Papillary Muscle Insertion Research Articles

Stretch of the papillary insertion triggers reentrant arrhythmia: an in silico patient study.

The electrophysiological mechanism connecting mitral valve prolapse (MVP), premature ventricular complexes and life-threatening ventricular arrhythmia is unknown. A common hypothesis is that stretch activated channels (SACs) play a significant role. SACs can trigger depolarizations or shorten repolarization times in response to myocardial stretch. Through these mechanisms, pathological traction of the papillary muscle (PM), as has been observed in patients with MVP, may induce irregular electrical activity and result in reentrant arrhythmia. Based on a patient with MVP and mitral annulus disjunction, we modeled the effect of excessive PM traction in a detailed medical image-derived ventricular model by activating SACs in the PM insertion region. By systematically varying the onset of SAC activation following sinus pacing, we identified vulnerability windows for reentry with 1 ms resolution. We explored how reentry was affected by the SAC reversal potential and the size of the region with simulated stretch (SAC region). Finally, the effect of global or focal fibrosis, modeled as reduction in tissue conductivity or mesh splitting (fibrotic microstructure), was investigated. In models with healthy tissue or fibrosis modeled solely as CV slowing, we observed two vulnerable periods of reentry: For of -10 and -30 mV, SAC activated during the T-wave could cause depolarization of the SAC region which lead to reentry. For of -40 and -70 mV, SAC activated during the QRS complex could result in early repolarization of the SAC region and subsequent reentry. In models with fibrotic microstructure in the SAC region, we observed micro-reentries and a larger variability in which times of SAC activation triggered reentry. In these models, 86% of reentries were triggered during the QRS complex or T-wave. We only observed reentry for sufficiently large SAC regions ( 8 mm radius in models with healthy tissue). Stretch of the PM insertion region following sinus activation may initiate ventricular reentry in patients with MVP, with or without fibrosis. Depending on the SAC reversal potential and timing of stretch, reentry may be triggered by ectopy due to SAC-induced depolarizations or by early repolarization within the SAC region.

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.

C34 AN UNUSUAL CASE OF CARDIAC ARREST DUE TO TRAUMA–INDUCED QT PROLONGATION

Abstract Background QT prolongation is a well–known cause of sudden cardiac death due to polymorphic ventricular tachycardia triggered by early afterdepolarizations. Acquired long QT is a common finding in several clinical scenarios and invariably represents a high risk feature. Case Report An 84 years–old woman presented to our emergency department (ED) after experiencing a blunt chest trauma due to a car accident. She reported mild dyspnea and chest pain exacerbated by breathing and movement while denied palpitations and loss of consciousness. Baseline ECG showed atrial fibrillation with normal ventricular rate and a prolonged QT interval (QTc 640, Fig 1A) not present at previous ECGs. She did not assume any QT–prolonging drug and laboratory tests at admittance revealed troponin I values slightly elevated (29,6 ng/ml; n.v.: <11,6 ng/l) and no other significant abnormalities. A CT scan demonstrated a displaced fracture of the sternal body. Due to the QT prolongation, the patient was admitted for ECG monitoring.. During the stay in our ED the patient suffered a cardiac arrest. A torsade des pointes triggered by a late–coupled premature ventricular complex (PVC) was documented (Fig 1B). The arrhythmia was interrupted with external DC shock and magnesium solfate infusion was started. The coronary angiography demonstrated normal coronary arteries. The patient underwent cardiac magnetic resonance (CMR) four days later which showed transmural necrosis of the middle third of the lateral wall of the left ventricle at the insertion of the anterolateral papillary muscle (Fig 2). No further ventricular arrhythmias were observed and the patient was discharged after QTc normalization. Cardiac arrhythmias are a rare complication of cardiac contusion ranging from isolated PVCs to atrial or ventricular fibrillation. However, the role of the ECG in this peculiar subset is unclear. The most common ECG abnormalities are non specific ST–T wave changes, whereas in our case the marked QTc prolongation resulted in a closer monitoring of the patient allowing a prompt recognition of cardiac arrest. On the other hand CMR proved to be an effective method to identify a cardiac injury showing the typical pattern of myocardial damage associated with cardiac contusion (stress–induced lesions at the insertions of papillary muscles due to sudden increase of left ventricular pressure) and, thus, could be adopted as a useful tool to identify patients at higher risk for arrhythmic complications.

Deep learning automates detection of wall motion abnormalities via measurement of longitudinal strain from ECG-gated CT images.

4D cardiac CT (cineCT) is increasingly used to evaluate cardiac dynamics. While echocardiography and CMR have demonstrated the utility of longitudinal strain (LS) measures, measuring LS from cineCT currently requires reformatting the 4D dataset into long-axis imaging planes and delineating the endocardial boundary across time. In this work, we demonstrate the ability of a recently published deep learning framework to automatically and accurately measure LS for detection of wall motion abnormalities (WMA). One hundred clinical cineCT studies were evaluated by three experienced cardiac CT readers to identify whether each AHA segment had a WMA. Fifty cases were used for method development and an independent group of 50 were used for testing. A previously developed convolutional neural network was used to automatically segment the LV bloodpool and to define the 2, 3, and 4 CH long-axis imaging planes. LS was measured as the perimeter of the bloodpool for each long-axis plane. Two smoothing approaches were developed to avoid artifacts due to papillary muscle insertion and texture of the endocardial surface. The impact of the smoothing was evaluated by comparison of LS estimates to LV ejection fraction and the fractional area change of the corresponding view. The automated, DL approach successfully analyzed 48/50 patients in the training cohort and 47/50 in the testing cohort. The optimal LS cutoff for identification of WMA was -21.8, -15.4, and -16.6% for the 2-, 3-, and 4-CH views in the training cohort. This led to correct labeling of 85, 85, and 83% of 2-, 3-, and 4-CH views, respectively, in the testing cohort. Per-study accuracy was 83% (84% sensitivity and 82% specificity). Smoothing significantly improved agreement between LS and fractional area change (R 2: 2 CH = 0.38 vs. 0.89 vs. 0.92). Automated LV blood pool segmentation and long-axis plane delineation via deep learning enables automatic LS assessment. LS values accurately identify regional wall motion abnormalities and may be used to complement standard visual assessments.

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.

Left ventricular remodelling in mitral valve prolapse patients: implications of apical papillary muscle insertion.

Mitral valve prolapse (MVP) causes left ventricular (LV) remodelling even in the absence of significant mitral regurgitation. To evaluate whether apical insertion of the papillary muscle (PM) influences the pattern and severity of MVP-related LV remodelling. All MVP patients who underwent CMR at our institution between December 2008 and December 2019 were included, thoroughly reviewed and grouped according to apical/non-apical PM insertion. Apical PM insertion was found in 53/92 patients (58%) and associated with mitral leaflet thickening (P < 0.01) and a trend towards higher prevalence of mitral annular disjunction (P = 0.05). Whereas no differences in ventricular volumes or ejection fraction were found, patients with apical PM insertion showed more lateral wall remodelling with mid lateral wall thinning [2.1 (1.8-2.5) vs. 4.0 (3.5-5.0) mm, P < 0.01], increased LV eccentricity and a lower GCS at this level (15 ± 3% vs. 20 ± 3%, P < 0.01). In long-axis direction, increased end-diastolic mid lateral wall angulation was found (i.e. angle <155° measured in the thinnest point of the mid lateral wall in four-chamber view) with a higher angle variation during systole (25 ± 11° vs. 17 ± 8°, P < 0.01). Remarkably, PM fibrosis was significantly more frequent in patients with apical PM insertion (i.e. 66% vs. 28%, P < 0.01). Finally, a higher burden of premature ventricular complexes (>5%) and non-sustained ventricular tachyarrhythmias was found in patients with apical PM insertion: 53% vs. 25% (P = 0.04) and 38% vs. 18% (P = 0.04), respectively. Apical PM insertion is part of the phenotypic spectrum of MVP, impacts significantly LV remodelling, and potentially may be related to increased ventricular arrhythmogenicity.

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.

Isolated Non-Compaction of Right Ventricular Myocardium, A Rare Congenital Anomaly and Role of Echocardiogram: A Case Report

The ventricular non-compaction or spongy myocardium is a rare congenital cardiomyopathy which is caused by defective morphogenesis of myocardium during embryonic life. It is characterised by excessive, coarse trabeculations within ventricular myocardium beyond papillary muscle insertion which communicates freely with the ventricular cavity. This carries high risk for development of serious arrhythmia, thromboembolic stroke, pump failure etc. Isolated LV involvement is the most common presentation (68%) and biventricular involvement is the next most common presentation (22-38%). Isolated non-compaction of RV myocardium is a rare anomaly. We are hereby presenting such a case.

Left ventricular wall thickness measured with computed tomography predicts clinical outcomes in patients receiving cardiac resynchronization therapy

BackgroundUp to 30% of selected heart failure patients do not benefit clinically from cardiac resynchronization therapy (CRT). Left ventricular (LV) wall thickness (WT) analyzed using computed tomography (CT) has rarely been evaluated in response to CRT and mitral regurgitation (MR) improvement. PurposeWe examined the association of LVWT and the ability for reverse LV remodeling and MR improvement after CRT. MethodsFifty-four patients scheduled for CRT underwent pre-procedural CT. Reduced LVWT was defined as WT<6mm and quantified as a percentage of total LV area. End points were 6-month clinical and echocardiographic response to CRT (NYHA class, LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV) and LV end-systolic volume (LVEDV)), MR improvement and 2-year major adverse cardiac events (MACE). ResultsPatients were divided in 3 groups according to the percentage of LVWT<6mm area: ≤20%; 20–50% and ≥50%. At 6 months, 75%, 71% and 42% of the patients experienced NYHA improvement in the ≤20%, 20–50% and ≥50% group respectively. Additionally, ≤20% group presented higher LVEF, LVEDV and LVESV positive response rate (86%, 59% and 83% respectively). Both 20–50% and ≥50% groups exhibited a lower LVEF, LVEDV and LVESV positive response rate (52% and 42%; 47% and 45%; 53% and 45%, respectively). Additionally, ≥25% of LVWT<6mm inclusive of at least 1 papillary muscle insertion was the only predictor of lack of MR improvement. Lastly, ≥50% group experienced significantly lower 2-years MACE survival free probability. ConclusionWT evaluated using CT could help to stratify the response to CRT and predict MR improvement and outcomes.

Left ventricular wall thickness assessed by cardiac computed tomography and cardiac resynchronization therapy outcomes.

Up to 30% of selected heart failure patients do not benefit clinically from cardiac resynchronization therapy (CRT). Left ventricular (LV) wall thickness (WT) analysed using computed tomography (CT) has rarely been evaluated in response to CRT and mitral regurgitation (MR) improvement. We examined the association of LVWT and the ability to reverse LV remodelling and MR improvement after CRT. Fifty-four patients scheduled for CRT underwent pre-procedural CT. Reduced LVWT was defined as WT <6 mm and quantified as a percentage of total LV area. Endpoints were 6-month clinical and echocardiographic response to CRT [New York Heart Association (NYHA) class, LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV), and LV end-systolic volume (LVESV)], MR improvement and 2-year major adverse cardiac events (MACE). Patients were divided into three groups according to the percentage of LVWT <6 mm area: ≤20%, 20-50%, and ≥50%. At 6 months, 75%, 71%, and 42% of the patients experienced NYHA improvement in the ≤20%, 20-50%, and ≥50% group, respectively. Additionally, ≤20% group presented higher LVEF, LVEDV, and LVESV positive response rate (86%, 59%, and 83%, respectively). Both 20-50% and ≥50% groups exhibited a lower LVEF, LVEDV, and LVESV positive response rate (52% and 42%; 47% and 45%; and 53% and 45%, respectively). Additionally, ≥25% of LVWT <6 mm inclusive of at least one papillary muscle insertion was the only predictor of lack of MR improvement. Lastly, ≥50% group experienced significantly lower 2-year MACE survival free probability. WT evaluated using CT could help to stratify the response to CRT and predict MR improvement and outcomes. NCT01097733.

P3804Left ventricular wall thickness measured with computed tomography predicts mitral regurgitation improvement in patients implanted with cardiac resynchronization therapy

Abstract Background Secondary mitral regurgitation (MR) is common in heart failure (HF) patients and results in progressive left ventricular (LV) dilatation, papillary muscle (PM) displacement and mitral valve leaflet tethering. In selected HF patients, cardiac resynchronization therapy (CRT) has been proved to reduce MR by LV reverse remodeling, resynchronization of PM insertion site contraction and reduction in MV tenting area and inter PM distance. However, data regarding the impact of LV wall thickness (WT) on MR improvement are scarce. Methods In this prospective study, a total 54 patients scheduled for CRT, underwent pre procedural CT. Reduced LV WT was defined as WT&lt;6mm and was quantified as a percentage of total LV area. LV was segmented in 17 segments to assess the number of LV segments with reduced WT. End point was 6-month echocardiographic MR improvement by ≥1 class. For this analysis, we focused on patient with mild (class 2) to severe (class 4) MR. Results Among the 54 patients, 38 (70.4%) had mild to severe MR at baseline and a total of 16 (42.1%) experienced MR improvement by ≥1 class at 6 months. there was no difference regarding the co-morbidities, electrocardiogram and echocardiographic parameters between patients with or without MR improvement. However, patients without MR improvement had significant higher NT-pro BNP level at baseline. Interestingly, patients without MR improvement had larger LVWT &lt;6mm area (41.541.5±19.4 vs. 22.4±16.1%, p=0.003) associated with higher number of papillary muscle (PM) inserted in reduced LV WT area. In multivariate analysis, an area ≥25% of LVWT&lt;6mm including at least 1 PM insertion was the only predictor of no MR improvement at 6 months (HR 18.4 (1.25–271.75), p=0.034). Lastly, patients with MR improvement had significant lower rate of basal segments with reduced WT, especially in the lateral location. Of note, patients with MR improvement exhibited fewer rate of postero-lateral WT &lt;6mm segments. Left ventriculat segmentation Conclusion LV WT evaluated using CT is a strong predictor of no MR improvement in HF patients with mild to severe MR and who scheduled for CRT implantation.

Structural abnormalities in hypertrophic cardiomyopathy beyond left ventricular hypertrophy by multimodality imaging evaluation.

Echocardiography- and cardiovascular magnetic resonance (CMR)-based studies have revealed a wide range of phenotypic manifestations in hypertrophic cardiomyopathy (HCM) apart from hypertrophy. This study sought to comprehensively describe a number of structural abnormalities in HCM beyond hypertrophy, by multimodality imaging. A total of 100 HCM patients were prospectively enrolled, undergoing standard and contrast echocardiography, and CMR. Morphological characteristics involving mitral valve leaflets (MVL), subvalvular apparatus, and left ventricular cavity and wall were investigated. Seventy healthy volunteers served as control population. As assessed by echo, MVLs were longer in HCM patients than in controls (anterior method 1: 24[22,28] vs 19[18,20] mm, P<0.01; anterior method 2: 27[24, 29] vs 21[19, 23] mm, P<0.01; posterior: 15[12,19] vs 14[13,15] mm, P<0.01). Abnormal chordal attachment to anterior MVL, anterior papillary muscle displacement, and accessory apical-basal muscle bundle were present in 42 (42%), 61 (61%), and 35 (35%) patients, respectively (P values vs controls <0.01); direct papillary muscle insertion into MVL and hypertrabeculation were found in two and five patients, respectively. Contrast echocardiography (n=94) detected myocardial crypts in 15 patients (16%). Overall, 83% of HCM subjects had at least one of these phenotypic manifestations. Echocardiography and CMR agreement for MVL length was poor, while for structural characteristics was moderate to substantial (Cohen's Kappa: 0.53-1.00). Except for posterior MVL length and hypertrabeculation, the phenotypic characteristics studied had acceptable reproducibility by echocardiography and CMR. Structural abnormalities in HCM beyond hypertrophy are significantly common. Multimodality imaging approach to these HCM facets by echocardiography and CMR is feasible and desirable.

Direct insertion of papillary muscle into mitral valve leaflets in a healthy patient without hypertrophic cardiomyopathy

We present the case of a healthy young woman that was evaluated before participation in amateur sports. A systolic and diastolic murmur was heard during the physical examination. Two-dimensional echocardiography was performed, and a direct insertion of the posteromedial papillary muscle into the mitral valve leaflets was found. Mild mitral stenosis and moderate regurgitation were also found. Because she was asymptomatic, a follow-up in 6months was planned to control the evaluation of her valve disease.

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.

Mechanistic Features Associated With Improvement in Mitral Regurgitation After Cardiac Resynchronization Therapy and Their Relation to Long-Term Patient Outcome

Background— Mechanisms of mitral regurgitation (MR) reduction with cardiac resynchronization therapy (CRT) are complex, and their association with long-term outcome is unclear. We sought to elucidate mechanistic features of reduction in MR with CRT, which impact long-term patient survival. Methods and Results— A prospective longitudinal study of 277 patients with heart failure with QRS width ≥120 ms and ejection fraction ≤35% for CRT was performed. Quantitative echocardiography, including dyssynchrony analysis, was performed at baseline. MR was quantified by color Doppler before and 6 months after CRT. Predefined end points of death, transplant, or left ventricular assist device were tracked during 4 years. There were 114 (48%) patients with CRT with significant MR (≥moderate) at baseline; of whom 48 (42%) patients had MR improvement, and 24 (19%) patients had MR worsening after CRT. The 66 events (47 deaths, 10 transplantations, and 9 left ventricular assist devices) were strongly associated with significant MR after CRT (hazard ratio, 3.58; 95% confidence interval, 2.18–5.87; P &lt;0.0001). Three echocardiographic features were independently associated with amelioration of significant MR after CRT by multivariable analysis: anteroseptal to posterior wall radial strain dyssynchrony &gt;200 ms, lack of severe left ventricular dilatation (end-systolic dimension index &lt;29 mm/m 2 ), and lack of echocardiographic scar at papillary muscle insertion sites (all P &lt;0.05) and, when combined, were additively associated with long-term survival ( P =0.0001). Conclusions— Significant MR after CRT was strongly associated with less favorable long-term survival. Echocardiographic mechanistic features were identified that were associated with improvement in MR after CRT and favorable long-term survival.

Papillary Muscle Insertion Directly into the Anterior Mitral Leaflet in Hypertrophic Cardiomyopathy, Its Identification and Cause of Outflow Obstruction by Cardiac Magnetic Resonance Imaging, and Its Surgical Management

This case presents an uncommon but important mechanism of muscular left ventricular outflow obstruction in hypertrophic cardiomyopathy due to anomalous and direct papillary muscle insertion into the anterior mitral leaflet, a finding reliably identified clinically by cardiac magnetic resonance imaging. The identification of this left ventricular outflow tract morphology is important before invasive ventricular septal reduction therapy because it dictates a specific surgical strategy. These findings further support the role of cardiac magnetic resonance imaging in the early evaluation of hypertrophic cardiomyopathy patients.

Apically displaced papillary muscles mimicking apical hypertrophic cardiomyopathy

Apical hypertrophic cardiomyopathy (ApHCM) is a subtype of hypertrophic cardiomyopathy, which is clinically suspected by a characteristic giant negative T (GNT) wave on electrocardiogram (ECG) and diagnosed by demonstrating apical hypertrophy on ECG. However, GNT may not always be specific for ApHCM as in this report of apically displaced papillary muscle (ADPM). By retrospectively collecting 12-lead ECGs with a GNT wave and apical hypertrophy on 2D-ECG from 2008 to 2010, we identified 55 patients with both of these findings. ADPM was defined to be present when the base of the papillary muscle originated from the apical one-third of the left ventricle. A diagnosis of ApHCM in patients with apical hypertrophy but without evidence of ADPM was given otherwise. Careful evaluations of 2D-ECGs suggested that 20% (11/55) of all patients had an ADPM mimicking ApHCM. Baseline clinical and echocardiography data were not different between the two except for the maximal T wave on 12-lead ECG and apicoseptal hypertrophy, suggesting that the differentiation of these two groups may be subtle and difficult. In addition, patients with ADPM frequently showed abnormal insertion of papillary muscle into the left ventricular outflow tract or into the base of mitral valve leaflet. These findings suggest that ADPM may also be present with GNT on 12-lead ECG and emphasizes the careful evaluation of the left ventricular apex for proper diagnosis and discrimination of ApHCM.