presence of cardiac arrhythmias;
- Ischemia or myocardial infarction, presumably secondary to a narrowing or complete occlusion of the coronary arteries of the heart;
- Presence of structural alterations of the cardiac cavities, atria, and/or ventricles. Structural alterations of the cardiac cavities include conditions such as: dilated cardiomyopathy, hypertrophic cardiomyopathy, left ventricular hypertrophy, and enlarged heart. In such cases, the walls of the atria and/or ventricles may thicken or stretch;
- Consequences of a previous heart attack;
- Presence of cardiac conditions, characterized by altered electrical conduction. Some examples of these cardiac conditions are: long QT syndrome and bundle branch blocks (right or left).
In addition, the electrocardiogram allows to evaluate:
- The function of pacemakers and similar devices (such as the implantable cardioverter defibrillator), for individuals who are obviously carriers;
- The effects on the heart of those drugs that could alter, under certain circumstances, the frequency or electrical conduction of the heart.
How is it performed?
Generally, the electrocardiogram does not require any special preparation.
However, it should be noted that patients undergoing pharmacological treatment or carrying a pacemaker (or similar instruments) must inform the cardiologist of their condition. It is performed by applying 10 electrodes (metal plates, applied to the skin by means of an adhesive layer).