Complex sentence: The most serious signs and symptoms associated with Marfan syndrome involve the cardiovascular system: undue fatigue, shortness of breath, heart palpitations, racing heartbeats, or angina pectoris with pain radiating to the back, shoulder, or arm.
Split into simpler sentences: The most serious signs and symptoms associated with Marfan syndrome involve the cardiovascular system. Undue fatigue, shortness of breath, heart palpitations, racing heartbeats, or Angina pectoris with pain radiating to the back, shoulder, or arm.