Systolic anterior motion of the mitral chordae tendineae as a possible etiology for a significant left ventricular outflow tract obstruction.

Sir,

A 62-year-old obese woman with a history of atypical chest pain and cardiac murmurs was referred to our echocardiography laboratory for further evaluations. She had a history of controlled hypertension of 5 years' duration, for which she was on losartan. In physical examination, a systolic murmur (grade III/VI) was auscultated at the left parasternal border. Electrocardiography showed an intraventricular conduction delay; QRS duration was about 100 ms, left axis deviation, and QS pattern in all precordial and inferior leads with secondary ST-T changes. Despite poor echocardiography windows, transthoracic echocardiography revealed that the base and mid segments of the anteroseptal and inferoseptal walls were hypertrophied with a maximal thickness of 15 mm and a moderate-to-severe subaortic stenosis with a peak pressure gradient of 57 mmHg. Transesophageal echocardiography showed no aortic valve stenosis, no mitral valve prolapse, trivial mitral regurgitation, and a significant systolic anterior motion of the mitral chordae tendineae [Figure 1 and Video 1]. It seems that the systolic anterior motion of the mitral chordae tendineae was the main etiology of the left ventricular tract obstruction.

Figure 1

Systolic anterior motion of the mitral chordae tendineae (arrow) in transesophageal echocardiography [(a) mid-esophageal five-chamber view and (b) mid-esophageal long-axis view of the aortic valve], resulting in left ventricular outflow obstruction in color Doppler study [(c) mid-esophageal five-chamber view and (d) mid-esophageal long-axis view of the aortic valve]. LA, left atrium; LV, left ventricle; AO, ascending aorta

When we encounter dynamic left ventricular outflow tract, we expect that moderately severe mitral regurgitation would exist, but if the amount of mitral regurgitation is less than expected, mid-cavity obstruction (due to broad base of continuous wave), systolic anterior motion of posterior mitral leaflet, or systolic anterior motion of chordae tendineae as possible cause of dynamic left ventricular obstruction should be considered.[12345] Accordingly, such as presented case, cardiologists should bear in mind that the systolic anterior motion of the mitral chordae tendineae can result in a significant left ventricular outflow tract obstruction.

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