In the flashback where Clay is initially rushed to the ER, Dr. Harper says 'We have a massive heart attack, possible MI'. MI is an abbreviation for myocardial infarction which is commonly known as a heart attack.
The surgeon starts prepping the op site even before the anesthesiologist intubates the patient. Usually you first sedate, then anesthetize & intubate the patient before any preparations starts b/c the sedatives and hypnotics tend to make a person susceptible to hallucinations & bad trips that could be triggered by sensory input (noise, light, the cold from the disinfectant).
Clay's heart shows an asystole on the EKG monitor, yet the surgeon yells "V-Fib" (Ventricular Fibrillation) and calls for the defibrillator, clearly he is not in Ventricular Fibrillation but in asystole, and asystole i.e. non-beating heart, cannot and must not be defibrillated.
The goof items below may give away important plot points.
Lilith's heart would not be available for transplant in the scenario as it is shown. In real life, she would have been intubated and had multiple IV access and monitoring sites, and the hospital would have had to go through the process of having her declared brain dead before her organs could be removed.
By overdosing on isosorbide or any other of her son's medications, Lillith would have caused her own blood pressure to drop, therefore jeopardizing the health of her heart. It's likely that she would have known the effects of the medication, and not chosen to use them for an overdose.
The new surgeon states they used Adriamycin to 'spike' the new heart. Adriamycin is a chemotherapeutic agent that is red in color. The syringe that Sam hands to Jack is filled with a clear and colorless liquid, however, the new surgeon was merely speculating what might have been used.