His compositions include works for orchestra, vocal and instrumental chamber music, with electronics and computer devices.
Among his teachers are Antonio Mastrogiovanni, Eduardo Kusnir, Geert van Keulen, Ton de Leeuw, Louis Andriessen, Theo Loevendie, John Coolidge Adams and Trevor Wishart.
[5] He has written works commissioned by the Teresa Carreño Opera Theatre, the Venezuelan Society for Electronic Music, the Swedish Arts Grants Committee, the Swedish Arts Council,[6] Caracas Ensemble, Nova Musica Ensemble, STIM, the Stockholm Saxophone Quartet,[7] Gageego!,[8] Ars Nova, and Concerts Sweden.
Varela taught at the National Conservatory of Music J.J. Landaeta and at IUDEM, both in Caracas.
He has also been a lecturer at the Universities Central de Venezuela, Simón Bolívar, Stanford, and Gothenburg.