NHA Certified Clinical Medical Assistant (CCMA)Clinical Patient CareHard
A medical assistant is performing an electrocardiogram (ECG) on a patient. The MA notices that the P waves are absent, and the QRS complexes are wide and irregular. The patient reports feeling lightheaded. Which of the following cardiac arrhythmias is most likely occurring?
- AVentricular fibrillation
- BAsystole
- CSinus bradycardia
- DAtrial fibrillation
Show answer & explanationAnswer & explanation
Correct answer: A. Ventricular fibrillation
Absent P waves, wide and irregular QRS complexes, and a patient feeling lightheaded are classic signs of ventricular fibrillation (V-fib), a life-threatening arrhythmia where the ventricles quiver uselessly instead of pumping blood. Sinus bradycardia has normal P waves and narrow QRS, atrial fibrillation has absent P waves but narrow and irregular QRS, and asystole is a flat line (no electrical activity).
Why the other options are wrong
- B. Asystole is a complete absence of electrical activity (a flat line) and would not present with QRS complexes.
- C. Sinus bradycardia would show normal P waves, narrow QRS complexes, and a slow heart rate.
- D. Atrial fibrillation would show absent P waves and an irregularly irregular rhythm, but the QRS complexes would typically be narrow, not wide.
Ventricular Fibrillation (V-fib)
A life-threatening cardiac arrhythmia characterized by disorganized electrical activity in the ventricles, leading to ineffective contraction and no blood flow.
- ECG: absent P waves, wide/bizarre/irregular QRS complexes.
- Clinical: patient is unconscious, pulseless, no breathing (unless brief onset).
- Requires immediate defibrillation (shock).
- Often precedes asystole if not treated.
Memory trick: P for Atria, QRS for Ventricles, T for Repolarize