AFTER DEPARTING THE ST. CLAIR AIRPORT ESTABLISHING A NORMAL CLIMB TO THE DESTINATION AIRPORT 24 MILES TO THE NORTHEAST, THE ACFT WAS TRACKED BY RADAR FOR A FOUR MINUTE PERIOD. THE SHORT PERIOD OF COVERAGE SHOWED A NORMAL CLIMB TOLEVEL FLIGHT. THE RADAR IMAGE WAS LOST AT A TOWN APPROXIMATELY 8.5 MILES NORTHEAST OF THE DEPARTURE AIRPORT. THE ACFT WAS FOUND IMPACTED THROUGH A SMALL PENINSULA SHAPED AREA OF FORESTATION. THIS AREA WAS BOUNDED BY A RATHER LARGE AREA OF OPEN SLIGHTLY ROLLING, BUT LEVEL TERRAIN. NO MECHANICAL ABNORMALITY WAS DISCOVERED DURING THE POST-CRASH INVESTIGATION. THE PLT WAS MEDICALLY DOCUMENTED AS HAVING WOLFF-PARKINSON-WHITE SYNDROME WITH DOCUMENTED ARRHYTHMIAS. THIS CONDITION CAN HAVE PERIODS OF LOSS CONCIOUSNESS. THE PLT WAS TAKING NO MEDICATION FOR THIS CONDITION. THE AREA BOUNDING CRASH SITE WAS OF SUFFICIENT LENGHT AND WIDTH TO ACCOMODATE THIS ACFT FOR A LANDING.