Systolic anterior motion of the mitral valve associated with right ventricular systolic hypertension in 9 dogs.
OBJECTIVE
To describe the zoographic and echocardiographic characteristics of canine patients in which systolic anterior motion of the mitral valve (SAM) was identified in association with right ventricular systolic hypertension (RVSH).


METHODS
Medical records and digitally recorded echocardiographic examinations were reviewed for RVSH and two-dimensional (2DE) or M-mode echocardiographic evidence of SAM.


RESULTS
SAM was identified in association with RSVH in 9 patients; 5 had pulmonic stenosis, 2 had tetralogy of Fallot and 2, pulmonary hypertension. Relative to body weight, the end-diastolic and end-systolic left ventricular dimensions were subnormal in all patients. Hyperdynamic left ventricular systolic performance was identified in 8 of 9 patients. In 5 of the 9 patients, SAM was mild or moderate in degree. Left ventricular outflow tract (LVOT) obstruction and mitral valve regurgitation were documented by Doppler studies in only 3 of the 4 patients with marked SAM. However, late systolic acceleration within the LVOT was recorded in 2 additional patients for whom peak velocities were normal.


CONCLUSIONS
In the cases described here, the presence of SAM is likely explained by alterations in left ventricular geometry and function associated with diminished pulmonary venous return together with sympathetic activation resulting from subnormal stroke volume. Although the hemodynamic consequences were apparently minor, the association of SAM with right-sided heart disease might be of interest to those engaged in the practice of veterinary echocardiography.
Paige
Christopher F
CF
Department of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Phase II Duckpond Drive, Blacksburg, VA 24061, USA.
Abbott
Jonathan A
JA
Pyle
R Lee
RL
D000818:Animals; D004283:Dog Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004285:Dogs; D015150:Echocardiography, Doppler / Q000379:methods / Q000662:veterinary; D005260:Female; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000662:veterinary; D008297:Male; D008943:Mitral Valve / Q000503:physiopathology*; D011666:Pulmonary Valve Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000662:veterinary; D012189:Retrospective Studies; D013599:Systole; D013771:Tetralogy of Fallot / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000662:veterinary; D018497:Ventricular Dysfunction, Right / Q000662:veterinary*; D016278:Ventricular Function, Right / Q000502:physiology*; D014694:Ventricular Outflow Obstruction / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000662:veterinary*