That's the answer to your description's question: before or on the 51st ball drawn. But since your heading asks a slightly different question, I'll also answer your heading's question, which is just before 51 balls.
Looking for the definition of AFIS? Find out what is the full meaning of AFIS on Abbreviations.com! 'Automated Fingerprint Identification System' is one option -- get in to view more @ The Web's largest and most authoritative acronyms and abbreviations resource.
Atrial fibrillation (AFib) is a medical disorder that affects the upper chambers, known as atria, of the heart. People with AFib experience irregular heartbeats caused by abnormal electrical signals in the atria. The electrical impulses erroneously circulate through the atria, causing the atria to contract with an irregular rhythm and fast rate.