What is worse: ventricular fibrillation or atrial fibrillation?

Ventricular fib: Atrial fibrillation (af) in rare instances can be a life threatening condition. However, many thousands of people each day remain in af without any limitations as long as their symptoms and risks are addressed. Ventricular fibrillation (vf) on the other hand if not treated immediately (usually by elecetrical defibrillation) is almost always uniformly fatal.

V-fib worse: Ventricular fibrillation is essentially one form of heart attack ... Atrial-fibrillation is mainly a problem if the resulting ventricular rate is very fast, which can cause a very low blood pressure ... Prolonged atrial-fibrillation can also cause a blood clot to form in the atria, which can break off and go to other parts of the body and cause problems, such as stroke if clot goes to the brain.

Ventricular fib: Vf is worse; it usually causes cardiac arrest which is often fatal. Atrial fibrillation, while not as severe, also has significant health risks. It increases the risk of stroke, which can be disabling or fatal. Additionally, if the af causes a fast pulse for a prolonged period of time, this may lead to weakening of the heart and cause heart failure.