Resection of hypertrophic papillary muscles and mitral valve replacement in a patient with midventricular hypertrophic obstructive cardiomyopathy - a new approach

Midventricular hypertrophic obstructive cardiomyopathy (HOCM) is characterized by hypertrophy of the interventricular septum (IVS) and - in rare cases - of the papillary muscles (PM), which subsequently can cause dynamic left ventricular outflow tract obstruction (LVOTO) and severe heart failure symptoms. We report on a rare case of a 44-year-old patient suffering from midventricular HOCM with hypertrophic anterolateral PM and an additional chorda between the PM and the IVS.We describe a new surgical approach via right anterolateral thoracotomy in 3-dimensional (3D) video-assisted minimal-invasive technique with resection of hypertrophic PMs as well as the entire mitral valve-apparatus and valve replacement avoiding septal myectomy and potentially associated complications. After an uneventful procedure clinical symptoms improved from NYHA III-IV at baseline to NYHA 0-I postoperatively and remained stable over a follow-up period of 24 months. Therefore, the presented technique may be considered as a new and alternative approach in patients with hypertrophic PMs and hypertrophic IVS as subtype of midventricular HOCM.

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

OBJECTIVES

The 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.

METHODS

A 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.

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 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).

CONCLUSIONS

In 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.

Anatomical and biometric study of the mitral valve apparatus: application in valve repair surgery

OBJECTIVE

Most mitral valve repair techniques provide excellent surgical results by removing regurgitation, but all of these techniques simultaneously reduce posterior valve mobility. A comprehensive biometric study of the mitral valve apparatus will provide landmarks that would help improve this posterior valve mobility.

MATERIALS AND METHODS

Thirty one (31) human hearts have been studied, from 14 women and 17 men. The characteristics of the studied sample were analyzed descriptively. The difference in means of the variables between women and men were tested using a Student t test. Correlations between the different measures were determined by simple regression analysis. Mean values are shown with ± 1 standard deviation and the limit of significance was set at 0.05.

RESULTS

The mean weight of the hearts was 275.3 ± 2.4 g. The anteroposterior diameter of the mitral annulus was 29.3 ± 1.22 mm, the intertrigonal distance was 25.2 ± 3.50 mm and the anterior leaflet to posterior leaflet ratio was 1.9 ± 0.10, the length of the chordae A2 = 19.4 ± 1.15 mm and P2 = 14.5 ± 0.85 mm. The length of the anterior papillary muscle averaged 30.9 ± 7.20 mm and that of the posterior one 30.0 ± 8.75 mm. The comparison of the different values measured between women and men showed no statistically significant difference (p > 0.05). There was no correlation between these different measured values (p > 0.05).

CONCLUSION

A perfect knowledge of anatomy and biometry is therefore essential to offer alternative techniques that reproduce the real anatomy and physiology with a complete reconstruction of the mitral valve.

Irregular ventricular tachycardia originating from the moderator band

Ventricular tachycardias (VT) may initially show beat to beat oscillations but rapidly stabilize into a regular tachycardia with a stable cycle length. A persistently irregular ventricular tachycardia is a rare phenomenon. We report a rare case of an "irregular" ventricular tachycardia with so pronounced oscillations in cycle length that it was initially misdiagnosed as atrial fibrillation with aberrant conduction. This ventricular tachycardia was incessant and resulted in a tachycardia induced cardiomyopathy refractory to several antiarrhythmic drugs. Mapping of the right ventricle demonstrated that the tachycardia had a focal origin in the moderator band close to its insertion into the anterior papillary muscle. Radiofrequency ablation eliminated the tachycardia with eventual normalization of left ventricular function. The moderator band and anterior papillary muscle of the right ventricle are known to be the source of short-coupled ventricular premature beats and regular ventricular tachycardias. However, an "irregular" ventricular tachycardia has not been previously reported to arise from these structures.

The high-intensity interval training mitigates the cardiac remodeling in spontaneously hypertensive rats

AIM

To evaluate the influence of high-intensity interval training (HIIT) on cardiac structural and functional characteristics and myocardial mitogen-activated protein kinase (MAPK) signaling in hypertensive rats.

METHODS

Male rats (12 months old) were divided into three groups: Wistar Kyoto rats (WKY, n = 8); sedentary spontaneously hypertensive rats (SED-SHR, n = 10), and trained spontaneously hypertensive rats (HIIT-SHR, n = 10). Systolic blood pressure (SBP), functional capacity, echocardiography, isolated papillary muscle, and gene expression of MAPK gene-encoding proteins associated with Elk1, cJun, ATF2, MEF2 were analyzed.

KEY FINDINGS

HIIT decreased SBP and increased functional capacity, left ventricular diastolic diameter, posterior wall thickness-left ventricle, relative wall thickness-left ventricle, and resting tension of the papillary muscle. In hypertensive rats, we observed a decrease in the gene-encoding ATF2 protein; this decrease was reversed by HIIT.

SIGNIFICANCE

The influence of HIIT in the SHR model in the compensated hypertension phase generated an increase in cardiac hypertrophy, attenuated myocardial diastolic dysfunction, lowered blood pressure, improved functional capacity, and reversed the alteration in gene-encoding ATF2 protein.

Idiopathic posterior papillary muscle rupture; a case report

BACKGROUND

Papillary muscle rupture is a rare condition. Its clinical presentation, diagnosis and management can be very challenging for the clinician.

CASE PRESENTATION

A 73-year-old woman with hypertension presented with chest pain, ST-segment changes, and elevated serum troponin levels. Coronary angiography was normal. Echocardiography revealed normal ventricular function, flail posterior mitral leaflet, and severe mitral regurgitation. She underwent emergent mitral valve replacement.

CONCLUSION

The diagnostic and management strategies of this uncommon presentation are discussed.

In Vitro Mitral Valve Model with Unrestricted Ventricular Access: Using Vacuum to Close the Valve and Enable Static Trans-Mitral Pressure

Current in vitro models of the left heart establish the pressure difference required to close the mitral valve by sealing and pressurizing the ventricular side of the valve, limiting important access to the subvalvular apparatus. This paper describes and evaluates a system that establishes physiological pressure differences across the valve using vacuum on the atrial side. The subvalvular apparatus is open to atmospheric pressure and accessible by tools and sensors, establishing a novel technique for experimentation on atrioventricular valves. Porcine mitral valves were excised and closed by vacuum within the atrial chamber. Images were used to document and analyze closure of the leaflets. Papillary muscle force and regurgitant flow rate were measured to be 4.07 N at 120 mmHg and approximately 12.1 ml/s respectively, both of which are within clinically relevant ranges. The relative ease of these measurements demonstrates the usefulness of improved ventricular access at peak pressure/force closure.

Catheter ablation of frequent monomorphic ventricular arrhythmias in Andersen-Tawil syndrome: case report and focused literature review

BACKGROUND/PURPOSE

Andersen-Tawil syndrome type 1 is a rare autosomal dominant disease caused by a KCNJ2 gene mutation and clinically characterized by dysmorphic features, periodic muscular paralysis, and frequent ventricular arrhythmias (VAs). Although polymorphic and bidirectional ventricular tachycardias are prevalent, PVCs are the most frequent VAs. In addition, a "dominant" morphology with RBBB pattern associated with either superior or inferior axis is seen in most of the patients. Due to the limited efficacy of most antiarrhythmic drugs, catheter ablation (CA) is an alternative in patients with monomorphic VAs. Based on our experience, we aimed to review the arrhythmogenic mechanisms and substrates for VAs, and we analyzed the potential reasons for CA failure in this group of patients.

METHODS

Case report and focused literature review.

RESULTS

Catheter ablation has been reported to be unsuccessful in all of the few cases published so far. Most of the information suggests that VAs are mainly originated from the left ventricle and probably in the Purkinje network. Although identifying well-established and accepted mapping criteria for successful ablation of a monomorphic ventricular arrhythmia, papillary muscles seem not to be the right target.

CONCLUSIONS

More research is needed to understand better the precise mechanism and site of origin of VAs in Andersen-Tawil syndrome patients with this particular "dominant" monomorphic ventricular pattern to establish the potential role of CA.

Prognostic value of cardiovascular magnetic resonance left ventricular volumetry and geometry in patients receiving an implantable cardioverter defibrillator

BACKGROUND

Current indications for implantable cardioverter defibrillator (ICD) implantation for sudden cardiac death prevention rely primarily on left ventricular (LV) ejection fraction (LVEF). Currently, two different contouring methods by cardiovascular magnetic resonance (CMR) are used for LVEF calculation. We evaluated the comparative prognostic value of these two methods in the ICD population, and if measures of LV geometry added predictive value.

METHODS

In this retrospective, 2-center observational cohort study, patients underwent CMR prior to ICD implantation for primary or secondary prevention from January 2005 to December 2018. Two readers, blinded to all clinical and outcome data assessed CMR studies by: (a) including the LV trabeculae and papillary muscles (TPM) (trabeculated endocardial contours), and (b) excluding LV TPM (rounded endocardial contours) from the total LV mass for calculation of LVEF, LV volumes and mass. LV sphericity and sphere-volume indices were also calculated. The primary outcome was a composite of appropriate ICD shocks or death.

RESULTS

Of the 372 consecutive eligible patients, 129 patients (34.7%) had appropriate ICD shock, and 65 (17.5%) died over a median duration follow-up of 61 months (IQR 38-103). LVEF was higher when including TPM versus excluding TPM (36% vs. 31%, p < 0.001). The rate of appropriate ICD shock or all-cause death was higher among patients with lower LVEF both including and excluding TPM (p for trend = 0.019 and 0.004, respectively). In multivariable models adjusting for age, primary prevention, ischemic heart disease and late gadolinium enhancement, both LVEF (HR per 10% including TPM 0.814 [95%CI 0.688-0.962] p = 0.016, vs. HR per 10% excluding TPM 0.780 [95%CI 0.639-0.951] p = 0.014) and LV mass index (HR per 10 g/m2 including TPM 1.099 [95%CI 1.027-1.175] p = 0.006; HR per 10 g/m2 excluding TPM 1.126 [95%CI 1.032-1.228] p = 0.008) had independent prognostic value. Higher LV end-systolic volumes and LV sphericity were significantly associated with increased mortality but showed no added prognostic value.

CONCLUSION

Both CMR post-processing methods showed similar prognostic value and can be used for LVEF assessment. LVEF and indexed LV mass are independent predictors for appropriate ICD shocks and all-cause mortality in the ICD population.

Predictors of moderate to severe ischemic mitral regurgitation after myocardial infarction: a cardiac magnetic resonance study

OBJECTIVES

The purpose of this study is to explore the predictors of moderate to severe ischemic mitral regurgitation (IMR) after myocardial infarction with cardiovascular magnetic resonance (CMR).

METHODS

From January 2016 to September 2018, 109 patients (mean age 60 ± 8 years) with IMR were studied retrospectively. All patients underwent CMR-cine with True-FISP sequence and late gadolinium enhancement (LGE) with a phase-sensitive inversion recovery sequence. The presence of papillary muscle infarction (PMI), global left ventricular (LV) infarcted extent, LV functional parameters, and LV myocardial strain were assessed. Univariate and multivariate analyses were performed to identify factors in the development of moderate to severe IMR.

RESULTS

Mild IMR was present in 61 patients (56%), and moderate to severe IMR was present in 48 patients (44%). PMI was identified in 22 patients (20.1%); 14 of them (63.63%) showed a moderate or severe IMR. Global LV infarcted extent was increased in patients with moderate to severe IMR (p < 0.001). LV functional parameters of patients with moderate to severe IMR were statistically different from those of the patients with mild IMR (all p < 0.001), except the LV SV index (p = 0.142) and LV CI (p = 0.447). The global longitudinal strain (GLS), regional radial strain (RS), and circumferential strain (CS) of the moderate-to-severe IMR group were significantly decreased compared with those of the mild IMR group (p < 0.05). In multivariable analyses, age (OR = 1.11; p = 0.001), global LV infarct extent (OR = 1.14; p = 0.000), and GLS (OR = 1.31; p = 0.000) were associated with moderate-to-severe chronic IMR.

CONCLUSIONS

The incidence of PMI was higher in patients with moderate-to-severe IMR. The extent of global LV infarcted extent and GLS were independent predictors of moderate-to-severe IMR.

KEY POINTS

• Cardiovascular magnetic resonance late gadolinium enhancement and feature-tracking imaging provide reliable information on LV function, myocardial viability, and papillary muscle morphology. • Papillary muscle infarction is not an independent predictor of moderate-to-severe IMR. • The extent of global LV infarction and LV global longitudinal strain were independent predictors of moderate-to-severe chronic IMR.

Preparation of Neonatal Rat Papillary Muscles for Contractile Studies

Isolated cardiac tissue allows investigators to study mechanisms underlying normal and pathological conditions, which would otherwise be difficult or impossible to perform in vivo. In contrast to ventricular muscle strip preparations, papillary muscles can be prepared without severely damaging the muscle tissue. In this preparation, the isolated papillary muscle is fixed in an environmentally controlled organ bath chamber and electrically stimulated. The evoked twitch force is recorded using a pressure transducer, and parameters such as twitch force amplitude and twitch kinetics are analyzed. A variety of experimental protocols can be performed to investigate the calcium- and frequency-dependent contractility as well as dose-response curves of contractile agents, as well as simulation of pathologic conditions such as acute cardiac ischemia. Mouse papillary muscle preparations have long been the mainstay for studying interactions between intracellular calcium regulation and contractile responses under a number of simulated pathophysiological conditions. These studies are often used to complement in vitro studies performed using isolated neonatal rat cardiac myocytes. In this procedure, we describe how neonatal rat papillary muscles can also be prepared for use in contractile studies.

Multipolar mapping for catheter ablation of premature ventricular complexes originating from papillary muscles in the structurally normal heart: a case series

Background

Previous studies on radiofrequency catheter ablation of premature ventricular complexes (PVCs) arising from the left ventricle (LV) papillary muscles (PM) show a modest procedural success rate with higher recurrence rate. Our study sought to explore the utility of using a multipolar mapping with a steerable linear duodecapolar catheter for ablating the PM PVCs.

Methods

Detailed endocardial multipolar mapping was performed using a steerable linear duodecapolar catheter in 6 consecutive PM PVCs patients with structurally normal heart. The clinical features and procedural data as well as success rate were analysed.

Results

LV endocardial electroanatomic mapping was performed in all patients via a retrograde aortic approach using a duodecapolar mapping catheter. All patients displayed a PVC burden with 16.2 ± 5.4%. Duodecapolar catheter mapping demonstrated highly efficiency with an average procedure time (95.8 ± 7.4 min) and fluoroscopy time (14.2 ± 1.5 min). The mean number of ablation applications points was 6.8 ± 1.9 with an average overall ablation duration of 6.1 ± 3.0 min. The values of earliest activation time during mapping using duodecapolar catheter were 37.8 ± 7.2 ms. All patients demonstrated acute successful ablation, and the PVC burden in all patients after an average follow-up of 8.5 ± 2.0 months was only 0.7%. There were no complications during the procedures and after follow-up.

Conclusions

Mapping and ablation of PM PVCs using a duodecapolar catheter facilitated the identification of earliest activation potentials and pace mapping, and demonstrated a high success rate during follow-up.

Mechanical and morphometric study of mitral valve chordae tendineae and related papillary muscle

The mitral valve (MV) apparatus is a complex mechanical structure including annulus, valve leaflets, papillary muscles (PMs) and connected chordae tendineae. Chordae anchor to the papillary muscles to help the valve open and close properly during one cardiac cycle. It is of paramount importance to understand the functional, mechanical, and microstructural properties of mitral valve chordae and connecting PMs. In particular, little is known about the biomechanical properties of the anterior and posterior papillary muscle and corresponding chords. In this work, we performed uniaxial and biaxial tensile tests on the anterolateral (APM) and posteromedial papillary muscle (PPM), and their respective corresponding chordae tendineae, chordae^APM and chordae^PPM, in porcine hearts. Histology was carried out to link the microstructure and macro-mechanical behavior of the chordae and PMs. Our results demonstrate that chordae^PPM are less in number, but significantly longer and stiffer than chordae^APM. These different biomechanical properties may be partially explained by the higher collagen core ratio and larger collagen fibril density of chordae^PPM_. No significant mechanical or microstructural differences were observed along the circumferential and longitudinal directions of APM and PPM samples. Data measured on chordae and PMs were further fitted with the Ogden and reduced Holzapfel - Ogden strain energy functions, respectively. This study presents the first comparative anatomical, mechanical, and structural dataset of porcine mitral valve chordae and related PMs. Results indicate that a PM based classification of chordae will need to be considered in the analysis of the MV function or planning a surgical treatment, which will also help developing more precise computational models of MV.

Changes in rat myocardium contractility under subchronic intoxication with lead and cadmium salts administered alone or in combination

Subchronic intoxications induced in male rats by repeated intraperitoneal injections of lead acetate and cadmium chloride, administered either alone or in combination, are shown to affect the biochemical, cytological and morphometric parameters of blood, liver, heart and kidneys. The single twitch parameters of myocardial trabecular and papillary muscle preparations were measured in the isometric regime to identify changes in the heterometric (length-force) and chronoinotropic (frequency-force) contractility regulation systems. Differences in the responses of these systems in trabecules and papillary muscles to the above intoxications are shown. A number of myocardium mechanical characteristics changing in rats under the effect of a combined lead-cadmium intoxication and increased proportion of α-myosin heavy chains were observed to normalize fully or partially if such intoxication was induced against background administration of a proposed bioprotective complex. Based on the experimental results and literature data, some assumptions are suggested concerning the mechanisms of the cardiotoxic effects produced by lead and cadmium.

Magnetic resonance imaging of the papillary muscles of the left ventricle: normal anatomy, variants, and abnormalities

Left ventricular papillary muscles are small myocardial structures that play an important role in the functioning of mitral valve and left ventricle. Typically, there are two groups of papillary muscles, namely the anterolateral and the posteromedial groups. Cardiovascular magnetic resonance (CMR) is a valuable imaging modality in the evaluation of papillary muscles, providing both morphological and functional information. There is a remarkably wide variation in the morphology of papillary muscles. These variations can be asymptomatic or associated with symptoms related to LV outflow tract obstruction, often associated with hypertrophic cardiomyopathy. Abnormalities of the papillary muscles range from congenital disorders to neoplasms. Parachute mitral valve is the most common congenital abnormality of papillary muscles, in which all the chordae insert into a single papillary muscle. Papillary muscles can become dysfunctional, most commonly due to ischemia. Papillary muscle rupture is a major complication of acute myocardial infarction that results in mitral regurgitation and associated with high mortality rates. The most common papillary neoplasm is metastasis, but primary benign and malignant neoplasms can also be seen. In this article, we discuss the role of CMR in the evaluation of papillary muscle anatomy, function, and abnormalities.

Reactive oxygen species impair the excitation-contraction coupling of papillary muscles after acute exposure to a high copper concentration

Copper is an essential metal for homeostasis and the functioning of living organisms. We investigated the effects of a high copper concentration on the myocardial mechanics, investigating the reactive oxygen species (ROS) mediated effects. The developed force of papillary muscles was reduced after acute exposure to a high copper concentration and was prevented by co-incubation with tempol, DMSO and catalase. The reuptake of calcium by the sarcoplasmic reticulum was reduced by copper and restored by tempol. The contractile response to Ca²⁺ was reduced and reversed by antioxidants. The response to the β-adrenergic agonist decreased after exposure to copper and was restored by tempol and catalase. In addition, the in situ detection showed increased O₂^·- and OH^·. Contractions dependent on the sarcolemmal Ca²⁺ influx were impaired by copper and restored by antioxidants. Myosin-ATPase activity decreased significantly after copper exposure. In conclusion, a high copper concentration can acutely impair myocardial excitation-contraction coupling, reduce the capacity to generate force, reduce the Ca²⁺ inflow and its reuptake, and reduce myosin-ATPase activity, and these effects are mediated by the local production of O₂^·-, OH^· and H₂O₂. These toxicity effects of copper overload suggest that copper is a risk factor for cardiovascular disease.

Papillary muscles of left ventricle-Morphological variations and it's clinical relevance

Introduction

The two left ventricular papillary muscles are small structures at sternocostal and inferior wall but are vital to mitral valve competence. Extra papillary muscles could be found. Partial or complete rupture, complicating acute myocardial infarction, causes severe or even catastrophic mitral regurgitation, potentially correctable by surgery. Detailed knowledge of normal anatomy and variations is vital for accurate interpretation of information by echocardiography and for surgical repair.

Materials and methods

The material for present study consisted of 52 formalin fixed adult apparently normal cadaveric hearts belonging to either sex obtained from the Department of Anatomy. These hearts were dissected carefully to open the left ventricle and to expose the papillary muscles. According to their attitudinal position they were described as supero-lateral (S-L) and inferoseptal muscle (I-S) instead of conventional anterolateral and posteromedial. Different morphological features of papillary muscles were noted and measurements were taken.

Results

Classical picture of left ventricular papillary muscle was found only in 25% cases. Additionally extra muscles were found 34.61% and 71.15% in S-L and I-S group, respectively. Different shapes and pattern of papillary muscles were also been identified. An additional attribute of this study was measurement of length and breadth of papillary muscles which thus provides a base line data for further detailed studies in a large scale.

Conclusion

Oriental nomenclature is necessary not only for anatomist but also for electrocardiographers. Breadth of papillay muscle should be taken into morphometric account as for screening of hypertrophic cardiomyopathy. Proper anatomical knowledge is crucial for clinicians, surgeons and radiologists.

[Preliminary clinical efficacy of percutaneous transcystic papilla balloon dilation for removing common bile duct stones]

Objective: To evaluate the feasibility, safety, and preliminary efficacy of percutaneous transcystic papilla balloon dilation for the common bile duct stones. Methods: A total of 11 patients with the common bile duct stones without dilatation of the intrahepatic bile ducts treated with percutaneous transcystic papilla balloon dilation in multiple center from April 2013 to May 2015 were analyzed retrospectively.In these 11 patients, there were 3 males and 8 females.And the average age was 68(52-91) years old.All patients had no obviously dilated intrahepatic bile duct, 6 patients were not suitable for endoscopic treatment or surgery, 4 patients refused endoscopic or surgical treatment and 1 patient had a history of failed endoscopic treatment.The white blood cell count, CA19-9, total bilirubin, direct bilirubin, AST, ALT and serum amylase level were recorded before the procedure, 1 week, and 1 month later.Early complications, such as cholangitis, pancreatitis, hemorrhage, and perforation were evaluated. Results: Technical success was achieved in all the 11 cases.The level of CA19-9, total bilirubin and direct bilirubin decreased significantly 1 week and 1 month after the procedure.One patient suffered from biliary tract infection.No severe complications, such as perforation of biliary or gastrointestinal tract, occurred during the follow up.Common bile duct stone recurred in 1 patient 2 years after the procedure. Conclusions: For cases who are not suitable for endoscopic treatment, surgery, or percutaneous transhepatic approach to treat the common bile duct stones, percutaneous transcystic papilla dilation is technically feasible and safe, and seems to be an appropriate alternative strategy.

Intracardiac echo-facilitated 3D electroanatomical mapping of ventricular arrhythmias from the papillary muscles: assessing the 'fourth dimension' during ablation

AIMS

Ventricular arrhythmias (VA) originating from a papillary muscle (PM) have recently been described as a distinct clinical entity with peculiar features that make its treatment with catheter ablation challenging. Here, we report our experience using an intracardiac echo-facilitated 3D electroanatomical mapping approach in a case series of patients undergoing ablation for PM VA.

METHODS AND RESULTS

Sixteen patients who underwent catheter ablation for ventricular tachycardia (VT) or symptomatic premature ventricular contractions originating from left ventricular PMs were included in the study. A total of 24 procedures (mean 1.5 per patient) were performed: 15 using a retrograde aortic approach and 9 using a transseptal approach. Integrated intracardiac ultrasound for 3D electroanatomical mapping was used in 15 of the 24 procedures. The posteromedial PM was the most frequent culprit for the clinical arrhythmia, and the body was the part of the PM most likely to be the successful site for ablation. The site of ablation was identified based on the best pace map matching the clinical arrhythmia and the site of earliest the activation. At a mean follow-up of 10.5 ± 7 months, only two patients had recurrent arrhythmias following a repeat ablation procedure.

CONCLUSION

An echo-facilitated 3D electroanatomical mapping allows for real-time creation of precise geometries of cardiac chambers and endocavitary structures. This is useful during procedures such as catheter ablation of VAs originating from PMs, which require detailed representation of anatomical landmarks. Routine adoption of this technique should be considered to improve outcomes of PM VA ablation.

Impact of the papillary muscles on cardiac magnetic resonance image analysis of important left ventricular parameters in hypertrophic cardiomyopathy

PURPOSE

The use of cardiac magnetic resonance (CMR) analysis has increased in patients with hypertrophic cardiomyopathy (HCM). Quantification of left ventricular (LV) measures will be affected by the inclusion or exclusion of the papillary muscles as part of the LV mass, but the magnitude of effect and potential consequences are unknown.

METHODS

We performed Cine-CMR in (1) clinical HCM patients (n = 55) and (2) subclinical HCM mutation carriers without hypertrophy (n = 14). Absolute and relative differences in LV ejection fraction (EF) and mass were assessed between algorithms with and without inclusion of the papillary muscles.

RESULTS

Papillary muscle mass in group 1 was 6.6 ± 2.5 g/m(2) and inclusion of the papillary muscles resulted in significant relative increases in LVEF of 4.5 ± 1.8 % and in LV mass of 8.7 ± 2.6 %. For group 2 these figures were 4.0 ± 0.9 g/m(2), 3.8 ± 1.0 % and 9.5 ± 1.8 %, respectively. With a coefficient of variation of 4 %, this 9 % difference in LV mass during CMR follow-up will be considered a change, while in fact the exact same mass may have been assessed according to two different algorithms.

CONCLUSIONS

In clinical HCM patients, CMR quantification of important LV measures is significantly affected by inclusion or exclusion of the papillary muscles. In relative terms, the difference was similar in subjects without hypertrophy. This underscores a general need for a uniform approach in CMR image analysis.

Movement of mitral fibrous components in an isolated porcine working heart model

BACKGROUND

There is little research regarding the movement of mitral fibrous components. We analyzed changes in mitral fibrous components in normal and deteriorated isolated working swine hearts.

METHODS

In 5 swine hearts, 6 sonomicrometry transducers were placed around the mitral annulus and 2 in the papillary muscle tip. During the working cycle, we evaluated the annular dimension and calculated the contraction range and contraction ratio during the cardiac cycle in normal and deteriorated modes.

RESULTS

The transverse (24.5 ± 2.3 vs. 27.4 ± 2.4 mm) and posterior longitudinal diameter (18.3 ± 7.0 vs. 22.5 ± 5.5 mm) increased significantly in deteriorated mode. The contraction range in transverse (1.8 ± 0.6 vs. 0.8 ± 0.7 mm) and posterior longitudinal (1.6 ± 0.6 vs. 0.8 ± 0.3 mm) diameters decreased significantly in deteriorated mode. The contraction range of the strut chordae was less than 1.0 mm in both modes, with no significant differences. The contraction ratio of the anterior strut chordae was significantly reduced in deteriorated mode (3.2 ± 1.1% vs. 2.2 ± 1.1%). The contraction ratio of the annulus was significantly lower in deteriorated mode with respect to transverse (6.9 ± 2.1% vs. 2.9 ± 2.9%) and longitudinal (13.3 ± 4.5% vs. 8.6 ± 5.1%) diameters.

CONCLUSIONS

In the deteriorated hearts, the mitral annulus was dilated and contractility decreased. The length of the strut chordae differed 1 mm between the deteriorated and normal modes; however, the contraction ratio of the anterior chordae during the cardiac cycle was reduced, indicating increased stretching.

Morphometry and aberrant morphology of the adult human tricuspid valve leaflets

The tricuspid valve complex has been studied since the beginning of the twentieth century, and variations in the structural orientation of the tricuspid leaflets has been reported before, as the occurrence of accessory leaflets poses a major problem during surgeries related to the tricuspid valve. In this study, 36 adult formalin-fixed human hearts were analyzed to compare the number, form and size of the tricuspid leaflets. The result shows that in right ventricles, the number of leaflets can vary from the routine three to as many as seven, and the localization of such accessory leaflets of the tricuspid valve differs between specimens. Five leaflet forms were the most common, and the 'typical' form of tricuspid valves with no accessory leaflets was only present in a small percentage of the cases studied. Measurements of the main and accessory leaflets showed that the anterior leaflets were the largest, followed by the inferior leaflets, while the septal and the accessory leaflets were the smallest in size. On the basis of these results, it is suggested that three leaflets of the tricuspid valve are relatively uncommon, with frequent occurrences of accessory leaflets. The multicuspidal form of the tricuspid valve therefore raises concern about understanding the functional and physiological significance of the accessory leaflets.

Effect of papillary muscles and trabeculae on left ventricular measurement using cardiovascular magnetic resonance imaging in patients with hypertrophic cardiomyopathy

Objective

To evaluate the influence of papillary muscles and trabeculae on left ventricular (LV) cardiovascular magnetic resonance (CMR) analysis using three methods of cavity delineation (classic or modified inclusion methods, and the exclusion method) in patients with hypertrophic cardiomyopathy (HCM).

Materials and Methods

This retrospective study included 20 consecutive HCM patients who underwent 1.5-T CMR imaging with short-axis cine stacks of the entire LV. LV measurements were performed using three different methods of manual cavity delineation of the endocardial and epicardial contours: method A, presumed endocardial boundary as seen on short-axis cine images; method B, including solely the cavity and closely adjacent trabeculae; or method C, excluding papillary muscles and trabeculae. Ascending aorta forward flow was measured as reference for LV-stroke volume (SV). Interobserver reproducibility was assessed using intraclass correlation coefficients.

Results

Method A showed larger end-diastole and end-systole volumes (largest percentage differences of 25% and 68%, respectively, p < 0.05), compared with method C. The ejection fraction was 55.7 ± 6.9% for method A, 68.6 ± 8.4% for B, and 71.7 ± 7.0% for C (p < 0.001). Mean mass was also significantly different: 164.6 ± 47.4 g for A, 176.5 ± 50.5 g for B, and 199.6 ± 53.2 g for C (p < 0.001). LV-SV error was largest with method B (p < 0.001). No difference in interobserver agreement was observed (p > 0.05).

Conclusion

In HCM patients, LV measurements are strikingly different dependent on whether papillary muscles and trabeculae are included or excluded. Therefore, a consistent method of LV cavity delineation may be crucial during longitudinal follow-up to avoid misinterpretation and erroneous clinical decision-making.

Successful repair of critical tricuspid regurgitation secondary to a ruptured papillary muscle in a neonate

Severe tricuspid regurgitation resulting from a flail leaflet is a rare cause of neonatal cyanosis. We report a neonate with profound cyanosis and severe tricuspid regurgitation caused by a rupture of the papillary muscle supporting the anterior leaflet, without other structural heart defects. Ductal patency could not be established. The repair of the tricuspid valve was performed after initial stabilization by using extracorporeal membrane oxygenation.

Strain balance of papillary muscles as a prerequisite for successful mitral valve repair in patients with mitral valve prolapse due to fibroelastic deficiency

AIMS

The aim of this study was to assess the papillary muscle strain as a contributor to recurrent mitral regurgitation (MR) after mitral valve repair for fibroelastic deficiency.

METHODS AND RESULTS

Sixty-four patients with isolated posterior mitral valve prolapse and severe MR referred for surgery were prospectively recruited between 2008 and 2012. Two- and three-dimensional echocardiography and speckle tracking were performed in all patients. The longitudinal strain of the anterolateral (AL) and posteromedial (PM) papillary muscles was individually calculated as well as the global longitudinal strain of both papillary muscles was measured before and after mitral repair and normalized to left ventricle end-diastolic volume. Eight patients (12.5%) had at least moderate MR 6 months after mitral repair. The longitudinal strain of the AL (preop -4.94 ± 2.2 vs. postop -3.28 ± 1.3, P < 0.001) and the PM papillary muscles (preop -12.64 ± 5.3 vs. postop -4.12 ± 6.77, P < 0.001) as well as the global strain of both papillary muscles (preop -7.59 ± 3.48 vs. postop -1.07 ± 6, P < 0.001) were all reduced after surgical repair. The longitudinal strain of the PM papillary muscle was the strongest predictor of recurrent MR (when less than or equal to -14.78). The global preoperative papillary muscle strain was also a determinant of recurrent MR when the global strain was greater than -9.05% (area under the curve: 0.895, sensitivity: 100%, and specificity: 76.8%).

CONCLUSIONS

Patients with isolated posterior mitral leaflet prolapse are less likely having any residual MR post repair when the global papillary muscle strain of both papillary muscles is close or equal to zero. Strain of the papillary muscles may be an important determinant in predicting residual MR in patients who undergo mitral valve repair.

Electrophysiological characteristics related to outcome after catheter ablation of idiopathic ventricular arrhythmia originating from the papillary muscle in the left ventricle

BACKGROUND AND OBJECTIVES

The electrophysiological properties associated with favorable outcome of radiofrequency catheter ablation (RFCA) for idiopathic ventricular arrhythmia (VA) originating from the papillary muscle (PM) remain unclear. The purpose of this study was to investigate the relationships of electrophysiological characteristics and predictors with the outcome of RFCA in patients with VAs originating from PM in the left ventricle (LV).

SUBJECTS AND METHODS

Twelve (4.2%) of 284 consecutive patients with idiopathic VAs originating from LV PM were assessed. The electrophysiological data were compared between the patients in the successful group and patients in the recurrence group after RFCA.

RESULTS

In 12 patients with PM VAs, non-sustained ventricular tachycardias (VTs, n=6), sustained VTs (n=4) and premature ventricular complexes (n=2) were identified as the presenting arrhythmias. Seven of eight patients showing high-amplitude discrete potentials at the ablation site had a successful outcome (85.7%), while the remaining four patients who showed low-amplitude fractionated potentials at the ablation site experienced VA recurrence. The mean duration from onset to peak downstroke (Δt) on the unipolar electrogram was significantly longer in the successful group than in the recurrence group (58±8 ms vs. 37±9 ms, p=0.04). A slow downstroke >50 ms of the initial Q wave on the unipolar electrogram at ablation sites was also significantly associated with successful outcome (85.7% vs. 25.0%, p=0.03).

CONCLUSION

In PM VAs, the high-amplitude discrete potentials before QRS and slow downstroke of the initial Q wave on the unipolar electrogram at ablation sites were related to favorable outcome after RFCA.

Severe Mitral Regurgitation due to Traumatic Anterolateral Papillary Muscle Rupture: A Case Report

A 29-year-old man was admitted for abrupt dyspnea and hemoptysis. An echocardiogram revealed severe mitral regurgitation due to papillary muscle rupture for which an emergency mitral valve replacement operation was performed 4 days after admission. Herein, we report our experience with this case along with a review of the literature.