ECG and Cardiology Vocabulary
Fundamentals of Cardiology and Diagnostic Principles
Cardiology: The specialized study of the heart and its associated diseases.
Echocardiography: A diagnostic procedure involving the use of ultrahigh-frequency sound waves directed toward the heart. It is utilized to evaluate both the function and the structural integrity of the organ.
Echoes: These are defined as reflections of sound, which are utilized in imaging procedures like echocardiography.
Stress tests: Diagnostic procedures used to gather information regarding how the heart functions during periods of physical activity.
Sedentary: A term pertaining to sitting or characterized by physical inactivity.
The Electrocardiogram (ECG): Recording and Instrumentation
Electrocardiogram: A graphic record of the electric currents generated by the heart, also known as a tracing of heart action. It may be referred to interchangeably as an ECG or an EKG.
Amplifier: A specific device integrated into an electrocardiograph that functions to enlarge the ECG impulses for better visibility and analysis.
Electrodes: Also known as sensors, these are instruments with a point or a surface that transmit electrical current to the patient’s body. They conduct electricity from the body to the electrocardiograph.
Galvanometer: An instrument utilized to measure electrical current through the application of electromagnetic action.
Stylus: A pen-like instrument that serves as the ECG writer.
Tracing: The production of a sketch or graphic record by means of a stylus passing over paper, as seen in the process of electrocardiography.
Interpretive: Refers to the computerized analysis of ECG tracings to assist in diagnosis.
Multichannel: Refers to the capability of modern ECG equipment to process electrical impulses from multiple leads simultaneously.
Mechanical: A descriptive term pertaining to machinery or mechanized processes.
Standardization: The process of bringing something into conformity with a set standard. In the context of an ECG, it refers to a specific mark made at the beginning of each lead to establish a standard of reference for measurement.
Reliable: A term used to describe equipment or data that is dependable and can be consistently relied upon.
Cardiac Electrophysiology and Physiological Processes
Impulses: A charge transmitted through specific tissues, particularly nerve fibers and muscles, resulting in physiologic activity.
Current: Represents the heart’s electrical activity presented as waveforms moving through the heart tissue.
Atrial Depolarization: The state of excitement and subsequent contraction caused by the SA node at the very beginning of the cardiac cycle.
Repolarization: The reestablishment of a polarized state in a muscle or nerve fiber following contraction or the conduction of a nerve impulse. On an ECG tracing, this represents the time of recovery required before another contraction can occur.
Purkinje: A specialized network of fibers found within the cardiac muscle that carries the electrical impulses specifically responsible for the contraction of the ventricles.
Somatic: Pertaining to the physical body as distinguished from the mind. This also refers to the structures of the body wall, such as the skeletal muscles.
ECG Waveform Components and Anatomical Considerations
Segments: The specific portion of an ECG tracing that exists between two waves.
Intervals: The time elapsed between events or the space between them. On an ECG, an interval is the period that includes one segment and one or more waves (e.g., the P-R interval).
Precordial: Pertaining to the specific area of the chest wall located directly over the heart, used for the placement of ECG chest leads.
Limbs: Refers specifically to the arms and legs of the patient.
Augmented: In a standard -lead ECG tracing, this refers to leads , , and . These particular leads utilize different levels of voltage.
Signal Quality and Interference
Interference: The confusion or disruption of desired signals caused by undesired signals, often manifesting as artifacts on an ECG.
Artifacts: Something extraneous to the data being sought; in electrocardiography, this refers to activity that causes interference on the ECG tracing.
Intermittent: This describes a pattern of stopping and starting again at various intervals.
Simultaneous: Occurring at the exact same time.
Emergency Cardiac Intervention and Electrical Force
Voltage: A measure of electromotive force within an electrical system.
Countershock: In cardiology, this is a high-intensity, short-duration electric shock applied to the area of the heart. The goal is to achieve total cardiac depolarization.
Defibrillator: A device designed specifically to deliver an electric shock to a patient in an effort to terminate pulseless ventricular fibrillation or ventricular tachycardia.