Phonocardiogram of aortic regurgitation as heard at the lower left sternal border

Carotid artery pulse tracing and phonocardiogram of aortic regurgitation as heard at the fourth left intercostal space. S1 (mitral and tricuspid valve closure) is followed by a short midsystolic ejection murmur resulting from the large stroke volume seen in aortic regurgitation. Following S2 (aortic and pulmonic valve closure), there is a holodiastolic blowing murmur of aortic regurgitation (AR).