What is the term for an abnormal heart sound often described as a whisper?

The term that refers to an abnormal heart sound, often described as a whisper, is a heart murmur. A heart murmur occurs when blood flows through the heart's chambers or valves in a way that produces unusual sounds, typically during the heartbeat. This can be due to various reasons, such as turbulent blood flow or structural abnormalities within the heart.

In clinical settings, murmurs can be detected using a stethoscope and are an important diagnostic tool. While some murmurs are benign and do not indicate serious health issues, others may suggest underlying problems such as valve defects or heart conditions, necessitating further evaluation.

The other terms like heartbeat, arrhythmia, and palpitation do not refer to abnormal sounds. A heartbeat is the normal rhythm and sound produced by the heart, arrhythmia refers to irregular heartbeats, and palpitations describe the sensation of feeling one's own heartbeat, which may or may not indicate a murmur or underlying heart condition.