Musical murmur in a dog with acute chordae tendineae rupture

Abstract

: A 6 year-old, spayed female, Maltese dog was presented with precordial thrill and mild coughing. Thoracic auscultation revealed a grade V/VI systolic murmur with maximal intensity over the left apex characterized by musical murmur. Echocardiography revealed mild myxomatous degeneration of mitral valve and ruptured chordae tendineae. Musical murmur was produced due to the vibration of ruptured piece of chordae tendineae along with regurgitant flow. After treatment with furosemide and ramipril, clinical signs resolved and precordial thrill reduced. This case report describes typical clinical signs and phonocardiogram of musical murmur in a dog with acute chordae tendineae rupture.Keywords : chordae tendineae rupture, mitral valve disease, musical murmur Mitral valve disease (MVD) is the most common acquired heart disease in small breed-dogs and characterized by myxomatous valvular degeneration [3,5,6,7,8]. It results in mitral valve insufficiency creating systolic mitral regurgitation, which in turn leads to a left apical systolic murmur [7]. Usually with MVD, systolic murmur intensity is related to disease severity. However, occasionally with mild stage of MVD, the murmur has a musical quality and striking intensity [9].This case describes sudden onset of precordial thrill characterized as musical murmur resulted from acutely ruptured chordae tendineae with midly degenerated mitral valve.A 6 year-old, spayed female, Maltese dog was presented with sudden onset of precordial thrill and mild nocturnal coughing. Thoracic auscultation revealed a grade V/VI systolic murmur with maximal intensity over the left apex. Laboratory data including a complete blood count, serum biochemical analysis were within normal ranges. Evaluation of the electrocardiogram showed mildly prolonged P wave. Thoracic radiography revealed bronchointerstitial pattern in bilateral caudal lung lobes. 2D-echocardiography demonstrated slightly thickened mitral valve and pieces of ruptured chordae tendineae attached to the tip of mitral valve leaflet (Fig. 1). Doppler echocardiography revealed mild systolic turbulent flow in the left atrium running around atrial wall with peak velocity 2.07 m/sec and pressure gradient 17.2 mmHg (Fig. 1). There was no marked evidence of cardiac remodeling. Phonocardiography was performed, and showed mid-systolic diamond shape murmur with variable amplitudes (Fig. 2). Recorded sound files of phonocardiogram revealed sharp, pitched 'wheeping' sound, characterized as musical murmur. The blood sample collected aseptically was submitted for aerobic and anaerobic blood culture, and the result was negative. Based on the physical and clinical examination, the dog was diagnosed as mitral valve degeneration (MVD) with chordae tendineae rupture (CTR). Furosemide (Lasix, 0.5 mg/kg, oral, twice daily; Handok phrmaceuticals, Korea) and ramipril (Vasotop, 0.125 mg/kg, oral, once a daily; Intervet, Korea) were administered. After