Defibrillation waveforms for VF/VT can be monophasic or biphasic; which is preferred?

Defibrillation waveforms for VF/VT can be monophasic or biphasic; which is preferred?

• A. Monophasic
• B. Biphasic
• C. Multiphasic
• D. Nonphasic

Answer: (B)

Defibrillation effectiveness and safety improve when the shock waveform uses two phases with opposite polarity. Biphasic defibrillation delivers current in two sequential phases, which more reliably depolarizes the heart across varying chest impedances and disruptions in the cardiac conduction system. This means you can achieve successful termination of VF/VT with much lower energy, reducing myocardial injury and improving overall outcomes, including higher first-shock success and better survival. In contrast, monophasic shocks require higher energy to achieve similar results and cause more cardiac damage. Other waveforms like multiphasic or nonphasic aren’t standard in modern defibrillators, so biphasic is the preferred approach.

Defibrillation effectiveness and safety improve when the shock waveform uses two phases with opposite polarity. Biphasic defibrillation delivers current in two sequential phases, which more reliably depolarizes the heart across varying chest impedances and disruptions in the cardiac conduction system. This means you can achieve successful termination of VF/VT with much lower energy, reducing myocardial injury and improving overall outcomes, including higher first-shock success and better survival. In contrast, monophasic shocks require higher energy to achieve similar results and cause more cardiac damage. Other waveforms like multiphasic or nonphasic aren’t standard in modern defibrillators, so biphasic is the preferred approach.