You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

Abstract: Some patients converted from ventricular fibrillation to organized rhythms by defibrillation - trained ambulance technicians(EMT - Ds) will refibrillate before hospital arrival.The authors analyzed 271 cases of ventricular fibrillation managed by EMT - Ds working without paramedic back - up.Of 111 patients initially converted to organized rhythms, 19(17 % ) refibrillated, 11(58 % ) of whom were reconverted to perfusing rhythms, including nine of 11(82 % ) who had spontaneous pulses prior to refibrillation.Among patients initially converted to organized rhythms, hospital admission rates were lower for patients who refibrillated than for patients who did not(53 % versus 76 % , P = NS), although discharge rates were virtually identical(37 % and 35 % , respectively).Scene - to - hospital transport times were not predictively associated with either the frequency of refibrillation or patient outcome.Defibrillation - trained EMTs can effectively manage refibrillation with additional shocks and are not at a significant disadvantage when paramedic back - up is not available.
Solution: Ventricular Fibrillation
Why? This term is directly present in the abstract and it is one of the main topic in it. So can be chosen as the medical subject heading.

New input: Abstract: Forty-three patients with renal-cell carcinoma underwent treatment for spinal cord compression over a 7-year period. Of these, 32 patients underwent surgery, while 11 patients underwent radiation alone. Before operation, 25 patients had relapsed following prior radiation, while seven others received postoperative radiation. A more aggressive surgical approach, tailored to the site of compression within the spinal canal, was used with the majority undergoing gross total tumor resection by an anterior approach. Immediate stability of the spine was achieved with methyl-methacrylate reconstruction of the resected segments. Preoperative spinal angiography with embolization of hypervascular tumors was carried out in eight patients. Patient parameters in the surgical and irradiated groups were comparable, except that a greater proportion of the radiation alone group had more than one organ system involved (64% v 44%). The median survival of the surgically treated patients was 13 months, compared with 3 months for those treated by radiation alone. In addition, a greater proportion of the surgically treated patients were benefitted neurologically (70%) compared with those treated by radiation (45%). With the development of effective surgical treatment for spinal metastases, early consideration for surgical treatment (before radiation) should be considered in selected patients. Preoperative spinal angiography and embolization are recommended whenever feasible to minimize intraoperative blood loss.
Solution:
Adult