Cardiac Rhythm Interpretation

A rhythm strip describes electrical activity; it does not, by itself, tell you whether the patient is perfusing. A rapid rhythm may be tolerated by one patient and produce shock in another, while an apparently organised tracing may accompany pulseless electrical activity. Experienced nurses therefore look at the patient first: responsiveness, palpable pulse, blood pressure, mental status, chest discomfort, work of breathing, skin temperature, and urine output establish whether the rhythm is clinically dangerous. The interpretation then becomes systematic. Rate, regularity, P waves, PR interval, QRS width, QTc, and ST-T changes reveal where impulse formation or conduction has changed. The final question is causal: is the arrhythmia driving the deterioration, or is it a response to hypoxia, ischaemia, sepsis, bleeding, pulmonary embolism, heart failure, electrolyte disturbance, or medication toxicity? That answer determines whether the priority is immediate electrical therapy, correction of a reversible cause, or monitored observation. The principles below apply to NCLEX-RN decision-making while recognising that Canadian RN authority is provincial. Defibrillation, cardioversion, pacing, and antiarrhythmic administration must be performed within the RN’s competence and the applicable provincial standards,...