Coronary heart disease (CHD) is also called as ischemic heart disease. It is defined as "impairment of heart function due to inadequate coronary circulation". It occurs due to obstructive changes in coronary circulation of the heart.
The heart is a hollow muscular, cone-shaped organ, lying between the lungs in a block of tissue called the mediastinum. It tilts obliquely, a little more to the left than the right and presents a circular base above and an apex below.
Man has been the victim of so many known and unknown forces. There have been a number of natural calamities which do a lot of harm to man ; impersonal forces which man can neither control nor avoid interfere with their plans. But the last enemy of man has been man himself.
In Pigeon the Heart lies in the pericardium and situated in the thoracic cavity whereas in Rabit the Heart is enclosed with in the pericardium and placed in the thoracic cavity.
It is a highly muscular triangular structure formed of special cardiac muscle. Its anterior part is broad and posterior part is somewhat conical. It has four chambers two auricles and two ventricles.
Heart is located in the center of the chest cavity slightly tilted towards the left. It is a hollow muscular organ made up of cardiac muscle fibres. It is the pumping organ of the circulatory system. It has four chambers, the right and left auricles (or atria) and the right and left ventricles.