What feature of an innocent murmur is commonly observed during physical examination?

An innocent murmur is characterized by specific features that make it distinctively benign. One of the key features is that it can often disappear with increased cardiac output, which occurs during situations like exercise or fever when the heart pumps harder and faster. This characteristic reflects the physiological nature of innocent murmurs, which typically arise from increased blood flow across normal heart structures, rather than from inherent structural abnormalities.

Innocent murmurs are typically heard when blood flows more rapidly through the heart or major vessels, like during periods of increased heart rate or volume. The fact that the murmur can disappear during higher output situations further supports its classification as innocent, as it denotes that it is not caused by any pathological condition that would persist regardless of the heart's workload.

Understanding this aspect of innocent murmurs is crucial, as it helps differentiate them from pathological murmurs that may remain present despite changes in blood flow dynamics and can indicate underlying heart issues.