A combination of systolic and diastolic murmurs caused by mitral valve dysplasia is auscultated in these feline heart sounds.
The mitral valve dysplasia causes both mitral insufficiency (systolic component) with diastolic murmur (during the passive/early and active/late phases of left ventricular filling). This is described as a to-and-fro murmur; the systolic component tapers in late systole, allowing recognition of S2 and differentiation from a continuous murmur. Also in this recording, there is an extra systole caused by an atrial premature contraction.