A combination grade 4/6 harsh ejection type (crescendo) systolic murmur with a soft grade 2/6 diastolic murmur (auscultated over the left heart base) caused by severe pulmonic stenosis and mild pulmonic insufficiency is appreciated in this dog (prior to balloon valvuloplasty).
The combination of a systolic ejection murmur with a diastolic decrescendo murmur is described as a to-and-fro murmur. The ejection component tapers in late systole, allowing recognition of S2 and differentiation from a continuous murmur. This dog had severe outflow tract obstruction and moderate pulmonary insufficiency prior to the balloon valvuloplasty.