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A male patient aged 38 years had hypertrophic cardiomyopathy (HCM) diagnosed in adolescence. One year before the present evaluation he was mildly symptomatic and taking propranolol 240 mg/day. Doppler echocardiography showed massive hypertrophy (septum, 32 mm; posterior wall, 22 mm), a normal left ventricular cavity and fractional systolic shortening, systolic anterior motion of the mitral valve touching the septum, and a resting peak systolic gradient of 105 mm Hg in the left ventricular outflow tract (LVOT). Recently, despite unchanged clinical status, the echocardiographic findings became quite different. Both the systolic anterior motion and the gradient (laminar systolic flow in the LVOT) disappeared. New images suggested mitral valve prolapse and rupture of the chordae tendineae. Septal and wall thicknesses decreased to 22 mm and 14 mm, respectively. The left ventricular diastolic internal diameter increased from 46 mm to 49 mm; fractional shortening did not change.
Transoesophageal echocardiography confirmed the diagnosis of multiple chordae rupture. Both mitral leaflets were prolapsed leading to a significant regurgitation (fig 1–5).
In HCM, ruptured mitral chordae tendineae is an infrequent complication. Few single case reports can be found in the literature1,2; five cases reported by Zhu et al3 are of note. The rupture can be spontaneous or secondary to infective endocarditis and is generally followed by acute haemodynamic deterioration requiring immediate surgical intervention.
The present case has unique features. Unlike in previously reported cases, the present patient’s symptoms did not worsen. The rupture caused prolapse of the medial portions of both mitral leaflets, originating a curious bidirectional regurgitant jet and, importantly, completely relieving the severe LVOT obstruction. We can speculate that the clinical status was unchanged because the overload imposed by the regurgitation was counterbalanced by the disappearance of the obstructive gradient.
In HCM, the mitral valve apparatus has a critical role in the genesis of LVOT obstruction. A constellation of structural malformations can be present such as enlarged or elongated leaflets and abnormal papillary muscle insertions.4 Coexistence of mitral valve prolapse and HCM is considered infrequent (3%).5
The best surgical procedure to alleviate obstruction in HCM has been the subject of debate. Septal myectomy (Morrow’s surgery), combined myectomy and mitral surgery (repair or replacement), and mitral surgery alone have been the most commonly performed.6–8 The choice of the appropriate technique is based on careful preoperative and transoperative morphological evaluation, in addition to the surgeon’s preference.
In view of the present case, in which the mitral valve seemed to be the principal and perhaps the only mechanism of obstruction, surgeons must keep in mind the possibility of relieving the obstruction through a single valve repair in selected cases of obstructive HCM.
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