Papillary Muscle Function Does Not Predict Mitral Regurgitation in Patients with Normal Left Ventricular Systolic Function: A Transesophageal Echocardiographic Study

Abstract

Objective: To evaluate LV papillary muscles (PM) function using transesophageal echocardiography (TEE), and to determine the relationship between PM function and mitral regurgitation in patients with normal left ventricular sys-tolic function. Design: TEE examinations were prospectively performed. End diastolic and end systolic PM lengths were obtained from the transgastric long axis views and fractional systolic shortening (FS) was calculated. LV ejection fraction was determined using modified Simpson rule and mitral regurgitation was determined using regurgitant jet area by color flow. Setting: Tertiary Center. Patients: 85 consecutive adult patients (51 with mitral regurgitation and 34 without) with normal LV chamber dimensions and LV systolic function, meeting enrollment criteria. Results: The % FS in patients with mitral regurgitation was 21.7 ± 3.6% for anterior PM (APM) and 18.7 ± 4.6% for posterior PM (PPM). In those without mitral regurgitation, the values were as follows; 22.6 ± 5.4% (APM) and 19.5 ± 3.8% (PPM). In a subgroup of patients with severe mitral regurgitation (n = 23), the values for PM FS were 20.3 ± 6.8 (APM) and 18.4 ± 6.9 % (PPM). There was no statistically significant difference in PM fractional shortening between the groups. Anterior papillary muscle length was longer in those patients with mitral regurgitation compared to those without [(End-diastolic length (cm): 3.38 ± 0.61 v 2.88 ± 0.47(p: 0.008) and end-systolic length of 2.46 ± 0.51 v 2.17 ± 0.33 (p: 0.04)]. These differences are more pronounced in those with severe mitral regurgitation (p: 0.002 and 0.004 for EDL and ESL respectively. Conclusion: In patients with normal LVEF, PM contraction is similar in those with and without MR. In patients with MR however, anterior PM length (ED & ES) is significantly increased. Our data suggests that in patients with normal LVEF, PM dysfunction appears to play no significant role in the causation of MR. Anterior papillary muscle length however, appears to be a major determinant of mitral regurgitation in such patients

Prognostic Relevance of Papillary Muscle Infarction in Reperfused Infarction as Visualized by Cardiovascular Magnetic Resonance

“…In line with previous studies, PapMI was a nonsignificant predictor of the presence and severity of MR. 4 There is strong experimental evidence that isolated papillary muscle dysfunction in an adequately contractile ventricle is not associated with significant MR. 10 Furthermore, several human studies using echocardiography found no correlation between mild MR and papillary muscle dysfunction. 11,12 Consequently, echocardiography and CMR studies, including our study, have unequivocally demonstrated that PapMI is not obligatorily associated with ischemic MR.…”

Papillary muscles of left ventricle—Morphological variations and it’s clinical relevance

“…Loss of this contractile action results from myocardial infarction with subsequence papillary muscle fibrosis or ischemia 4 . But previous studies5, 6 delineated that there is minimal or no correlation between papillary muscle dysfunction and mitral regurgitation, especially in those patients where left ventricular chamber size and function is normal.…”

Papillary Muscle Free Strain in Patients with Severe Degenerative and Functional Mitral Regurgitation

“…The impairment of the subvalvular apparatus is detrimental to the left ventricular systolic function and mitral regurgitation. 3 , 4 Papillary muscle dysfunction has previously been shown as a mechanical cause of mitral regurgitation in patients with functional mitral regurgitation (FMR) in some studies, but, in some others, no correlation was found between mitral regurgitation and papillary muscle dysfunction and even an attenuating effect of papillary muscle dysfunction was reported in most studies. 2 , 3 , 5 - 8 In experimental studies, under the range of normal loading and inotropic conditions, papillary muscle contraction normally follows the general characteristics of left ventricular contraction, 4 but ischemia or stunning may disrupt this course.…”

“… 3 , 4 Papillary muscle dysfunction has previously been shown as a mechanical cause of mitral regurgitation in patients with functional mitral regurgitation (FMR) in some studies, but, in some others, no correlation was found between mitral regurgitation and papillary muscle dysfunction and even an attenuating effect of papillary muscle dysfunction was reported in most studies. 2 , 3 , 5 - 8 In experimental studies, under the range of normal loading and inotropic conditions, papillary muscle contraction normally follows the general characteristics of left ventricular contraction, 4 but ischemia or stunning may disrupt this course. It is reported that in ischemic mitral regurgitation, diminished papillary muscle shortening, which is termed as papillary muscle dysfunction, paradoxically decreases the degree of MR. 5 , 7 In patients with normal LV function and MR, fractional shortening has been shown to be normal, similarly to patients with mild or more severe MR. 3 In patients with degenerative mitral regurgitation (DMR), there is no sufficient knowledge about the role of papillary muscle (PM) dysfunction.…”

“… 2 , 3 , 5 - 8 In experimental studies, under the range of normal loading and inotropic conditions, papillary muscle contraction normally follows the general characteristics of left ventricular contraction, 4 but ischemia or stunning may disrupt this course. It is reported that in ischemic mitral regurgitation, diminished papillary muscle shortening, which is termed as papillary muscle dysfunction, paradoxically decreases the degree of MR. 5 , 7 In patients with normal LV function and MR, fractional shortening has been shown to be normal, similarly to patients with mild or more severe MR. 3 In patients with degenerative mitral regurgitation (DMR), there is no sufficient knowledge about the role of papillary muscle (PM) dysfunction. The role of papillary muscle function in severe MR and the method of choice to evaluate PM are still controversial.…”