Quantification of mitral papillary muscle function using speckle tracking echocardiography in apparently healthy population

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Cardiac mitral papillary muscle is a structure that has been long ignored. Recently, growing evidence from case reports showed an important role in the pathophysiology of many cardiac pathologies such as hypertrophic cardiomyopathy and dilated cardiomyopathy. To our knowledge, there isn’t any approved standard technique nor any methodological descriptive study of papillary muscle function in the apparently healthy population. Purpose To investigate mitral papillary muscle function in apparently healthy population by speckle tracking echocardiography (STE) using a proposed standard method. Methods We prospectively performed standard transthoracic echocardiography(TTE) in an apparently healthy cohort. Posterior mitral papillary muscle(PPM) was visualized on a modified three chamber view. The anterior papillary muscle(APM) was visualized on a modified 4 chamber view. To measure the value of the papillary muscles longitudinal strain, tracing of PPM and APM was done by a drag and click technique using an ECHOPAC software. Good quality tracing was ensured before approving the measurements. Each papillary muscle was divided into three segments by the software. 2D longitudinal strain curves of each papillary muscle consisted in 3 solid lines of the three segments and a dashed line that represented the mean longitudinal strain of the whole papillary muscle. This latter line was used to derive peak values, post systolic shortening (PSS) and systolic stretch (SS). Time of aortic valve closure was determined on the LV outflow pulsed doppler. Results Our study included 57 apparently healthy individuals between May 2021 and August 2021. Two patients were excluded due to lack of echogenicity. 71.19% (n = 44) were male. Mean age was 36 ± 14 yrs. 15.7% (n = 9) had history of hypertension and 7% (n = 4) were diabetic. 3.5% (n = 2) had history of stroke. 91.2% (n= 52) had functional status NYHA class I, 12.2% (n = 7) had functional status class II. All of our cohort had a left ventricular ejection fraction (LVEF) above 55%, did not have diastolic dysfunction and were on sinus rhythm. PPM peak strain value was -15.49 ±4.69 %. PSS was present in 98.2% (n = 56) and SS in 62.5%(n = 36) of cases. Anterior papillary muscle (APM) had a peak strain value of -15.61 ± 3.66, PSS was present in 78.5% (n = 45) and SS in 51.7% (n = 29). Conclusion Mitral papillary muscles echocardiographic study is feasible in routine scans with modified apical views. Post systolic shortening and systolic stretch are present in the majority of individuals. Abstract Figure. posterior papillary muscle strain curve Abstract Figure. anterior papillary muscle strain curve