Which of the following is not a shockable rhythm?
A. Asystole
B. Ventricular fibrillation
C. Pulseless electrical activity
D. Ventricular tachycardia
The correct answer and explanation is:
The correct answer is A. Asystole.
Explanation:
In the context of cardiac arrest and resuscitation, certain heart rhythms can be treated with defibrillation (shocking), while others cannot. These rhythms are generally classified into two categories: shockable and non-shockable rhythms.
- Ventricular Fibrillation (VF): This is a disorganized electrical activity in the ventricles that causes the heart to quiver instead of contracting normally. This results in no effective blood circulation. VF is a shockable rhythm, and defibrillation is often the first line of treatment to restore a normal rhythm.
- Ventricular Tachycardia (VT): This is a fast heart rhythm originating in the ventricles. It can be either pulseless or with a pulse. If the patient is pulseless, VT is considered a shockable rhythm. If there is a pulse, treatment usually involves medications and monitoring.
- Pulseless Electrical Activity (PEA): This refers to a situation where there is electrical activity in the heart (shown on the electrocardiogram) but no effective mechanical heart contractions, meaning no pulse. This is a non-shockable rhythm because it is not due to arrhythmias that can be reset by a shock. Instead, treatment focuses on addressing the underlying cause, such as hypoxia, hypovolemia, or electrolyte imbalances.
- Asystole: This is the complete absence of electrical activity in the heart. In other words, it is flatlining on the ECG. Asystole is a non-shockable rhythm because there is no electrical activity to reset or restart with a shock. The treatment for asystole primarily involves high-quality cardiopulmonary resuscitation (CPR) and administration of medications like epinephrine.
In summary, while ventricular fibrillation, pulseless ventricular tachycardia, and ventricular fibrillation are shockable rhythms that can be treated with defibrillation, asystole is not. The treatment for asystole involves medical management and CPR rather than defibrillation.