Also known as: Heart attack
Keith presents with chest pain after an acute MI, but scans reveal a large coronary artery aneurysm with a fistula into a heart chamber rather than a tumor. His fiancée Amy leaves him before surgery due to being unable to handle the situation, but he survives the high-risk operation.
Also known as: GCA - Giant coronary aneurysm
Keith's coronary artery aneurysm with fistula is extremely delicate with high risk of rupture during surgery or in daily life. Burke successfully operates despite the high-risk nature of the lesion.
Also known as: Head laceration
11-year-old boy hit by a baseball while playing first base presents with vomiting. CT reveals intracranial bleeding that progresses to acute hydrocephalus requiring emergency cranial access procedure to relieve pressure.
Also known as: Fluid buildup in brain
Shawn develops acute hydrocephalus from his head injury, becoming altered and requiring Derek to drill a burr hole to relieve intracranial pressure at bedside with parents present.
Also known as: CHF
Denny, awaiting heart transplant, is admitted with acute dysrhythmia and worsening CHF. He develops rapid atrial fibrillation requiring synchronized cardioversion. Izzie shows increasing emotional attachment to him as his condition remains unstable.
Also known as: A-fib
Denny develops rapid atrial fibrillation with unstable vitals requiring electrical cardioversion to restore normal rhythm. Burke warns that he's just going to be okay until he suddenly isn't without a transplant.
Also known as: Poison ivy
Addison develops severe poison oak in her genital area after squatting outside the trailer to urinate. Bailey treats her with calamine lotion and steroids, noting it's the worst case she's seen. Used for comic relief and karma theme.