Which rhythm is associated with a flatline on the ECG but no usable heartbeat or pulse?

Which rhythm is associated with a flatline on the ECG but no usable heartbeat or pulse?

• A. Ventricular Fibrillation (VF)
• B. Pulseless Electrical Activity (PEA)
• C. Asystole
• D. Pulseless Ventricular Tachycardia (VT)

Answer: (C)

A flat ECG tracing with no detectable heartbeat or pulse means there is no electrical activity driving the heart and no mechanical output—this is asystole. It indicates cardiac arrest with no cardiac output, and the recommended response is immediate high-quality CPR and treatment of reversible causes, plus epinephrine as indicated. Defibrillation is not used here because there’s no electrical activity to reset. By contrast, pulseless electrical activity shows some electrical activity on the ECG (the tracing is not a flat line) but the heart isn’t pumping effectively, while ventricular fibrillation and pulseless ventricular tachycardia produce abnormal, chaotic or rapid rhythms that are, unlike asystole, treatable with defibrillation.

A flat ECG tracing with no detectable heartbeat or pulse means there is no electrical activity driving the heart and no mechanical output—this is asystole. It indicates cardiac arrest with no cardiac output, and the recommended response is immediate high-quality CPR and treatment of reversible causes, plus epinephrine as indicated. Defibrillation is not used here because there’s no electrical activity to reset. By contrast, pulseless electrical activity shows some electrical activity on the ECG (the tracing is not a flat line) but the heart isn’t pumping effectively, while ventricular fibrillation and pulseless ventricular tachycardia produce abnormal, chaotic or rapid rhythms that are, unlike asystole, treatable with defibrillation.