Systolic anterior motion of the mitral valve after mitral valve repair: a method of prevention

Factors predisposing patients to systolic anterior motion of the mitral valve (SAM) with left ventricular outflow tract (LVOT) obstruction after mitral valve repair are the presence of a myxomatous mitral valve with redundant leaflets, a nondilated hyperdynamic left ventricle, and a short distance between the mitral valve coaptation point and the ventricular septum after repair. From December 1999 through March 2000, we used our surgical method in 6 patients with severely myxomatous regurgitant mitral valves who were at risk of developing SAM. Leaflets were markedly redundant in all 6. Left ventricular function was hyperdynamic in 4 patients and normal in 2. Triangular or quadrangular resection of the midportion of the posterior leaflet and posterior band annuloplasty were performed. To prevent SAM and LVOT obstruction, extra, posteriorly directed, mid-posterior-leaflet secondary chordae tendineae, which would otherwise have been resected, were transferred to the underside of the middle of the mid-anterior leaflet with a small piece of associated valve as an anchoring pledget. This kept the redundant anterior leaflet edge, which extended below the coaptation point, away from the LVOT No post-repair SAM or LVOT obstruction was observed on intraoperative or discharge echocardiography. All patients had no or trivial residual mitral regurgitation. We conclude that extra chordae tendineae, when available, can be used in mitral valve repair to tether the redundant anterior leaflet and thus prevent it from flipping into the LVOT. This will theoretically prevent SAM and LVOT obstruction in patients with risk factors for SAM.     

非肥厚型心肌病引起的二尖瓣前叶收缩期前向运动

二尖瓣前叶收缩期前向运动(SAM)是心脏收缩期间二尖瓣前叶向室间隔的运动,SAM可导致严重的二尖瓣反流和左心室流出道梗阻。SAM多见于肥厚型心肌病,同时还可发生于二尖瓣修复术后、急性心肌梗死、Takotsubo综合征、主动脉瓣置换术后等情况。理解SAM的发生条件和产生机制对早期识别和治疗至关重要。     

SAM-systolic anterior motion of the anterior mitral valve leaflet post-surgical mitral valve repair

Systolic anterior motion (SAM) is a postoperative complication experienced by patients undergoing mitral valve repair. The incidence of SAM after mitral valve repair ranges from 5 to 10%. Early recognition of the signs and symptoms of SAM is imperative to the management of these patients. This article presents the pathophysiology of mitral valve dysfunction to give the practitioner a clear understanding of the dynamics of SAM. This article's main focus is the detection and management of SAM and the most current treatment modalities. A case study is used to illustrate the complex management necessary for the patient with SAM.     

Systolic anterior motion of the mitral valve after Carpentier ring valvuloplasty for mitral valve prolapse

Between July 1983 and March 1985, 45 patients with severe mitral regurgitation underwent mitral valvuloplasty with insertion of a semirigid Carpentier ring. No patient had echocardiographic evidence of systolic anterior motion (SAM) preoperatively, whereas 5 patients had this echocardiographic finding postoperatively. All 5 had mitral valve prolapse as their underlying disease process and SAM developed at varying intervals after valvuloplasty. The development of SAM is related to insertion of the semirigid ring, persistence of a redundant anterior mitral leaflet, narrowing of the left ventricular (LV) outflow tract and the Venturi effect. LV and aortic pressure measurements with simultaneous Doppler echocardiography have confirmed the presence of a significant LV outflow tract gradient in these patients. Although all 5 patients are functionally improved after mitral valvuloplasty, the long-term implications of SAM after valvuloplasty are unknown.     

Delayed systolic anterior motion after mitral valve repair

A rare case of systolic anterior motion (SAM) after mitral valve repair is described. A temporary postoperative left ventricular (LV) dysfunction protected against this complication during the early postoperative period. Only on day 9 postoperatively did the left ventricle recover and SAM develop, with significant obstruction of the LV outflow tract. Subsequently, mitral valve replacement was required. This case demonstrates the importance of the LV geometrical relationships that predispose to this complication.     

Genesis of systolic anterior motion (SAM) of the mitral valve in patients with aortic regurgitation

This study was performed to evaluate the incidence and genesis of systolic anterior motion (SAM) of the mitral valve apparatus in patients with aortic regurgitation (AR). The study population consisted of 44 patients with non-rheumatic AR, without significant aortic stenosis or mitral regurgitation. The presence and location of SAM in the short-axis view were determined by M-mode echocardiography guided by two-dimensional echocardiography. The extent and direction of the regurgitant jet were decided by pulsed or two-dimensional Doppler echocardiography. SAM was observed in 21 (48%) of the 44 patients, and it was more frequently observed in patients with an etiology of aortic valve prolapse or annuloaortic ectasia than in those of other etiology (10/14 vs 10/30; p less than 0.05). Twenty-eight patients whose regurgitant jet was directed posteriorly and impinged on the mitral valve apparatus had a significantly higher incidence of SAM than did the other 16 patients (18/28 vs 3/16; p less than 0.01). In eight of 10 patients in whom the direction of the regurgitant jet could be precisely observed by two-dimensional Doppler echocardiography. SAM was observed at the place where a regurgitant jet was directed along the anterior mitral valve in the short-axis view. M-mode measurements (LVDd, LVDs, %FS, LVDd-LVDs) of the patients with SAM had greater values than those of patients without SAM.(ABSTRACT TRUNCATED AT 250 WORDS)     

Systolic anterior motion of the mitral valve. An unusual echocardiographic feature of mitral valve endocarditis

An unusual M-mode echocardiographic feature of mitral valve endocarditis is described: systolic anterior motion of the mitral valve, likely due to mitral valve vegetations, protruding during systole into the left ventricular outflow tract. The presence of mitral valve vegetation was confirmed at operation.     

The significance of systolic anterior motion (SAM) on the mitral valve echo pattern in hypertrophic cardiomyopathy

The systolic anterior motion (SAM) of valve structures in the mitral echogram in hypertrophic cardiomyopathy (HCM) has previously been considered to be anterior motion and re-opening of mitral valve leaflets, causing left ventricular outflow tract (LVOT) obstruction and mitral regurgitation. Fifteen patients with HCM underwent cardiac catheterisation and were also examined by M-scan and mechanical real-time B-scan techniques. In all patients SAM was seen during M-scan echocardiography. The mitral valve leaflets were visualised during the entire cardiac cycle during real-time B-scanning without showing any re-opening in systole. Thickened papillary muscles have been observed in 12 patients and prominent chordae tendineae moving in the opposite direction to the anterior mitral valve leaflet in 10 patients. Four patients with SAM did not show mitral regurgitation during left ventricular angiography. In two patients without fixed haemodynamic obstruction, a complete SAM touching the interventricular septum was observed with prolonged apposition in one case. These findings suggest that SAM is due to the motion of chordae tendineae and/or papillary muscles traversing the single dimensional ultrasonic beam in systole, thus producing single linear or multiple spotty echoes within SAM. The mechanism of the upward motion of the subvalvular mitral valve apparatus in systole appears to be due to forceful contraction of the apical left ventricular posterior wall. The observation of SAM in patients without HCM also indicates that its presence during single dimensional echocardiography is neither diagnostic nor specific for HCM, LVOT obstruction or mitral regurgitation, and contradicts the assumption that the anterior mitral valve leaflet plays a significant role in the mechanism of LVOT obstruction. The salient feature of all conditions associated with abnormal mitral subvalvular motion is hyperkinetic contraction of the apical left ventricular posterior wall. Hyperkinetic left ventricular ejection appears to be the main factor in the complex development of an LVOT gradient in hypertrophic cardiomyopathy.     

Systolic anterior motion of the mitral valve without asymmetric septal hypertrophy.

This report describes a patient with echocardiographic systolic anterior motion of the mitral valve causing the anterior mitral leaflet to contact the septum in systole. At necropsy a normal nonhypertrophied heart with normal-sized ventricular cavities and a normal outflow tract and mitral valve was found. Thus, asymmetric septal hypertrophy and abnormal mitral valvular placement are not requisites for systolic anterior motion of the mitral valve. During systole, a marked forward movement of the anterior mitral leaflet developed in our patient in the setting of hypovolemia and continuous intravenous administration of pressor drugs, suggesting, rather, that systolic anterior motion reflects a small, vigorously contracting ventricular cavity and that such dynamic subaortic obstruction is not pathognomonic of idiopathic hypertrophic subaortic stenosis.     

Systolic anterior motion (SAM) of the posterior mitral leaflet: left ventricular outflow tract obstruction in a patient without left ventricular hypertrophy

Systolic anterior motion (SAM) of the anterior mitral leaflet with mitral-septal contact was generally thought to be a major contributor to dynamic left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy. We report an interesting case of SAM of the posterior mitral leaflet in a patient without left ventricular hypertrophy, which led to dynamic left ventricular obstruction.     

Validation of a decision-making strategy for systolic anterior motion following mitral valve repair

Low cardiac output syndrome and hypotension are dreadful consequences of systolic anterior motion (SAM) after a mitral valve (MV) repair. The management of SAM in the operating room remains controversial. We validate a recently suggested two-step management method and classification of this complication. This was a teaching hospital-based observational study. We validated a novel two-step conservative management method, consisting in intravascular volume expansion and discontinuation of inotropic drugs (step 1), and increasing the afterload by ascending aorta manual compression while administering esmolol e.v. (step 2). We also validate a novel classification of SAM: easy-to-revert (responding to step 1), difficult-to-revert (responding to step 2), or persistent. Fifty patients had an easy-to-revert while 26 had a difficult-to-revert SAM; 4 patients had a persistent condition (promptly diagnosed through our decisional algorithm) and underwent an immediate second pump run to repeat the mitral repair surgery. We confirmed that SAM after a repair of a degenerative MV is common and validated a simple two-step conservative management method that allows to clearly identify those few patients who require immediate surgical revision.     

Body piercing: a rare cause of mitral valve endocarditis

Body piercing has become a way of life for many individuals. It represents freedom, as well as rebellion, and can provide shock value to the public. Often, it is used as a rite of passage from adolescence into adulthood, and can also provide a boost in self-esteem. However, body piercing may lead to non-infectious complications such as prolonged bleeding and keloid formation, while infectious complications include the transmission of blood-borne infections (e.g. human immunodeficiency virus, hepatitis B, C and D), as well as bacteremia through the site of piercing. Infective endocarditis in individuals with congenital heart defects has been identified after body piercing. Here, the first documented case is reported of mitral valve endocarditis in a previously fit and healthy young female following navel piercing.     

Systolic anterior motion of the mitral valve in the absence of asymmetric septal hypertrophy.

Asymmetric septal hypertrophy (ASH) is considered the unifying link in the spectrum of hypertrophic cardiomyopathies. ASH and mitral valve systolic anterior motion (SAM) are the two most important echocardiographic criteria for the diagnosis of idiopathic hypertrophic subaortic stenosis (IHSS). Ten patients found have SAM without ASH were studied. Septal thickness, thickening, and excursion were normal. Seven patients had left ventricular ejection times (LVET) measured before and after amyl nitrite inhalation. In six of them, corrected LVET increased by more than 40 msec. Four patients underwent diagnostic cardiac catheterization. Resting or provocable left ventricular outflow tract (LVOT) gradients were demonstrable in all four patients. The echocardiographic features in patients with SAM alone, ASH and SAM, and ASH alone were compared. compared. LVOT measurements in patients with SAM alone (2.2 +/- .4 cm) and ASH and SAM (2.1 +/- .5 cm) were similar and narrower than in patients with ASH alone (2.8 +/- .5 cm, P less than 0.001). Ejection fractions in patients with SAM alone (79 +/- 10%) were greater than in patients with ASH and SAM (66 +/- 16%, P less than 0.02) or ASH alone (60 +/- 15%, P less than 0.001). Thus, dynamic left ventricular outflow obstruction can exist in the absence of echocardiographic ASH. LVOT width and abnormal LV ejection dynamics may contribute to the LVOT obstruction with or without the presence of ASH.     

Systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy. A cross-sectional echocardiographic study

Different cross-sectional echocardiographic patterns of systolicanterior motion of the mitral valve (SAM) have been observedin patients with hypertrophic cardiomyopathy. Chordae tendineaeand/or the free edge of the mitral valve were seen to be involvedin some: SAM(c). The body of the mitral valve encroached uponthe left ventricular outflow tract in this movement in a secondgroup: SAM(v). Other patients did not show SAM. A study of 27patients was performed to investigate the relationship of thesepatterns of SAM to the subaortic gradient as well as the prevalenceand degree of mitral re gurgitation. The absence of SAM correlatedwith no obstruction and 29% prevalence of mitral re gurgitation.In SAM(c), the mean gradient was 10±10 mmHg. (0–35mmHg), and mitral regurgitation involved 36% of the patients.In SAM(v) the mean gradient found was 81 ±37 mmHg (20–150),and 67% had mitral regurgitation. In situations where mitralregurgitation was most prevalent its degree was greatest. Inconclusion: (1) chordal or leaflet participation in SAM is relevantto the presence and degree of obstruction: (2) leaflet involvementusually implies severe obstruction: (3) distortion of the mitralvalve apparatus may contribute to the genesis of mitral.