Introduction

Abnormal heart sounds are called cardiac murmurs or bruits. The abnormal sounds are produced because of the change in the pattern of blood flow. Normally, blood flows in stream line through heart or the blood vessels. However, during the abnormal conditions like valvular diseases, the blood flow becomes turbulent. This produces the cardiac murmurs.

The cardiac murmurs are heard by placing the chest piece of the stethoscope over the auscultatory areas. The murmurs due to disease of a particular valve is heard better over the auscultatory area of that valve. Sometimes, the murmurs are felt by palpation as “thrills”. In some patients, the murmurs are heard without any aid even at a distance of few feet away from the patient.

The murmurs are produced during the valvular diseases and the other diseases like septal defects and defects in the blood vessels. The valvular diseases are of two types, the stenosis and incompetence.

Stenosis

The narrowing of the valve is called stenosis. The blood flows rapidly with turbulence through the narrow orifice of the valve resulting in murmur.

Incompetence

Weakening of the valve in the heart is called incompetence. When the valve becomes weak, there is back flow of blood, which causes turbulence. The disease is also called regurgitation or valvular insufficiency.

Classification of murmurs

Murmurs are classified into three types.
1. Systolic murmur, which is produced during systole
2. Diastolic murmur, which is produced during diastole of the heart
3. Continuous murmur, which is produced continuously.

Causes for cardiac murmurs

Systolic murmur
• Incompetence of atrioventricular valves
• Stenosis of semi lunar valves
• Anemia
• Septal defect
• Coarctation of aorta

Diastolic murmur
• Stenosis of atrioventricular valves
• Incompetence of semi lunar valves

Continuous murmur
• Patent ductus arteriosus