HARRISBURG, Pa. (AP) — U.S. Sen. John Fetterman had what his office says was a “ventricular fibrillation flare-up” that caused him to feel light-headed and fall during an early morning walk. His office says Fetterman was doing well Thursday and hospitalized in Pittsburgh. He sustained minor injuries to his face and was under “routine observation” at the hospital while doctors fine-tune his medication regimen. The American Heart Association says ventricular fibrillation is the most serious form of abnormal heartbeat and can lead to cardiac arrest, when the heart suddenly stops beating. Fetterman suffered a stroke in 2022 and disclosed afterward that he was diagnosed with cardiomyopathy and another type of abnormal heartbeat, atrial fibrillation.