- Sinus Rhythm
- The normal heart rhythm that originates in the sinoatrial (SA) node, typically at 60–100 beats per minute in adults. It serves as the baseline against which arrhythmias are compared.
- Artifact
- Any distortion or unwanted signal on the EKG tracing that does not come from the heart, such as muscle tremor, patient movement, or electrical interference. Technicians must recognize and correct artifact so the tracing can be interpreted accurately.
- CET Scaled Passing Score
- The performance standard for the NHA Certified EKG Technician exam, which requires a scaled score of 390 or higher to pass. The 100-question exam must be completed within 120 minutes, and registration costs $117.
- P Wave
- The first deflection on the EKG, representing electrical depolarization (contraction) of the atria. An absent or abnormal P wave can signal atrial arrhythmias or conduction problems.
- QRS Complex
- The large, sharp waveform representing depolarization of the ventricles, which triggers the main pumping contraction of the heart. A widened QRS may indicate a bundle branch block or ventricular origin of the beat.
- T Wave
- The waveform that follows the QRS complex and represents repolarization (electrical recovery) of the ventricles. Peaked, inverted, or flattened T waves can indicate electrolyte imbalance or ischemia.
- Arrhythmia (Dysrhythmia)
- Any abnormality in the rate, rhythm, or origin of the heartbeat, such as atrial fibrillation or premature ventricular contractions. Identifying arrhythmias from the tracing is a core skill on the CET exam.
- Holter Monitor
- A portable device worn by a patient to continuously record the EKG over 24 to 48 hours during normal daily activity. It captures intermittent arrhythmias that a short in-office EKG might miss.
- Stress Test (Exercise Tolerance Test)
- A procedure that records the EKG while the patient exercises on a treadmill or bicycle to assess the heart's response to increased workload. Technicians monitor for rhythm changes and ST-segment shifts that suggest coronary disease.
- Electrocardiogram (ECG/EKG)
- A recording of the heart's electrical activity over time, captured as waveforms on graph paper or a monitor. It is the primary tool an EKG technician uses to detect rhythm and conduction abnormalities.
- Einthoven's Triangle
- The conceptual triangle formed by the electrodes on the right arm, left arm, and left leg that defines the three standard bipolar limb leads (I, II, III). It establishes the reference frame for measuring the heart's electrical axis.