Complex sentence: Dr. Antonio Fernós-Isern (May 10,1885--January 19,1974) born in San Lorenzo, Puerto Rico was the first Puerto Rican cardiologist and longest serving "Resident Commissioner".
Split into simpler sentences: Dr. Antonio Fernós-Isern (May 10,1885--January 19,1974) born in San Lorenzo, Puerto Rico-cardiologist. Fernos-Isern was the first Puerto Rican cardiologist and its longest serving "Resident Commissioner".