UPDATE 1-Brazil's Congress names impeachment panel stacked against Rousseff
* Opposition wins 272-199 in controversial vote
* Secret ballot reveals deep splits in key gov't ally PMDB
* Veteran lawmaker in graft probe reportedly opts for plea (Add comments by lawmaker and analyst, political context)
By Anthony Boadle
BRASILIA, Dec 8 (Reuters) - The lower house of Brazil's Congress voted on Tuesday to appoint a committee stacked with opponents of President Dilma Rousseff to study whether to impeach her for breaking budget rules, a blow to the leftist leader battling for political survival.
In a secret ballot, lawmakers voted 272-199 for a list of committee members drawn up by the opposition and pro-impeachment members of the centrist Brazilian Democratic Movement Party (PMDB), the biggest party in Rousseff's governing coalition.
It was a clear defeat for Rousseff in the first battle of an impeachment process started last week that threatens to paralyze Congress for months, distracting policymakers from Brazil's worst recession in decades.
The vote was also a slap in the face for the leader of the PMDB party in the lower house, Leonardo Picciani, who has backed Rousseff since she appointed two ministers from his wing of the party to secure support and fend off impeachment.
Picciani's loss of face in the high-profile secret vote underscored the deep divisions within his party, which has veered away from the government in recent months as the economy plunges and a vast corruption scandal rattles the capital. Continuación...