## Overview A cardiac murmur is an abnormal heart sound produced by turbulent blood flow. Mitral and aortic regurgitation are the most common significant murmurs in older horses (mitral is often equal or more frequent than aortic in studied populations). Many murmurs are incidental and do not affect performance; others indicate clinically important valvular disease that can limit athletic use or, rarely, lead to heart failure. ## Causes Degenerative valve disease (mitral and aortic valves are both commonly affected), congenital defects such as ventricular septal defect or patent ductus arteriosus, and endocarditis are the main causes. Physiologic (innocent) murmurs also occur, particularly in fit young horses. ## Diagnosis Auscultation detects the murmur and characterizes its timing, location, and intensity. Echocardiography with Doppler is required to determine the valve involved, the severity of regurgitation, and the effect on chamber size and function. ## Treatment Most murmurs require only monitoring. Horses with significant regurgitation may need exercise restriction and periodic re-evaluation. Specific medical or surgical therapy is rarely indicated except for selected congenital lesions or endocarditis. ## Recovery and Prognosis Prognosis depends on the lesion. Mild valvular regurgitation (whether mitral or aortic) is often well tolerated for years. Severe regurgitation or myocardial dysfunction carries a guarded prognosis for continued athletic work and, in advanced cases, for life. ## Prevention No specific prevention exists for degenerative valve disease. Regular auscultation allows early detection.
abnormal heart sound on auscultation; exercise intolerance in significant cases; elevated resting heart rate; jugular pulsation or edema in advanced heart failure
## Overview A cardiac murmur is an abnormal heart sound produced by turbulent blood flow. Mitral and aortic regurgitation are the most common significant murmurs in older horses (mitral is often equal or more frequent than aortic in studied populations). Many murmurs are incidental and do not affect performance; others indicate clinically important valvular disease that can limit athletic use or, rarely, lead to heart failure. ## Causes Degenerative valve disease (mitral and aortic valves are both commonly affected), congenital defects such as ventricular septal defect or patent ductus arteriosus, and endocarditis are the main causes. Physiologic (innocent) murmurs also occur, particularly in fit young horses. ## Diagnosis Auscultation detects the murmur and characterizes its timing, location, and intensity. Echocardiography with Doppler is required to determine the valve involved, the severity of regurgitation, and the effect on chamber size and function. ## Treatment Most murmurs require only monitoring. Horses with significant regurgitation may need exercise restriction and periodic re-evaluation. Specific medical or surgical therapy is rarely indicated except for selected congenital lesions or endocarditis. ## Recovery and Prognosis Prognosis depends on the lesion. Mild valvular regurgitation (whether mitral or aortic) is often well tolerated for years. Severe regurgitation or myocardial dysfunction carries a guarded prognosis for continued athletic work and, in advanced cases, for life. ## Prevention No specific prevention exists for degenerative valve disease. Regular auscultation allows early detection.
abnormal heart sound on auscultation; exercise intolerance in significant cases; elevated resting heart rate; jugular pulsation or edema in advanced heart failure