Where is papillary muscle

Sign in with Facebook. Sign in with Apple. Description The papillary muscles are muscles located in the ventricles of the heart. This definition incorporates text from the wikipedia website - Wikipedia: The free encyclopedia.

FL: Wikimedia Foundation, Inc. Subscribe now Discover our subscription plans Subscribe. Manage cookies Accept. Cookie settings. Essential technical cookies Description. Analytics cookies Description. Function: Prevent prolapse of the tricuspid valve leaflets during ventricular systole. Importance in cardiovascular diseases: Tricuspid regurgitation can be the result of papillary dysfunction or chordate rupture. Importance in device delivery: The papillary muscles and sub-valvular apparatus of the tricuspid can complicate the implantation of pacing leads into the right ventricular apex.

Go to the U of M home page. While some of these variations are benign, others are associated with significant morbidity. Papillary muscle dysfunction may result in mitral regurgitation, whereas papillary muscle rupture can be fatal if untreated. Cardiovascular magnetic resonance CMR is a modality well suited to the evaluation of papillary muscles, offering good spatial and temporal resolution, inherent soft tissue contrast, and lack of ionizing radiation.

There is only limited information regarding papillary muscles and its imaging in the literature. In this review, we discuss the role of CMR in the evaluation of normal and variant papillary muscle anatomy and in cases of papillary muscle abnormalities. The AL papillary muscle usually originates between the anterolateral and inferolateral walls, whereas the PM muscle originates near the attachment of the inferior wall to the septum Fig.

However, recent cross-sectional studies [ 3 ] have shown that most papillary muscles do not attach directly to the LV wall but instead attach to a network of trabeculae carneae, elongated strands of muscles lining the LV that attach to the solid portion of the LV wall [ 3 ]. Each papillary muscle has a major trunk containing approximately six projections or heads Fig. The papillary muscle head contains approximately 12 chordae tendinae connective tissue strands , each of which subdivides into two secondary chordae tendinae, which subdivide into two or three tertiary chordae tendinae.

Ultimately, each individual papillary muscle is affiliated with an average of 62 chordae. The chordae tendinae are attached to the tips of both mitral valve leaflets; hence, damage to one papillary muscle may affect both leaflets [ 4 ]. Normal anatomy of papillary muscles. The papillary muscles originate from the free wall of the LV attached to trabecula carnea. The papillary muscles give rise to multiple chordae tendinae blue , which attach to the mitral valve yellow.

The papillary muscles are the last portion of the heart to be perfused and are therefore are at high risk for ischemia [ 4 ]. Papillary muscles are supplied by channels that originate from the epicardial vessels that extend radially inward and supply in a segmental distribution i. The papillary muscles play an important role in mitral valve function. During systole, the papillary muscles contract before LV wall contraction [ 7 ], which results in apposition of the mitral valve leaflets, limiting the retrograde flow of blood from the LV back into the left atrium.

If an ectopic ventricular beat results in contraction of the LV wall before the papillary muscles, an element of mitral regurgitation will be present. Echocardiography is the first-line imaging modality used in the evaluation of cardiac abnormalities, including papillary muscles. Echocardiography allows for real time cine depiction of papillary muscle anatomy and function. This is obtained through a combination of 2D and 3D grey scale imaging for morphologic deepiction, with Doppler imaging providing additional hemodynamic insights.

Limitations of echocardiogram include operator dependence, limited soft tissue contrast, and limited field-of-view in a range of scenarios based upon patient anatomy COPD, obesity, narrow rib spacing , mobility, as well as post operative status with overlying hardware and bandages [ 10 ].

Computed tomography CT can be used in the evaluation of papillary muscle as well as other components of mitral valve apparatus. The high isotropic spatial resolution of CT allows exquisite morphological delineation and accurate measurement, which is essential for surgical and interventional techniques.

With retrospective ECG-gating, dynamic evaluation of the papillary muscles and quantification of ventricular function can be performed, however there is limited assessment of flow dynamics. While CT imaging is associated with ionizing radiation, this can be minimized with dose reduction strategies such as tube current modulation, as well as lower tube voltage and current settings [ 11 , 12 ]. CMR is well suited to the evaluation of papillary muscles because of its good spatial and temporal resolution, wide field-of-view, and multi-planar imaging capabilities.

CMR has high intrinsic soft tissue contrast that can be amplified with gadolinium-based contrast agents, which may lead to improved tissue characterization. A balanced steady-state free precession b-SSFP sequence is used to evaluate the anatomy and function of papillary muscles, ventricles, and valves.

Dynamic evaluation of papillary muscle contraction as well as measurement of muscle thickness and mass can be performed [ 13 ]. Novel 3D-cine-SSFP sequences enable 4D reconstruction, which allows for dynamic evaluation of papillary muscle motion in any plane.

LGE is useful in cases of cardiomyopathy, infarction, and masses. T1- and T2-weighted dark blood sequences with and without fat saturation are useful to in characterization of masses in papillary muscles. Parametric techniques, such as T1, T2, and extracellular volume ECV mapping are also useful in tissue characterization and quantification. Papillary muscles have the same signal intensity as the myocardium in all sequences: intermediate on T1-weighted, T2-weighted, and b-SSFP sequences.

Early and late contrast enhancement patterns are also similar to those of normal myocardium. The axis of the papillary muscles is oriented parallel to the axis of the LV Fig.

The thickness of the papillary muscles is approximately equal to the thickness of the septal or left ventricular free wall; however, the AL muscle tends to be slightly thicker than the PM muscle. Papillary muscle mass measured in end-diastole Fig.

Papillary muscle mass accounts for 8. Papillary muscle mass also correlates with body surface area, but there is weak or no correlation with age, body mass index, weight, and height [ 16 , 17 , 18 , 19 ].

MRI appearances of normal papillary muscles. The papillary muscles have been contoured blue in end-diastolic image to derive papillary muscle mass. The endocardial green and epicardial yellow contours are also seen. There is significant variability in papillary muscle morphology Fig.

Papillary muscles can be categorized by the number of muscle heads and then subcategorized depending on whether the heads share a common basal segment or have unique basal segments [ 20 ]. Typically, the AL muscle has a single major muscle group, whereas the PM muscle contains two or three major muscle groups [ 4 ]. When multiple muscle groups are present, they may share a common origin or may have separate origins.

Although many of these variants are considered normal and incidental, some papillary muscle variants result in functional deficits contributing to complications such as left ventricular outflow obstruction. The significant variations include anomalous insertion, accessory muscles, antero-apical displacement, double bifid morphology, and hypermobile muscles, which are discussed in detail in the section on obstructive lesions. Papillary muscle variations.

Parachute mitral valve is a rare congenital anomaly in which all of the chordae tendinae originate from a single papillary muscle [ 21 , 22 ] Fig. The common insertion is into the PM muscle in three fourths of cases. Because of the abnormal chordal attachment, the mitral valve is shaped like a funnel in these cases.

The chordae are short and thickened, limiting the movement of the mitral valve cusps and resulting in stenosis. Parachute mitral valve. The chordae tendinae blue originate from a single papillary muscle P. Parachute mitral valve is the most common cause of isolated mitral stenosis in children [ 23 ]. Mitral incompetency or normal valve function can also be seen.

Parachute mitral valve is also seen in association with other congenital cardiac abnormalities, especially ventricular septal defects, valvular aortic stenosis, pulmonic stenosis, and patent ductus arteriosus [ 24 ]. Although this condition usually presents during childhood, milder lesions may present in adults as dyspnea, overt cardiac failure, pulmonary hypertension, and recurrent infections.

On CMR images of parachute mitral valve, all of the chordae tendinae arising from the mitral valve leaflets attach to a single papillary muscle Fig. In diastole, a jet of dephasing spins is often seen passing from the left atrium to the LV due to mitral valvular stenosis.

Occasionally, mitral incompetence may also be seen. In severe cases, mitral valvotomy or mitral valve replacement may be necessary, particularly in cases of subaortic stenosis. Findings such as LV hypoplasia and atrial septal defects are associated with poorer postoperative outcomes [ 25 ]. Parachute-like asymmetric mitral valve is more common than parachute mitral valve Fig.

In individuals with this condition, there are two papillary muscles present. One of the papillary muscles is normal and the other is elongated with its tip attached to the mitral valve.

The abnormal papillary muscle has few or no chords, resulting in an eccentric mitral valve orifice [ 25 ]. It is controversial whether parachute-like asymmetric mitral valve should be considered a variant of parachute mitral valve, as their developmental etiologies differ [ 25 ]. Parachute-like asymmetric mitral valve. On CMR images of the parachute-like mitral valve, both of the papillary muscles are present, but one is elongated and located asymmetrically higher in the LV Fig.

The attachment of the papillary muscles at the mitral valve is also asymmetric, resulting in an asymmetric mitral valve orifice Additional file 2 : Movie S2. Unlike true parachute mitral valves, parachute-like asymmetric mitral valves may be asymptomatic. However, case reports have suggested an increased propensity toward the development of infective endocarditis in patients with this condition because of turbulent flow across the abnormal valve [ 26 ].

Nearly two thirds of patients present with all four lesions, but the presence of any three of these lesions is sufficient for the diagnosis of Shone complex. Aortic coarctation can be easily identified on CMR as a focal narrowing of the thoracic aorta best demonstrated on sagittal or left anterior oblique views Fig.

A supra-valvular mitral ring appears as a membrane within the left atrium above the mitral valve orifice. This ring may attach to the mitral valve and restrict its mobility or may directly obstruct blood flow through the mitral valve [ 29 ].

Subaortic stenosis in Shone complex can take two forms, muscular Fig. Surgical management of this condition includes correction of the coarctation, resection of the lesion causing subaortic stenosis, and possible LV outflow tract LVOT reconstruction or bypass.

When applicable, associated lesions such as ventricular septal defects may also require repair [ 27 ]. Shone complex. There is a wide communication between this abnormal outpouching and the cardiac chamber. Most cases are congenital due to mal-development of the myocardial intra-trabecular sinusoids; this condition can also be associated with endocardial fibroelastosis or hypertrophic cardiomyopathy HCM [ 32 ].

A double-chambered LV is asymptomatic and often an incidental finding. This band extends across the LV, connecting the papillary muscles. Dynamic imaging will demonstrate that the double-chambered LV has a normal contraction in systole, thus distinguishing this entity from an aneurysm [ 33 ]. Surgical treatment can be performed if needed typically when this condition is associated with other cardiac abnormalities.

LV non-compaction is a type of cardiomyopathy in which there is an exaggerated component of non-compacted LV myocardium. This is caused by persistence of primitive embryonal cardiac sinusoids beyond fetal life, with a failure to mature to compacted myocardium. However, a more recent study [ 35 ] demonstrated the lack of specificity of this finding. Additional findings such as an abrupt transition between normal and thinned myocardium in the non-compacted area may increase the specificity of this technique.

Complications of LV non-compaction include ventricular arrhythmia, thromboembolism, and ventricular dysfunction. Papillary muscle thickening can be caused by hypertrophy or infiltrative disorders e. Common causes of hypertrophy include systemic hypertension and HCM. In cases of hypertension, there is proportional hypertrophy of the papillary muscles increased thickness and mass along with concentric LV hypertrophy [ 4 ] Fig.

Proportionate thickening is also typically seen in cases of the concentric type of HCM. Papillary muscle hypertrophy. Short-axis cine-SSFP image in a patient with systemic hypertension shows hypertrophy of the papillary muscles curved arrow , which is proportionate to the concentric LV hypertrophy straight arrows.

HCM represents a diverse collection of abnormalities. The most common phenotype of HCM is asymmetric septal hypertrophy, followed by mid-ventricular, apical, concentric, and mass-like subtypes. LGE due to interstitial fibrosis may also be seen in hypertrophied and non-hypertrophied segments, typically in a mid-myocardial, patchy distribution, and often at right ventricle RV insertion points Fig.

LGE is associated with worse symptoms, more severe cardiac dysfunction, and the development of ventricular dysrhythmias [ 37 , 38 ]. Hypertrophic cardiomyopathy. The posteromedial papillary muscle also shows patchy areas of delayed enhancement white arrow. The hypertrophy of papillary muscles correlates with LV wall thickness and myocardial mass [ 2 ], and the papillary muscle mass index is also weakly correlated with the magnitude of outflow gradient [ 2 ].

These findings suggest that papillary muscle hypertrophy may not be caused by a primary genetic abnormality alone but may also be secondary to LV pressure overload from LV obstruction [ 39 ]. The distance between the papillary muscle and the septum is also a point of interest in patients with HCM, as this distance was noted to be smaller in patients with obstruction [ 39 ].

In addition, patients with HCM also tend to have a larger number of papillary muscles 2. In this condition, the papillary muscles are hypertrophied but the rest of the left ventricular myocardium is spared [ 39 , 40 ].

These patients present with angina, dyspnea, syncope, and sudden cardiac death [ 40 ]. On CMR images, hypertrophic papillary muscles may demonstrate dynamic mid-cavity obstruction and flow acceleration within the LV Fig. The inexperienced viewer may easily overlook a papillary muscle abnormality in the absence of LVH and mistake a case of HCM for a normal examination. Solitary papillary muscle hypertrophy.

In one type of anomalous insertion, the papillary muscles bypass the usual connection of the chordae tendinae and insert directly into the mitral valves Fig. In another type, the chordae tendinae insert into the mid or basal portions of the mitral leaflets instead of into the tips Fig. When the papillary muscles attach in an abnormal fashion, they occupy an atypical location within the LV, which may result in dynamic mid-cavity obstruction.

Anomalous papillary muscle insertion. Anomalous direct insertion of the anterolateral papillary muscle to the anterior mitral leaflet arrow without intervening chorda tendinae.

Illustration of anomalous insertion of the anterolateral papillary muscle A into the mid-portion of anterior mitral leaflet arrow , which results in leaflet slack and narrowing of the LVOT.

The apical-basal muscle bundle refers to an accessory papillary muscle or muscle bundle that extends from the LV apex and inserts into the basal myocardium without insertion into the mitral leaflet.

On CMR, an accessory papillary muscle is best visualized on the 3-chamber view as a single band of muscle extending from the LV apex through the LV cavity to the basal anteroseptum or anterior wall Additional file 8 : Movie S8.

This accessory muscle is typically not associated with LVOT obstruction and is independent of septal thickness. However, it is an important morphological marker for HCM and an independent and primary component of HCM disease expression; this muscle may be useful for screening family members for HCM [ 42 ]. This displacement results in leaflet slack; the mitral valve subsequently moves toward the septum, resulting in systolic anterior motion of the mitral valve and causing LVOT obstruction [ 44 ].

This abnormality is associated with higher LVOT gradients and systolic anterior motion of the anterior mitral valve leaflet , independent of septal thickness or medical therapy Fig. On CMR images of patients with this condition, the base of the papillary muscle is displaced anteriorly in relation to the ventricular septum and distally in 2- or 4-chamber views Fig.

The papillary muscle is also visible in the distal-most apical short-axis image Fig. Anteroapical displacement. Bifid papillary muscles are characterized by the presence of more than one muscle head.

This may be seen in one or both papillary muscle groups double bifid morphology Fig. Bifid papillary muscles are often hypermobile [ 45 ] and may be associated with premature ventricular complexes resulting in bigeminy, even in the absence of obstruction [ 46 ].