A 56-year-old man is admitted to the hospital with chest discomfort. He is placed on telemetry and treated with intravenous nitroglycerin and heparin. Two hours after admission, he is noted to have a rapid, wide complex tachycardia and no blood pressure is obtained.
CPR is initiated and an electric shock from a defibrillator is given (image). There isa change in the rhythm but a blood pressure is still not obtained.
Why was the electric shock ineffective and what happened?