A third scenario would be the status quo, Carrasquero said, but sooner or later, a new presidential vote seems "inevitable." He and other analysts say it's hard to predict how long that might take.
The Venezuelan Constitution says that if a president dies or steps down, a new vote must be called and held within 30 days. Chavez raised that possibility before he left for Cuba in December by saying that if necessary, Maduro should run in a new election to replace him.
Asked about Chavez's return, U.S. State Department spokeswoman Victoria Nuland noted the possibility of a new vote.
"It is obviously a matter for Venezuelans to decide how the transition is going to take place," Nuland told reporters in Washington on Tuesday. She said "we would hope that that election would be free and fair and balanced," and that there would be open media access.
On Monday night, Maduro and other Cabinet ministers held hands and prayed in a televised gathering where a priest and a minister offered words of thanks for Chavez's return.
"He will live and he will triumph," Maduro said earlier while leading a Cabinet meeting on Monday night. As the meeting ended, on television an image of Chavez's face was superimposed on the oval-shaped table.
Officials have confirmed that Chavez is breathing through a tracheal tube, but it's unclear if he is breathing on his own or is relying on a ventilator.
"It is possible that he has a tracheostomy without being ventilator-dependent, although it isn't clear why that would be the case," said Dr. Steve Hahn, a professor of radiation oncology at the University of Pennsylvania's Perelman School of Medicine.
Hahn, who is not involved in Chavez's treatment, said swallowing usually becomes difficult, though not impossible, for patients who have undergone the procedure and have a hole in the windpipe.
The alternatives for patients who can no longer swallow include a tube coming out of the stomach or the nose, or intravenous feeding, Hahn said. "The patient may not be receiving IV fluids or antibiotics, although they often are."
Hahn said that given Chavez's treatment regimen and evolution, he could have a low-grade sarcoma that is continuing to come back.
"It certainly sounds like he is receiving palliative chemotherapy," Hahn said. "It does sound as if his situation is incurable and most likely end-stage."
Associated Press writers Fabiola Sanchez and Ian James in Caracas, Paola Flores in La Paz, Bolivia, and Bradley Klapper in Washington contributed to this report.
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