An accessory mitral valve leaflet causing left ventricular outflow tract obstruction and associated with severe aortic incompetence

This case report describes a 20-year-old woman with Turner's syndrome who presented with reduced effort tolerance limited by dyspnea. She had previously been on pediatric cardiology follow-up for congenital subvalvular aortic stenosis first diagnosed at age 7. Unfortunately she defaulted after two visits before any intervention could be done. Transthoracic echocardiography demonstrated severe aortic incompetence (AI) with a membrane-like structure in the left ventricular outflow tract (LVOT). The mean pressure gradient across the LVOT on continuous wave Doppler was 41 mmHg. The membranous interventricular septum appeared aneurysmal and it was observed that the "subaortic membrane" had a connection to the anterolateral papillary muscle via a strand of chordal tissue. Further images were captured using two-dimensional and three-dimensional transthoracic and transesophageal echocardiography (iE33, Philips Medical Systems, Andover, MA, USA). After a review of the literature it was concluded that this appeared to be an accessory mitral valve (AMV) leaflet causing LVOT obstruction associated with AI. AMV tissue is a rare congenital malformation causing LVOT obstruction. Because it is so unusual, it may not be immediately recognizable even in a high volume echocardiography laboratory. The clue which helped with the diagnosis was the strand of chordal tissue which connected the mass to the papillary muscle. This anomaly is often associated with LVOT obstruction.     

Critical left ventricular outflow tract obstruction due to accessory mitral valve tissue

Left ventricular outflow tract (LVOT) obstruction due to anomalous tissue tag arising from the mitral valve is a rare congenital cardiac anomaly. It generally becomes symptomatic during the first decade of life as exercise intolerance, chest pain, or syncope at effort. To date, only a few cases of critical systemic obstruction due to isolated mitral valve anomaly in neonates have been reported. We report the case of a neonate who was a few hours old and was referred in severe clinical condition due to critical left ventricular outflow obstruction resulting from an anomalous tissue tag of mitral valve origin.     

Mechanisms,pathophysiology, and diagnostic imaging of left ventricular outflow tract obstruction following mitral valve surgery and transcatheter mitral valve replacement

Left ventricular outflow tract obstruction is a serious complication of mitral valve surgery (repair and replacement) and transcatheter mitral valve replacement. An appreciation of the various mechanisms which cause outflow obstruction in these settings is critical to avoiding this complication and to initiating appropriate treatment. This article discusses the mechanisms, pathophysiology, and imaging of left ventricular outflow tract obstruction which can arise following insertion of a variety of mitral valve prosthetics.     

An unusual cause of left ventricular outflow tract obstruction

Left ventricular outflow tract obstruction (LVOTO) has been reported with bio-prosthetic and mechanical mitral valves (MV), though it is more common with the former. The obstruction can be dynamic or fixed. We hereby report a case of fixed LVOTO following bio-prosthetic MV replacement (MVR).     

Transient left ventricular outflow tract obstruction with systolic anterior motion of the mitral valve: A stunning cause

Left ventricular outflow tract obstruction (LVOTO) and systolic anterior motion (SAM) of the mitral valve may have various etiologies, of which hypertrophic cardiomyopathy is the most common. More rarely, an acute coronary syndrome, myocardial stunning, and takotsubo cardiomyopathy may give rise to LVOTO and SAM. Here, we present a 70‐year‐old female patient with a non‐ST‐elevation acute coronary syndrome treated with percutaneous coronary intervention. Echocardiography the day after, because of dyspnea and hypotension, revealed apical akinesia, LVOTO, and SAM, which proved completely reversible after treatment with a β‐blocker and a 2‐month follow‐up period. It was concluded that postischemic apical stunning had caused LVOTO and SAM.     

Midterm outcomes of right ventricular outflow tract reconstruction using the Freestyle xenograft

Objective: Various options exist for right ventricular outflow tract (RVOT) recon‐struction in congenital heart disease. The Freestyle porcine aortic root may be usedbut its longevity is not well defined.
Design: We performed a retrospective review of all non‐Ross RVOT reconstructionsusing the Freestyle root in our institution. Survival and reintervention, either by sur‐gery, transcatheter valve implantation, balloon valvuloplasty, or bare metal stent placement, were recorded. Factors associated with reintervention were assessedusing Cox regression.
Results: Between January 2002 and December 2015, there were 182 patients identi‐fied. Sixteen patients were lost to follow‐up and 3 patients died, unrelated to cardiacsurgery. Of the remaining 163 patients, the median age was 12.2 years (interquartilerange 6.4‐16.4), median weight was 39.0 kg (interquartile range 19.9‐59.3), and themedian body surface area was 1.23 m² (interquartile range 0.79‐1.64). Ninety‐three(57%) patients had tetralogy of Fallot. The median follow‐up was 5.4 years (inter‐quartile range 2.9‐8 years). There were no operative or cardiac‐related deaths. Thirty‐eight patients (23%) required reintervention. The rate of freedom from rein‐tervention was 93.2% (95% CI 86.7%‐96.6%) at 5 years and 48.4% (95% CI34.9%‐60.6%) at 10 years. Age < 10 years, weight < 39 kg, and body surface area<1.2 m2 at the time of valve placement, as well as valve size ≤25 mm were signifi‐cantly associated with need for earlier reintervention.
Conclusions: The Freestyle root in the RVOT is associated with excellent survival andlow midterm need for reintervention. Its longevity is comparable to published data on homografts and other bioprosthetic valves.     

Left ventricular outflow tract obstruction from mitral prosthesis

A case of left ventricular outflow tract obstruction six years following mitral valve replacement is presented. Clinical features, echocardiographic and angiographic studies preoperatively all suggested aortic valve disease. The diagnosis of left ventricular outflow tract obstruction by the strut of the mitral prosthesis was made intraoperatively. Enlargement of the aortic root and aortic valve replacement resulted in good symptomatic and echocardiographic improvement.     

A rare combination of Ebstein's anomaly with left ventricular outflow tract obstruction

We describe a rare case of Ebstein's anomaly (EA) combined with left ventricular outflow tract obstruction in a 54-year-old man that was accurately identified by echocardiography, cardiac magnetic resonance imaging (CMR). The imaging result was ultimately validated by surgery. We emphasize the clinical importance of using echocardiography and CMR together to provide a thorough, noninvasive explanation of these results.     

Special considerations in mapping and ablation of focal ventricular arrhythmias originating from the left ventricular outflow tract in patients with a transcatheter aortic valve replacement

Transcatheter aortic valve replacements (TAVRs) have been increasingly performed in high‐risk patients with severe aortic stenosis. Focal ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT) can occur after a TAVR, and radiofrequency catheter ablation (RFCA) should be considered as a treatment option when those VAs are drug‐refractory. There are specific challenges in the RFCA of LVOT VAs after a TAVR because the tubular structure of the TAVR device sits in the LVOT. However, if the anatomical background of the TAVR and LVOT VAs are well understood and the anatomical relationship between the TAVR device and LVOT is sufficiently evaluated, RFCA of LVOT VAs in patients with a TAVR should be safe and highly successful.     

Left ventricular outflow tract obstruction after mitral valve repair treated with alcohol septal ablation

Left ventricular outflow tract (LVOT) obstruction due to systolic anterior motion of the mitral valve (SAM) occurs in 4–5% of patients after mitral valve repair. If conservative treatment is unsuccessful, reoperation is indicated. Treatment options include repeated mitral valve repair or valve replacement and septal myectomy if hypertrophy is present. We report a case of a patient with pre‐operatively undiagnosed hypertrophic cardiomyopathy who suffered from progressive dyspnea post‐operation due to severe LVOT obstruction with SAM. This case was successfully treated with catheter‐based alcohol septal ablation. © 2013 Wiley Periodicals, Inc.     

Left ventricular outflow tract obstruction as a cause for hypotension and symptoms during dobutamine stress echocardiography

Background: Hypotension has been found to occur in more than one-third of patients during DBSE. Unlike traditional treadmill exercise stress testing, hypotension does not appear to be associated with significant coronary artery disease or left ventricular (LV) dysfunction. Several ischemic and nonis-chemic mechanisms such as dynamic LV intracavitary obstruction have been implicated in the pathogenesis of hypotension and the induction of symptoms during DBSE. Hypothesis: The purpose of this study was the prospective evaluation of patients referred for dobutamine stress echocardiography (DBSE) to determine (1) the frequency of hypotension during DBSE, (2) the underlying mechanisms responsible for the induction of hypotension, and (3) to describe the cardiac chamber sizes and mass of patients in whom hypotension occurs. Methods: Seventy-eight consecutive patients were studied during DBSE. Pulsed and continuous-wave Doppler echocardiography were performed at baseline and at each dobutamine infusion stage. Maximum velocities were recorded. Cardiac output was determined noninvasively at each stage in patients who developed an outflow tract gradient. Echocardiography was used to characterize LV dimensions and mass. Results: During dobutamine infusion, 14 of 78 (18%) patients developed a left ventricular outflow tract (LVOT) velocity ≥ 2.5 m/s. Pulsed Doppler echocardiography verified that the maximal velocity originated in the LVOT. Of the patients who developed an LVOT gradient, 57% had a concomitant hypotensive response to dobutamine compared with 33% of patients without a gradient (not significant). Four of nine patients had a simultaneous fall in cardiac output. Patients who developed an LVOT gradient had smaller LV dimensions and increased wall thicknesses compared with those who did not develop a gradient. Conclusions: Dobutamine stress echocardiography precipitates LVOT obstruction in certain patients. The development of a gradient corresponded with a fall in blood pressure and a decline in cardiac output in nearly half of the patients. These findings suggest that stress-induced LVOT obstruction may be responsible in part for the hemodynamic changes and symptoms experienced by these patients during exercise.     

Fixed left ventricular outflow tract obstruction mimicking hypertrophic obstructive cardiomyopathy: pitfalls in diagnosis

We present a case series that highlights the diagnostic challenges with left ventricular hypertrophy (LVH) and left ventricular outflow tract obstruction (LVOTO). Fixed structural lesions causing LVOTO with secondary LVH may mimic hypertrophic obstructive cardiomyopathy (HOCM). Management of these two entities is critically different. Misdiagnosis and failure to recognize fixed left ventricular outflow tract (LVOT) lesions may result in morbidity as a result of inappropriate therapy and delay of definitive surgical treatment. It is thus necessary to identify the correct type and level of obstruction in the LVOT by careful correlation of clinical examination, Doppler evaluation, and advanced imaging findings.     

左心室中部肥厚合并二尖瓣冗长致左室流出道梗阻——病例报告与文献复习

目的:探讨左室流出道梗阻的病因分类、临床表现和诊治进展。方法:对1例左心室中部肥厚合并二尖瓣前叶冗长致隐匿性左室流出道梗阻患者的诊治过程进行全程追踪随访,结合复习相关文献。结果:左室流出道梗阻病因复杂,发生率较高;超声心动图运动试验结合经食道超声探查是左室流出道梗阻最有效的无创筛查和随访评价手段,必要时左心室造影和测压可进一步明确诊断。结论:对左心室肥厚患者常规开展运动超声心动图、必要时左心室造影等多种影像学检查可以有效提高左室流出道梗阻及其病因的诊断正确率。     

Reduction of left ventricular outflow tract obstruction with transcatheter mitral valve repair

Many patients with severe mitral regurgitation cannot undergo conventional mitral valve surgery due to prohibitive surgical risk and are candidates for transcatheter repair with an edge‐to‐edge technique. Prior reports suggest efficacy with this approach for mitral regurgitation due to hypertrophic cardiomyopathy with left ventricular outflow obstruction. We present a case report of transcatheter mitral valve repair for posterior leaflet prolapse with concomitant left ventricular outflow tract obstruction due to systolic anterior motion of the mitral valve in the absence of hypertrophic cardiomyopathy.     

特发性左心室流出道心外膜侧室性心动过速

目的报道9例经电生理检查证实的特发性左心室流出道心外膜侧室性心动过速(室速)的体表心电图及电生理检查特点.方法男性5例,女性4例,年龄15～58岁,6例为运动诱发的持续性室速,3例为运动诱发的非持续性室速.结果室速时,9例体表心电图QRS波全部呈现右束支阻滞图形(8例胸前导联V1-V6呈现高R波),Ⅱ、Ⅲ、aVF导联为高R波,Ⅰ、aVL导联为QS波.电生理检查,右心室和左心室心内膜标测未发现最早心室激动点,在较早心室心内膜激动处的心内电图多呈现起始部低幅电位,提示远场电位.心室内起搏标测未发现与室速体表心电图12导联QRS波形态相同的起搏点.8例通过心脏静脉系统标测发现最早的心室激动点[体表心电图最早QRS波前15～50ms,平均(32±12)ms]和完全或近乎完全的起搏标测位于心大静脉的远端1例、心前间隔静脉的近端7例.1例患者在左心室流出道消融成功,1例患者在心大静脉远端血管内消融成功.其他患者在右心室和/或左心室内消融失败.结论心脏静脉标测可以鉴别出特发性左心室流出道心外膜侧室速.