Abnormal Papillary Muscle Research Articles

Moderate Mitral Regurgitation Secondary to Hammock Congenital Mitral Valve Disease

A 30-year-old woman with a history of systemic lupus erythematosus and hypothyroidism . She started with dyspnea on moderate exertion, orthopnea, and a sensation of palpitations an early systolic murmur of mitral regurgitation was found. Transthoracic and transesophageal echocardiography reported hammock congenital mitral valve disease as a cause of mitral regurgitation with impaired functional class, requiring surgical valve replacement. The mitral arcade, or hammock mitral valve, is a very rare entity, even more so in the adult population, with a reported prevalence of 0.5%. It is characterized by abnormal papillary muscles connected directly to the anterior mitral.

Obstructive hypertrophic cardiomyopathy: a review of new therapies.

Hypertrophic cardiomyopathy (HCM) is a phenotypically heterogeneous disease with a genetic basis and variable penetrance. The hallmarks of HCM include dynamic left ventricular outflow tract obstruction, typically caused by asymmetric septal hypertrophy. However, abnormal papillary muscle placement, abnormal mitral valve and subvalvular apparatusand apical hypertrophic forms have also been described. Typical medical treatment has been stagnant for decades, although there have been significant advances in surgical treatment of patients with obstructive HCM. Herein, we describe a new class of drugs targeting the specific pathophysiology of HCM.

Dark papillary muscles sign: a novel prognostic marker for cardiac magnetic resonance

Abstract Funding Acknowledgements Type of funding sources: None. Background the prognostic role of left ventricular (LV) papillary muscle abnormalities in patients with preserved LV systolic ejection fraction (LVEF) is unknown. Aim to evaluate the prevalence and the clinical and prognostic impact of papillary muscle abnormalities by CMR in patients with ventricular arrhythmias, preserved LVEF with no cardiac disease. Methods 391 patients with >500/24h premature ventricular complexes and/or with non-sustained ventricular tachycardia (NSVT), preserved LVEF and no cardiac disease, were enrolled. Different features of LV papillary muscles were considered: supernumerary muscles, papillary thickness, the attachment, late gadolinium enhancement (LGE). The end-systolic hypointensity was defined when its measured signal intensity (SI) was lower than the SI of the septum in early post-contrast cine CMR images. Dark-Paps was defined when both the main papillary muscles had systolic hypointensity. Mitral valve prolapse, mitral annular disjunction (MAD), myocardial LGE were considered. The outcome of hard cardiac events was define as a composite of cardiac death, resuscitated cardiac arrest, and appropriate implantable cardioverter defibrillator (ICD) shock, sustained ventricular tachycardia (lasting ≥30 s at ≥100 beats/min). Results Dark-Paps was found in 79 (20%) patients and was more frequent in females. It was associated with higher prevalence of mitral valve prolapse and MAD. During a median follow-up of 2534 days, 22 hard cardiac events occurred. At Kaplan-Meier curve (Figure) analysis patients with Dark-Paps were at higher risk of events than those without (p<0.0001). Dark-Paps was significantly associated with hard cardiac events in all the multivariate models performed. Dark-Paps improved prognostic estimation when added to NSVT (p = 0.0006), to LGE (p = 0.005) and to a model including NSVT+LGE (p = 0.014). Dark-Paps allowed a significant net reclassification when added to NSVT (NRI 0.30, p =0.03), to LGE (NRI 0.25, p =0.04), and to NSVT + LGE (NRI 0.32, p =0.02). Conclusions Dark-Paps sign could be considered a novel imaging prognostic marker in patients with ventricular arrhythmias and preserved ejection fraction.

The role of papillary muscle abnormalities in hypertrophic cardiomyopathy: a new paradigm shift?

The role of papillary muscle abnormalities in hypertrophic cardiomyopathy: a new paradigm shift?

Dark papillary muscles sign: a novel prognostic marker for cardiac magnetic resonance

ObjectivesThe prognostic role of left ventricular (LV) papillary muscle abnormalities in patients with preserved LV systolic ejection fraction (LVEF) is unknown. We sought to evaluate the prognosis role of LV papillary muscle abnormalities by CMR in patients with ventricular arrhythmias, preserved LVEF with no cardiac disease.MethodsA total of 391 patients with > 500/24 h premature ventricular complexes and/or with non-sustained ventricular tachycardia (NSVT), preserved LVEF, and no cardiac disease were enrolled. Different features of LV papillary muscles were considered: supernumerary muscles, papillary thickness, the attachment, late gadolinium enhancement (LGE). Dark-Paps was defined as end-systolic signal hypointensity of both papillary muscles in early post-contrast cine CMR images. Mitral valve prolapse, mitral annular disjunction (MAD), and myocardial LGE were considered.ResultsDark-Paps was found in 79 (20%) patients and was more frequent in females. It was associated with higher prevalence of mitral valve prolapse and MAD. During a median follow-up of 2534 days, 22 hard cardiac events occurred. At Kaplan-Meier curve analysis, patients with Dark-Paps were at higher risk of events than those without (p < 0.0001). Dark-Paps was significantly associated with hard cardiac events in all the multivariate models. Dark-Paps improved prognostic estimation when added to NSVT (p = 0.0006), to LGE (p = 0.005) and to a model including NSVT+LGE (p = 0.014). Dark-Paps allowed a significant net reclassification when added to NSVT (NRI 0.30, p = 0.03), to LGE (NRI 0.25, p = 0.04), and to NSVT + LGE (NRI 0.32, p = 0.02).ConclusionsIn LV papillary muscles, Dark-Paps is a novel prognostic marker in patients with ventricular arrhythmias and preserved ejection fraction.Key Points• Papillary muscle abnormalities are seen in patients with ventricular arrhythmias and preserved left ventricular ejection fraction.• Early post-contrast hypointensity of papillary muscles in end-systolic cine images (Dark-Paps) is a novel prognostic marker in patients with ventricular arrhythmias and preserved ejection fraction.• Dark-Paps had an additive prognostic role over late gadolinium enhancement and non-sustained ventricular tachycardia.

Effect analysis of myectomy guided by personalized three-dimensional reconstruction and printing in the treatment of obstructive hypertrophic cardiomyopathy

Objective: To examine the clinical efficacy of myectomy guided by personalized three-dimensional reconstruction and printing for patients with obstructive hypertrophic cardiomyopathy. Methods: The clinical data of 28 patients with obstructive hypertrophic cardiomyopathy, who underwent septal myectomy guided by personalized three-dimensional reconstruction and printing in the Department of Cardiaovascular Surgery, Guangdong Provincial People's Hospital from May 2020 to December 2021, were retrospectively analyzed. There were 14 males and 14 females, aging (51.1±14.0) years (range: 18 to 72 years). Enhanced cardiac computed tomography images were imported into Mimics software for preoperative three-dimensional reconstruction. The direction of the short axial plane of each segment was marked perpendicularly to the interventricular septum on the long axial plane of the digital cardiac model, then the thickness was measured on each short axial plane. A figurative digital model was used to determine the extent of resection and to visualize mitral valve and papillary muscle abnormalities. Correlation between the length, width, thickness, and volume of the predicted resected myocardium and those of the surgically resected myocardium was assessed by Pearson correlation analysis or Spearman correlation analysis. The accuracy of detecting mitral valve and papillary muscle abnormalities of transthoracic echocardiography and three-dimensional reconstruction was also compared. Results: There was no death or serious complications like permanent pacemaker implantation, re-sternotomy for bleeding, low cardiac output syndrome, stroke, or multiple organ dysfunction syndromes in the whole group. Namely, the obstruction of the left ventricular outflow tract was effectively relieved. The systolic anterior motion of the anterior mitral valve leaflet was absent in all patients after myectomy. The length, width, and thickness of the predicted resected myocardium by three-dimensional reconstruction were significantly positively correlated with the length (R=0.65, 95%CI: 0.37 to 0.82, P<0.01), width (R=0.39, 95%CI: 0.02 to 0.67, P<0.01), and thickness (R=0.82, 95%CI: 0.65 to 0.92, P<0.01) of the surgically resected myocardium, while the relation of the volume of the predicted resected myocardium and the volume of the surgically resected myocardium was a strong positive correlation (R=0.88, 95%CI: 0.76 to 0.94, P<0.01). Importantly, the interventricular septal myocardial thickness measured by preoperative transthoracic echocardiography showed a moderate positive correlation with the volume of surgically resected myocardium (R=0.52, 95%CI: 0.19 to 0.75, P<0.01). During a follow-up of (14.4±6.8) months (range: 3 to 22 months), no death occurred, and 1 patient was readmitted for endocardial radiofrequency ablation due to atrial fibrillation. Conclusion: Personalized three-dimensional reconstruction and printing can not only visualize the intracardiac structure but also guide septal myectomy by predicting the thickness, volume, and extent of resected myocardium to achieve ideal resection.

Left ventricular anatomy in obstructive hypertrophic cardiomyopathy: beyond basal septal hypertrophy.

Obstructive hypertrophic cardiomyopathy (oHCM) is characterized by dynamic obstruction of the left ventricular (LV) outflow tract (LVOT). Although this may be mediated by interplay between the hypertrophied septal wall, systolic anterior motion of the mitral valve, and papillary muscle abnormalities, the mechanistic role of LV shape is still not fully understood. This study sought to identify the LV end-diastolic morphology underpinning oHCM. Cardiovascular magnetic resonance images from 2398 HCM individuals were obtained as part of the NHLBI HCM Registry. Three-dimensional LV models were constructed and used, together with a principal component analysis, to build a statistical shape model capturing shape variations. A set of linear discriminant axes were built to define and quantify (Z-scores) the characteristic LV morphology associated with LVOT obstruction (LVOTO) under different physiological conditions and the relationship between LV phenotype and genotype. The LV remodelling pattern in oHCM consisted not only of basal septal hypertrophy but a combination with LV lengthening, apical dilatation, and LVOT inward remodelling. Salient differences were observed between obstructive cases at rest and stress. Genotype negative cases showed a tendency towards more obstructive phenotypes both at rest and stress. LV anatomy underpinning oHCM consists of basal septal hypertrophy, apical dilatation, LV lengthening, and LVOT inward remodelling. Differences between oHCM cases at rest and stress, as well as the relationship between LV phenotype and genotype, suggest different mechanisms for LVOTO. Proposed Z-scores render an opportunity of redefining management strategies based on the relationship between LV anatomy and LVOTO.

Implication Of Mitral Valve and Papillary Muscle Abnormalities Assessed Using Echocardiography in Hypertrophy Cardiomyopathy

Implication Of Mitral Valve and Papillary Muscle Abnormalities Assessed Using Echocardiography in Hypertrophy Cardiomyopathy

Mitral valve anomalies in transposition of the great arteries: Anatomical features, surgical management and outcomes

Mitral valve (MV) anomalies can be associated with transposition of the great arteries (TGA), but their influence on the choice of the surgical technique and the outcomes after anatomical repair, mainly mitral regurgitation (MR) and LVOT obstruction, have rarely been addressed. Our study objectives are to describe the MV anomalies found in patients with TGA, the different surgical procedures performed and the fate of the anomalous MV. From 1990 to 2020, 52 patients out of 1590 (3.3%) were identified. Main MV anomalies were a mitral cleft (88%) and anomalies of the subvalvular apparatus (60%) such as abnormal chordae attachments (16/52, 30.8%), straddling (6/52, 11.5%), accessory tissue (7/52, 13.5%) or an abnormal papillary muscle (4/52, 7.7%). The mitral cleft was described as anterior (ejection/outflow tract) in 40 and as AVSD-type in 6. A ventricular septal defect (VSD) was associated in 88.5% (58% outlet) ( Fig. 1 ). Main surgical procedure performed at repair was the arterial switch operation (ASO) ( n = 47, 90.4%). Two patients (3.8%) underwent a Bex-Nikaidoh procedure, 2 (3.8%) a half turned truncal rotation and 1 (1.9%) a “reparation à l’étage ventriculaire” (REV) procedure. Overall survival was 90% at 1 year and 88% at 10 and 20 years during a mean follow-up period of 9.5 years. Ten patients (19.2%) had a concomitant mitral procedure at repair (cleft closure in 7, procedure on the subvalvular apparatus in 6), of which 4 had a preoperative grade ≥ 2 MR. Five patients required reoperation for MR and/or for left ventricle outflow tract obstruction (LVOTO), none of them had previously undergone a mitral procedure at repair. All five underwent cleft closure, with LVOTO relief in 3. Freedom from MV reoperation was 96% at 1 year, 93% at 5 years, and 84.5% at 20 years. Main MV anomalies in TGA are the presence of an anterior cleft and abnormalities of the subvalvular apparatus, frequently associated with an outlet VSD. Mortality and reoperation rates are higher than in the other subtypes of TGA. Mitral repair at initial surgery should be considered only in cases of MR or LVOTO. Reoperation involves cleft closure and LVOTO relief. No MV replacement was required.

Comprehensive left ventricular outflow tract management beyond septal reduction to relieve obstruction.

The surgical management of patients with hypertrophic obstructive cardiomyopathy can be extremely challenging. Relieving the left ventricular outflow tract obstruction in these patients is often achieved by performing a septal myectomy. However, in many instances, septal reduction alone is not enough to relieve the obstruction. Interventions on the sub-valvular apparatus, including the anomalous chordae tendineae and the abnormal papillary muscles, are often required. In this review, we summarize the embryology and the pathophysiology of the different elements that may contribute to the left ventricular outflow tract obstruction in the setting of hypertrophic obstructive cardiomyopathy. In addition, we highlight the different surgical procedures that a surgeon may adopt to relieve the left ventricular outflow tract obstruction, beyond the septal myectomy.

Videoscope-assisted transaortic myectomy in patients with hypertrophic cardiomyopathy with complex left ventricular anatomy.

The transaortic approach is the most common method of septal myectomy. However, difficulties arise due to a limited view of the surgical field. Here, we report our experience with videoscope-assisted transaortic myectomy. We reviewed myectomy operations that were performed between July 2015 and June 2019 at Chung-Ang University Hospital, Seoul, South Korea. Patients who previously had cardiac surgery, alcohol septal ablation, or concomitant disease which required combined surgery, were excluded. Among the 21 patients included, 10 patients underwent videoscope-assisted transaortic myectomy (VA group), and 11 patients underwent myectomy in a conventional manner (CO group). The preoperative data, echocardiographic images, operative records, and postoperative outcomes of these patients were reviewed. There were no differences in baseline characteristics between groups VA and CO. The main indications for videoscope-assisted transaortic myectomy in group VA were midventricular septal muscle resection (70%), abnormal papillary muscle resection (40%), and abnormal chordal connection resection (30%). Eight (80%) patients had multiple indications for videoscope-assisted transaortic myectomy. There was no surgical mortality in either group. Postoperative patients showed less than moderate mitral regurgitation and a New York Heart Association class either III or IV. There were no differences in hospital days (9.5 vs. 12.0 days; p = .383), nor postoperative pressure gradient (14 vs. 15 mmHg; p > .99). Videoscope-assisted transaortic myectomy is an effective surgical technique in selective hypertrophic cardiomyopathy patients with complex intraventricular anatomy, diffuse hypertrophy, and midventricular obstruction.

The Use of 3D Echocardiography in Surgical Planning of the Mitral Valve in Pediatric Cardiology.

Mitral valve disease in pediatric cardiology is complex and can involve a combination of annular, leaflet, chordae tendineae and papillary muscle abnormalities. Transthoracic two-dimensional echocardiography (2DE) remains the primary diagnostic imaging technique utilized in pediatric surgical planning. However, given that the mitral valve is a three-dimensional (3D) structure, the addition of 3D echocardiography (3DE) to better define the mechanisms of stenosis and/or regurgitation is advantageous. Transthoracic 3DE technology has improved with advances in probe technology and ultrasound scanners, producing images with good spatial resolution and adequate temporal resolution. Specifically, the addition of pediatric 3D transducers with higher frequencies and a smaller footprint provides better 3DE imaging in children. Improved efficiency of 3DE acquisition and analysis allow 3D assessment of the mitral valve to be more easily integrated by the sonographer, the cardiologist and the surgeon in mitral valve assessment. This improvement was also made possible by the postprocessing software optimization. In this method paper, we aim to describe the transthoracic 3DE assessment of the mitral valve in children and its use in the surgical planning of pediatric mitral valve disease. Firstly, the 3DE assessment begins by selecting the correct probe and by obtaining a view of the mitral valve. Then, the appropriate data acquisition method should be selected based on the individual patient. Next, optimization of the data set is critical in order to properly balance spatial and temporal resolution. During live scanning or following acquisition, the data set can be cropped using innovative tools that allow the user to quickly obtain an infinite number of cut planes or volumetric reconstructions. The cardiologist and surgeon can view the mitral valve en face; thus, accurately reconstructing its morphology in order to support medical or surgical planning. Finally, a review of some clinical applications is proposed, showing examples in pediatric mitral valve managements.

Relationship between papillary muscles abnormalities and apparently unexplained infero-lateral T-wave inversion in athletes

Abstract Aims To evaluate by cardiac magnetic resonance (CMR) if left ventricle papillary muscle abnormalities, such as hypertrophy and abnormal location, may be the anatomo-functional substrates responsible for TWI inversion in lateral or infero-lateral leads in otherwise healthy athletes. Methods We included competitive athletes with TWI in lateral or infero-lateral leads in the absence of cardiac diseases detected by CMR. The control population included healthy athletes with normal ECG, matched for age and gender. We compared thickness, volume (both absolute and relative to the cardiac mass) and position of the papillary muscles between cases and controls. Results We included 53 athletes with apparently unexplained TWI in the lateral or infero-lateral leads (median age 20 years (17–42), 86.8% males) and 53 athletes with no TWI matched for age and gender. 4 patients (7.6%) had family history for cardiomyopathy or sudden cardiac death. Athletes with TWI showed more hypertrophic papillary muscles compared to controls, with statistically significant difference in diameter, area and volume (p&amp;lt;0.01). The median ratio between the papillary muscles and the left ventricular mass was 4.4% among athletes with TWI versus 3% among those without TWI (p&amp;lt;0.001). Papillary muscles showed apical displacement in 47% of cases, compared to 17% in the control group (p=0.001). Conclusions Idiopathic TWI in lateral or infero-lateral leads is associated with left ventricle papillary muscle hypertrophy and their apical displacement detected by CMR. The comprehension of clinical and prognostic significance of papillary muscle abnormalities responsible for these ventricular repolarization alterations requires further studies. Example Funding Acknowledgement Type of funding source: None

Multimodality Imaging for Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy, an inherited autosomal dominant disease, is the most common familial cardiovascular disorder and presents with heterogeneous pathobiological, clinical, and phenotypic features. This review will explore how multimodality cardiovascular imaging offers insight into understanding and identifying these heterogeneous features which are important to reliably diagnose and risk stratify patients with HCM. Beyond the left ventricular (LV) hypertrophy, multimodality imaging is able to fully characterize a number of structural and functional abnormalities seen in HCM such as mitral valve leaflet elongation, abnormal chordal attachment, accessory apical-basal muscle bundle, papillary muscle abnormalities, LV outflow tract (LVOT) obstruction, microvascular dysfunction, and fibrosis. These anatomical and functional abnormalities contribute to the spectrum of different HCM presentations. Recent research shows that various morphological subtypes of HCM present with distinct clinical, genetic, LVOT, and fibrosis characteristics. Late gadolinium enhancement as assessed by cardiac magnetic resonance imaging (CMR) is useful in risk stratification of patients with HCM. In addition, native T1 and extracellular volume may add to prognostication. Strain, as measured by echocardiography and CMR, and novel techniques, such as positron emission tomography, have shown promise in determining prognosis in HCM. Computed tomography evaluates not only for obstructive coronary artery disease, but also for variations in coronary anatomy. Complimentary use of these imaging modalities is crucial in comprehensive evaluation of HCM as well as in diagnosing various features of HCM, differentiating it from other cardiomyopathies, and in identifying prognosis.

Abnormal Papillary Muscle Signal on Cine MRI As a Typical Feature of Mitral Valve Prolapse

Background: Mitral valve prolapse (MVP) is characterized by an abnormal movement of the valvular apparatus which may affect the papillary muscles (PMs) function and structure. Aim of the study was to investigate abnormal PM signal in MVP by using cardiac magnetic resonance imaging (MRI). Methods and Results: We enrolled 47 consecutive patients with MVP evaluated by cardiac MRI. Additional groups included healthy volunteers, patients with moderate-to-severe mitral regurgitation (not caused by MVP) and patients with hypertrophic cardiomyopathy. Visual assessment of the PM signals was carried out and the signal intensity (SI) of both the antero-lateral and postero-medial PMs was normalized by that of the left ventricular (LV) parietal myocardium. Our results show that in the MVP group only, the PM signal intensity was significantly lower compared to the one of the LV parietal myocardium. This sign did not correlate with either LV late gadolinium enhancement or positive anamnesis for significant arrhythmias. Conclusions: In MVP patients only, PM signal is significantly reduced compared to LV parietal myocardium (“darker appearance”). The described findings are not clearly related to evidence of myocardial fibrosis, as assessed by MRI, and to previous occurrence of complex ventricular arrhythmias.

RARE COMPLICATION LEADING TO PEA ARREST IN HOCM

Mitral and papillary muscle abnormalities are common in HOCM but chordal rupture is a rare entity. 65-year-old male with past medical history of HOCM, sleep apnea, hypertension, obesity presented with syncope and was found to have non sustained ventricular tachycardia on evaluation. Echocardiogram

POSSIBLE MECHANISM OF LATE SYSTOLIC MITRAL VALVE PROLAPSE: SYSTOLIC SUPERIOR SHIFT OF LEAFLETS SECONDARY TO ANNULAR DILATATION THAT TRACTS PAPILLARY MUSCLE

In patients with late systolic mitral valve prolapse (MVP), progressive superior shift of mitral valve (MV) during systole is associated with abnormal papillary muscles (PMs) superior shift in late systolic MVP. Causal relation on these superior shifts remains unclarified. We hypothesized that the

Double- Chambered Left Ventricle and Abnormal Papillary Muscle Formation

Double- Chambered Left Ventricle and Abnormal Papillary Muscle Formation

Possible mechanism of late systolic mitral valve prolapse: systolic superior shift of leaflets secondary to annular dilatation that causes papillary muscle traction.

Progressive superior shift of the mitral valve (MV) during systole is associated with abnormal papillary muscle (PM) superior shift in late systolic MV prolapse (MVP). The causal relation of these superior shifts remains unclarified. We hypothesized that the MV superior shift is related to augmented MV superiorly pushing force by systolic left ventricular pressure due to MV annular dilatation, which can be corrected by surgical MV plasty, leading to postoperative disappearance of these superior shifts. In 35 controls, 28 patients with holosystolic MVP, and 28 patients with late systolic MVP, the MV coaptation depth from the MV annulus was measured at early and late systole by two-dimensional echocardiography. The PM tip superior shift was monitored by echocardiographic speckle tracking. MV superiorly pushing force was obtained as MV annular area × (systolic blood pressure - 10). Measurements were repeated after MV plasty in 14 patients with late systolic MVP. Compared with controls and patients with holosystolic MVP, MV and PM superior shifts and MV superiorly pushing force were greater in patients with late systolic MVP [1.3 (0.5) vs. 0.9 (0.6) vs. 3.9 (1.0) mm/m2, 1.3 (0.5) vs. 1.2 (1.0) vs. 3.3 (1.3) mm/m2, and 487 (90) vs. 606 (167) vs. 742 (177) mmHg·cm2·m-2, respectively, means (SD), P < 0.001]. MV superior shift was correlated with PM superior shift ( P < 0.001), which was further related to augmented MV superiorly pushing force ( P < 0.001). MV and PM superior shift disappeared after surgical MV plasty for late systolic MVP. These data suggest that MV annulus dilatation augmenting MV superiorly pushing force may promote secondary superior shift of the MV (equal to late systolic MVP) that causes subvalvular PM traction in patients with late systolic MVP. NEW & NOTEWORTHY Late systolic mitral valve prolapse (MVP) is associated with mitral valve (MV) and papillary muscle (PM) abnormal superior shifts during systole, but the causal relation remains unclarified. MV and PM superior shifts were correlated with augmented MV superiorly pushing force by annular dilatation and disappeared after surgical MV plasty with annulus size and MV superiorly pushing force reduction. This suggests that MV annulus dilatation may promote secondary superior shifts of the MV (late systolic MVP) that cause subvalvular PM traction.

Double- Chambered Left Ventricle and Abnormal Papillary Muscle Formation

Papillary muscles develop separately from mitral valve leaflet and chordae, they origin from myocardial ridge of the anterior wall and to the posterior wall of the left ventricle (LV). While chordae and mitral valve leaflets origin from a cushion tissue. The myocardial ridge gradually loosens from the ventricular wall and meanwhile the cushion tissue transforms into leaflet and chordae1. Abnormal papillary muscle formation may present a muscle bridge and divide the LV into two chambers. The most rare form is the superior inferior LV subdivision which our cases represent.