A rapid and irregular heartbeat is auscultated in this sound.

The rhythm is irregular, but some beats are softer than others, and a grade 3-4/6 systolic murmur is heard. The murmur is louder with stronger beats (likely because of a longer diastolic interval allowing for more ventricular filling) and softer with beats that have not generated as much pressure (likely because of a shorter diastolic interval allowing for less diastolic filling). This type of rhythm, which can sound like tennis shoes in a dryer or bongo drums, is characteristic of atrial fibrillation with mitral insufficiency.