Left ventricular geometrical differences in dogs with various stages of myxomatous mitral valve disease

To evaluate left ventricular geometry in dogs with various stages of myxomatous mitral valve disease.

Ninety-seven dogs with myxomatous mitral valve disease classified by the International Small Animal Cardiac Health Council system and 20 weight- and age-matched healthy dogs. Left ventricular long-axis to short-axis ratio, sphericity index in end-diastole and end-systole, left ventricular wall thickness to internal dimension ratio and relative wall thickness were assessed.

The diastolic sphericity index was lower in classes Ib, II and III than in healthy dogs (P=0·003, P<0·001 and P<0·001) and was also lower in class III than in classes Ia, Ib and class II dogs (P<0·001, P<0·001 and P=0·002). The relative wall thickness was lower in classes II and III than in class Ia (P=0·003 and P<0·001), class Ib (P=0·004 and P<0·001), and healthy dogs (P<0·001 and P<0·001) and was also lower in class III than in class II (P=0·005).

Sphericity index and relative wall thickness are simple methods for assessing left ventricular geometry using two-dimensional echocardiography that may be useful in myxomatous mitral valve disease dogs as part of risk stratification.