Acute severe mitral regurgitation: consideration of papillary muscle architecture

Login or register to view PDF.
Abstract

We present a case of an individual who presented with acute severe mitral regurgitation in the setting of an inferior ST elevation myocardial infarction. Both transthoracic and transesophageal echocardiography demonstrated a posteriorly directed eccentric jet of severe mitral regurgitation with flail anterior mitral valve leaflet attached presumably to the anterior papillary muscle. Intraoperative findings demonstrated rupture of the postero-medial papillary muscle attached via chords to the anterior mitral valve leaflet. This case serves to remind us that both the anterior and posterior leaflets of the mitral valve are attached to both papillary muscle heads. The direction and eccentricity of the mitral regurgitant jet on echocardiography helps to locate the leaflet involved, but not necessarily the coexisting papillary muscle pathology.

Pages

Introduction
Echocardiography is the primary imaging modality of choice for the noninvasive assessment of mechanical complications such as acute mitral regurgitation in the setting of myocardial infarction (MI). Echocardiographic features of importance include location of the papillary muscle rupture and leaflet involvement, direction and severity of mitral regurgitation, and hemodynamic complications. We report a case of an individual in whom both transthoracic and transesophageal echocardiography demonstrated a posteriorly directed eccentric jet of severe mitral regurgitation due to a flail anterior mitral valve leaflet with presumed anterior papillary muscle rupture. Intraoperative findings confirmed rupture of the postero-medial papillary muscle attached via chords to the flail anterior mitral valve leaflet.

Case presentation
A 62 year-old female presented to hospital with a two day history of retrosternal chest discomfort, shortness of breath, nausea and diaphoresis. The patient was tachycardic, hypotensive, with a room air oxygen saturation of 83%. Jugular venous pressure was elevated at the angle of the jaw with prominent v wave. Initial cardiorespiratory examination was remarkable for an S3 with bibasilar crackles.

The complete blood count, electrolytes and liver function tests were within normal limits. The cardiac enzymes including troponon I and creatine kinase were elevated consistent with myocardial injury. The baseline electrocardiogram was consistent with an inferior ST-elevation myocardial infarction. Chest x-ray demonstrated pulmonary vascular redistribution.

After failed thrombolytics, the patient's cardiac catheterization revealed a distally occluded right coronary artery, not amenable to percutaneous coronary intervention. An intra-aortic balloon pump was inserted and she was transferred to the intensive care unit where urgent transthoracic echocardiography (TTE) revealed an eccentric, posteriorly directed jet of severe mitral regurgitation with a presumed rupture of the antero-lateral papillary muscle attached to the flail anterior mitral valve leaflet. This finding was confirmed by transesophageal echocardiography (TEE) (Figures 1 and 2)/>/>/>/>/>/>

Pages

References

  1. Himmelman RB, Kusumoto F, Oken K, Lee E, Cahalan MK, Shah PM, Schiller MB: The flail mitral valve: echocardiographic findings by precordial and trans-esophageal imaging and Doppler color flow mapping. J Am Coll Cardiol 1991, 17:272-279.
  2. Sochowski RA, Chan KL, Ascah KJ, Bedard P: Comparison of accuracy of transesophageal versus transthoracic echocardiography for the detection of mitral valve prolapse with ruptured chordae tendinae (flail mitral leaflet). Am J Cardiol 1991, 67:1251-1255.
  3. Hozumi T, Yoshikawa J, Yoshida K, Yamaura Y, Akasaka T, Shakudo M: Direct visualization of ruptured choradae tendinae by transesophageal two-dimensional echocardiography. J Am Coll Cardiol 1990, 16:1325-1319.
  4. Schluter M, Kremer P, Hanrath P: Transesophageal 2-D echocardiographic feature of flail mitral leaflet due to ruptured chordae tendinae. Am Heart J 1984, 108:609-610.
  5. Enriquez-Sarano M, Freeman WK, Tribouilloy CM, Orszulak TA, Khanderia BK, Seward JB, Bailey KR, Tajik AJ: Functional anatomy of mitral regurgitation: accuracy and outcome implication of transesophageal echocardiography. J Am Coll Cardiol 1999, 34:1129-1136.
  6. Colombo PC, Wu RH, Weiner S, Marinaccio M, Brofferio A, Banchs J, Malla S, Frater R, Shirani J, Nanna M: Value of quantitative analysis of mitral regurgitation jet eccentricity by color flow doppler for identification of flail leaflet. Am J Cardiol 2001, 88:534-540.