a cardiologist is a doctor with special training on the heart. the doctor in this field ensures the heart is healthy and functions properly. the heart is a vital organ whose role is to pump blood to the rest of the body. the purpose of blood is to deliver oxygen to the tissues. without the heart functioning well, our tissues and organs would die and not function properly. cardiologists treat heart attacks, sudden cardiac arrests, arrhythmias (rhythm issues related to a faulty electrical system of the heart), heart failure (where the heart fails to pump blood forward properly) and many other heart related illnesses. they specialize in life saving procedures like cardiac stents and cardiac ablation. there is a subspecialty within cardiology called "interventional cardiology." these are cardiologists who specialize in interventions or procedures to save the function of the heart, such as cardiac stenting or angiography.