Anomalous Papillary Muscle Insertion Research Articles

Anomalous papillary muscle insertion into the mitral valve leaflet in hypertrophic obstructive cardiomyopathy: a lip nevus sign in echocardiography.

Anomalous papillary muscle (APM) insertion into the mitral valve leaflet is rare but clinically important in hypertrophic obstructive cardiomyopathy (HOCM). In this study, we report the detection rate of APM insertion into the mitral valve using preoperative imaging modalities and the surgical outcomes of the patients. By retrospectively reviewing the clinical records of patients with HOCM who underwent surgical treatment by a single operation group at our center from January 2020 to June 2023, patients with APM insertion into the mitral valve leaflet were identified. Baseline data, image characteristics, and surgical outcomes were analyzed. The incidence of APM insertion into the mitral valve leaflet was 5.1% (8/157). The insertion site was located at A3 in six cases, which was more common than at A2 (n = 2). Preoperative echocardiography was used to identify two patients (25%) with APM insertion. We observed a particular echocardiographic feature for APM in HOCM patients, which was noted as a "lip nevus sign", with a higher detection rate (62.5%). All patients successfully underwent septal myectomy with concomitant APM excision or mitral valve replacement via the transaortic (n = 5) or transmitral (n = 3) approach. The mean age was 49.0 ± 17.4 years and seven patients (87.5%) were female. Interventricular septum thickness (17.0 mm vs. 13.3 mm, P = 0.012) and left ventricular outflow gradient (117.5 mmHg vs. 7.5 mmHg, P = 0.012) were significantly decreased after surgery. Residual outflow obstruction, systolic anterior motion, and ≥3+ mitral regurgitation were negative. During the follow-up of 26.2 ± 12.2 months, there were no reported operations, adverse events, mitral regurgitation aggravations, recurrences of outflow obstruction, or instances of SAM. Papillary muscles inserted into the mitral valve leaflet are a subtype of subvalvular malformation in HOCM that requires surgical correction. The lip nevus sign on echocardiography is a characteristic of APM insertion in HOCM and may improve the preoperative detection rate. Adequate myectomy with anomalous papillary muscle excision has achieved good results in reducing the outflow gradient and eliminating mitral regurgitation, with good outcomes at short-to-intermediate follow-up.

Is Congenital Muscular Mitral-Aortic Discontinuity Another Feature of Obstructive Hypertrophic Cardiomyopathy? A Pathology Validation Study

Hypertrophic cardiomyopathy (HCM) is an inherited myocardial disease at risk of sudden cardiac death and heart failure, even requiring heart transplantation. A “muscular mitral-aortic discontinuity” has been reported during surgery in the obstructive form. We aimed to validate these findings through pathological analysis of HCM heart specimens from the cardiovascular pathology tissue registry. Hearts with septal asymmetric HCM from sudden cardiac death, other causes of death, or heart transplantation were included. Sex-matched and age-matched patients without HCM served as controls. Gross and histologic analysis of the mitral valve (MV) apparatus and the mitral-aortic continuity were performed. Thirty HCM hearts (median age, 29.5 years; 15 men) and 30 controls (median age, 30.5 years; 15 men) were studied. In HCM hearts, a septal bulging was present in 80%, an endocardial fibrous plaque in 63%, a thickening of the anterior MV leaflet in 56.7%, and an anomalous insertion of papillary muscle in 10%. All cases but 1 (97%) revealed a myocardial layer overlapping the mitral-aortic fibrous continuity on the posterior side, corresponding to the left atrial myocardium. A negative correlation between the length of this myocardial layer and the age and the anterior MV leaflet length was found. The length did not differ between HCM and controls.Pathologic study of obstructive HCM hearts does not confirm the existence of a "muscular mitral-aortic discontinuity". An extension of left atrial myocardium, overlapping posteriorly the intervalvular fibrosa, is rather visible, and its length decreases with age, possibly as a consequence of left atrial remodeling. Our study highlights the fundamental role of thorough gross examination and the value of organ retention for further analysis in order to validate new surgical and imaging findings.

Anomalous papillary muscle insertion into mitral valve leaflet: Autopsy study and implications

Anomalous papillary muscle (APM) insertion into the anterior mitral valve leaflet is often associated with hypertrophic cardiomyopathy (HCM) but is reported in other cases as a rare finding. Mere presence does not strictly imply hemodynamic disturbance, and several types exist, with various impacts on left ventricular outflow tract (LVOT) obstruction. The interpretation of isolated anomaly is challenging at autopsy because significant LVOT obstruction is dynamic. We analyzed autopsy cases with APM regarding the site of PM insertion and origin, number of PM bellies, anomalous insertions, heart weight, left ventricle (LV) thickness, LV endocardial fibrosis, subjects' age, sex, cause, and manner of death. A total of 20 cases were identified. Fourteen were identified incidentally, while in 670 systematically examined hearts, the APM was identified in six cases, indicating a prevalence of 0.9%. In eight cases, the manner of death was natural (one case with HCM), and in 12 non-natural. Type II anomaly of PM was most frequent (n=8), followed by Type III (n=7) and Type I (n=5). Subjects who died of natural causes were significantly older and had heavier hearts (median 455 g vs. 330 g; p < 0.05) without difference in LV thickness (median 16 mm vs. 15 mm; p > 0.05). Histology performed in four cases showed a pattern of direct insertion of cardiomyocytes into the leaflet's thick fibrous tissue with a narrow overlapping zone. The APM is rare, can be easily overlooked, and does not imply significant pathology per se. We discussed proper assessment of the significance of this anomaly at autopsy.

Abstract 11196: Germline Mutation in Plakophilin 2 and Associated Hypertrophic Cardiomyopathy: Clinical Debate of Nascent Pleomorphism and Pleotropism

Introduction: Arrhythmogenic cardiomyopathy(ACM) is often not seen until adolescence or early childhood. Electric abnormalities usually precede the structural remodeling visible on cardiac imaging. Clinical case: 31-year-old male with asthma and hypertension presented to the ED with palpitations and was in atrial fibrillation with rapid ventricular response. He was treated with diltiazem and converted to sinus rhythm. TTE performed showed basal septal hypertrophy with hypercontractile LV. He was discharged on beta-blocker and anticoagulation. Few days after, he reported lightheadedness and syncopal spells after starting on beta-blocker therapy, and orthostatic by nature. ECG revealed sinus rhythm, left ventricular hypertrophy and inferolateral deep T wave inversions. Family history was revealing for HCM in father and grandmother, but no genetic conditions or sudden cardiac deaths. Stress TTE with diltiazem use showed no LVOT obstruction at rest or after exercise. Cardiac MRI revealed asymmetric basal septal hypertrophy with max thickness of 1.5 cm. Dynamic LVOT obstruction was seen with anomalous insertion of papillary muscle into mid-anterior portion of anterior mitral leaflet. LV was hypercontractile with EF 85%, and no evidence of fibrosis. RV was normal in size/function without abnormal wall motion. Holter monitoring was unremarkable. Cardiomyopathy/arrhythmia multigene panel testing surprisingly showed a heterozygous plakophilin-2(PKP2) pathogenic germline mutation c.1689-1G&gt;C, pathogenic for ARVC. Conclusion: Based on current guidelines, he would not have ACM and begs the question of management in patients with positive ACM genetics, but no ACM-related disease expression. The underlining question would be the clinical significance and evolution of such detected mutations, and given the current paucity in evidence, we share your enthusiasm in learning more about this patient’s future clinical trajectory.

Surgery for Anomalous Papillary Muscle Directly Into the Anterior Mitral Leaflet

The anomalous insertion of papillary muscle directly into the anterior mitral leaflet is a rare congenital anomaly concomitant with hypertrophic cardiomyopathy. We herein report our surgical technique, which is designed to relieve left ventricular obstruction and preserve the mitral valve and subvalvular apparatus. Among 38 patients who underwent septal myectomy from 2007 to 2020, 4 had an anomalous mitral subvalvular apparatus with papillary muscle with direct insertion into the anterior mitral leaflets. In all cases, mitral valve repair was accomplished with excision and reconstruction of all anomalous papillary muscles, concomitant with septal myectomy. In another 34 patients, 20 cases needed mitral valve repair with regard to systolic anterior motion by hypertrophic cardiomyopathy. The comparison study was conducted between the anomalous papillary muscle group (group A) and the others (group B). There was no early or late death in group A, and there were 3 early deaths and 2 late deaths in group B. The mean peak gradient in the left ventricle was significantly decreased in both groups. Mitral valve regurgitation grade was also significantly decreased from 3 to 0.5 without valve replacement in group A, and from 2 to 0.6 in group B. Six patients needed mitral valve replacement because of the thickness of anterior mitral leaflet in group B. Hypertrophic obstructive cardiomyopathy associated with the anomalous insertion of papillary muscle can be successfully treated without mitral valve replacement. Excision and reconstruction with the anomalous papillary muscle seems to be a feasible operation to reduce mitral regurgitation and relieve outflow tract obstruction.

Anomalous papillary muscle insertion in hypertrophic cardiomyopathy.

Half of the patients with hypertrophic cardiomyopathy (HCM) have left ventricular outflow (LVOT) obstruction as a result of systolic anterior motion of the mitral valve. A 51-year-old man with HCM presented with exertional dyspnoea and syncope refractory to medical therapy found to have an LVOT gradient of 27 mmHg at …

Role of noninvasive imaging modalities to better understand the mechanism of left ventricular outflow tract obstruction and tailored lesion-specific treatment options.

Left ventricular outflow tract obstruction (LVOTO) has important prognostic implications in patients with hypertrophic cardiomyopathy (HCM). Echocardiography provides critical information to establish LVOTO as a unique feature of HCM by demonstrating heterogeneity of hypertrophy patterns and the systolic anterior motion of mitral leaflets, resulting in mitral-septal contact. Currently, 2 treatment strategies are available for reduction of muscle mass to relieve LVOTO: surgical myectomy and percutaneous alcohol septal ablation. Both focus on mechanical removal of the hypertrophied septum. However, this alone is not the best approach to abolishing LVOTO, because recurrence is common and requires additional septal reduction. Recent 3-dimensional in vivo measurements and other noninvasive cardiac imaging modalities have confirmed primary alterations of the mitral valvular apparatus, including leaflet elongation with increased surface area and abnormal displacement of papillary muscles. More importantly, these extra-myocardial changes appear to be independent factors associated with the development of LVOTO. Other important anatomical changes include anomalous papillary muscle insertion into the anterior mitral leaflet and midventricular obstruction because of apposition of the hypertrophied mid-septum and the papillary muscle. Thus, the myocardium is not the only tissue affected in patients with HCM. A tailored approach to correcting primary changes of the mitral valvular apparatus and hypertrophy pattern based on a comprehensive evaluation using noninvasive imaging modalities is necessary to improve long-term outcomes.

Anomalous insertion of papillary muscle into mitral leaflet in patients with hypertrophic obstructive cardiomyopathy

Anomalous insertion of papillary muscle into mitral leaflet in patients with hypertrophic obstructive cardiomyopathy

Hypertrophic Cardiomyopathy

Hypertrophic Cardiomyopathy

Left Ventricular Outflow Tract Obstruction Due to Anomalous Insertion of Papillary Muscle

A 56-year-old man who complained of quadrantic hemianopsia was admitted to determine its etiology. Cerebral angiography revealed no organic stenosis. Echocardiography showed clear direct continuity between a hypertrophied anterolateral papillary muscle and the anterior mitral leaflet, and the left ventricular (LV) outflow tract (LVOT) was narrowed by the presence of an accessory papillary muscle. The LVOT obstruction caused an intra-LV pressure overload that resulted in LV concentric hypertrophy. Arrhythmia, such as paroxysmal atrial fibrillation (PAF), was thought to have caused a cerebral embolism. Mitral valve replacement (MVR), septal myectomy, and myectomy of the abnormal papillary muscle were performed, and complete release of the LVOT obstruction was accomplished. Anomalous insertion of papillary muscle is a rare cause of LVOT obstruction. Echocardiography was useful in identifying the papillary muscle malformation, and surgery was completely curative.

Mitral valve–sparing operation in subaortic stenosis caused by anomalous papillary muscle and discrete subaortic stenosis

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Echocardiographic Findings and Clinical Manifestations of Hypertrophic Cardiomyopathy: Including 3 Cases of Anomalous Insertion of Papillary Muscle

Echocardiographic Findings and Clinical Manifestations of Hypertrophic Cardiomyopathy: Including 3 Cases of Anomalous Insertion of Papillary Muscle

Anomalous insertion of papillary muscle directly into anterior mitral leaflet in hypertrophic cardiomyopathy. Significance in producing left ventricular outflow obstruction.

Obstruction to left ventricular outflow in hypertrophic cardiomyopathy (HCM) is usually due to systolic anterior motion of the mitral valve. Occurrence of structural mitral valve abnormalities in HCM and their significance in producing outflow obstruction (even in the absence of typical systolic anterior motion) has not been fully appreciated. Analysis of 78 mitral valves excised from patients with obstructive HCM showed that 10 (13%) had anomalous insertion of one or both left ventricular papillary muscles directly into the anterior mitral leaflet. This malformation was identified by echocardiography, which demonstrated direct continuity between the hypertrophied papillary muscle and mitral leaflet, resulting in a long rigid area of midcavity narrowing that appeared to be solely or largely responsible for outflow obstruction. Basal subaortic pressure gradients were large (70-150 mm Hg). Mitral valve replacement reduced the outflow gradient substantially to 0-15 mm Hg in four patients with postoperative cardiac catheterization. However, two other patients who underwent septal myotomy/myectomy had persistent symptoms and incomplete relief of obstruction (gradients 60 and 70 mm Hg) because of continued midcavity apposition of papillary muscle and ventricular septum. Anomalous papillary muscle insertion into anterior mitral leaflet represents a mechanism of obstruction to left ventricular outflow in patients with HCM and differs considerably from typical dynamic obstruction caused by mitral valve systolic anterior motion that occurs in many other patients with HCM. Recognition of this malformation emphasizes the diverse morphological expression of HCM and also has important clinical implications for patients requiring operation because the gradient is likely to persist even after adequate myotomy/myectomy; consequently, mitral valve replacement would appear to be the operation of choice in most such patients.

Anomalous Papillary Muscle Insertion Contributing to Obstruction in Discrete Subaortic Stenosis

A case of discrete subvalvular aortic stenosis with anomalous insertion of a papillary muscle to the base of the anterior mitral valve leaflet and continuous with the discrete subaortic stenosis is described. Two-dimensional echocardiographic and pathologic data showing the contribution of the anomalous papillary muscle to left ventricular outflow tract obstruction are presented.