Electrocardiogram (ECG or EKG)

Electrocardiograms (ECG or EKG), are a noninvasive test crucial for revealing underlying heart conditions by gauging the heart’s electrical activity. By strategically placing electrical sensing devices on the body, healthcare professionals can decipher valuable information about various heart conditions through characteristic patterns on the EKG.

Measuring Heart Activity

An Electrocardiogram (ECG) measures the heart’s underlying rate and rhythm, its orientation in the chest cavity, potential hypertrophy (increased thickness) of the heart muscle, signs of damage to different parts of the heart, indications of impaired blood flow to the heart muscle, and patterns of abnormal electrical activity that may predispose patients to cardiac rhythm disturbances. This diagnostic tool proves invaluable in identifying a range of heart problems.

Diagnosing Heart Conditions

Electrocardiograms can diagnose conditions such as abnormally fast or irregular heart rhythms, abnormally slow heart rhythms, irregular conduction of cardiac impulses, evidence of prior or acute heart attacks, and adverse effects on the heart from various diseases or systemic conditions. It is also instrumental in detecting congenital heart abnormalities, abnormalities in blood electrolytes, and signs of inflammation of the heart or its lining.

Preparing for an ECG (EKG)

Patients undergoing an ECG lie flat on a bed or table, with leads attached to each extremity and six predefined chest positions. A small amount of gel enhances the transmission of electrical impulses to the EKG leads. These leads are attached using small suction cups, Velcro straps, or adhesive patches. The painless test typically takes around five minutes, with minimal preparation, except for potential shaving of a small amount of chest hair for optimal lead contact.

Instances for Performing an ECG (EKG)

ECGs are performed routinely as part of physical examinations, screening evaluations, cardiac stress tests, or evaluations for symptoms like chest pain, shortness of breath, dizziness, fainting, or palpitations. They are also integrated into the preoperative workup for surgery in patients where heart disease is a potential concern.

Limitations of Electrocardiogram ECG (EKG)

Despite its diagnostic capabilities, EKG has limitations. It captures a static picture and may not reveal severe heart problems when patients are asymptomatic. Some patterns observed in an EKG may be nonspecific or normal variants, requiring further examination by a physician and additional cardiac tests. In certain cases, a patient with heart symptoms might have a normal EKG, necessitating additional evaluation and testing.


While ECGs provide invaluable insights into heart health, their interpretation requires a comprehensive understanding of the patient’s medical history, symptoms, and sometimes additional diagnostic tests. These limitations emphasize the importance of collaborative and thorough healthcare assessments in ensuring accurate diagnoses and appropriate interventions.


Ajam, T, MD, et al. Electrocardiography. Medscape. Updated: Mar 11, 2019

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