A MAN DROWNED ON SIESTA KEY BEACH FRIDAY, BUT OFFICIALS BELIEVE HE MAY HAVE SUFFERED A HEART ATTACK.  SARASOTA COUNTY DEPUTIES SAY THEY WERE CALLED TO THE BEACH JUST BEFORE 6:45PM FRIDAY WHEN WITNESSES SAY 66 YEAR OLD ENRICO INGRATTA WENT INTO THE WATER AND SHORTLY THEREAFTER APPEARED TO GO UNDER WITHOUT SURFACING.  SEVERAL PEOPLE PULLED INGRATTA FROM THE WATER AND LIFEGUARDS ADMINISTERED CPR, AND HE WAS TAKEN TO SARASOTA MEMORIAL HOSPITAL WHERE HE WAS PRONOUNCED DEAD A SHORT TIME LATER.  OFFICIALS SAY THERE WERE NO RIP CURRENTS OR OTHER WATER HAZARDS AT THE TIME OF THE INCIDENT.