Which type of murmur extends throughout both the systolic and diastolic phases?

A continuous murmur is characterized by its presence throughout both the systolic and diastolic phases of the cardiac cycle. This type of murmur typically indicates a persistent abnormal flow of blood, often arising from conditions such as a shunt (e.g., a patent ductus arteriosus) or ongoing turbulence resulting from vascular malformations.

In contrast, other types of murmurs, such as systolic or diastolic murmurs, are confined to specific phases of the cardiac cycle. A systolic murmur occurs only during ventricular contraction, while a diastolic murmur appears solely during ventricular relaxation. Additionally, the classification of a murmur based on grading (such as Grade III) refers to the intensity of the sound rather than its timing within the cardiac cycle. Thus, these classifications do not include the continuous nature that distinguishes continuous murmurs, making them less applicable to this particular question.