Motion of mitral apparatus in hypertrophic cardiomyopathy with obstruction.

Motion of the mitral apparatus in hypertrophic cardiomyopathy with obstruction was investigated by conventional single dimensional and multidimensional echocardiography. In systole, anterosuperior displacement of the posterior papillary muscle, failure of mitral valve closure, and anterior motion of both mitral leaflets were shown. The anterior leaflet was seen to impinge on the posterior papillary muscle but not on the interventricular septum in systole. The abnormality of the single dimensional mitral echogram, previously ascribed to systolic anterior motion of the mitral anterior leaflet, was found to be a complex of echoes from the chordae tendineae, the papillary muscle, and, furthest from the septum, the mitral anterior leaflet. It is concluded that systolic anterior motion of the mitral anterior leaflet is of smaller amplitude than others have suggested, and that obstruction to left ventricular outflow in hypertrophic cardiomyopathy is produced by systolic contact between the mitral anterior cusp and the posterior papillary muscle. The theory is put forward that displacement of the posterior papillary muscle above and in front of the mitral leaflets produces chordal slackening, and that it is displacement of the chordae tendineae by the blood flowing to the aortic root during left ventricular ejection, which is responsible for systolic anterior motion of the mitral leaflets.     

Real time observation of the echo source of systolic hump in hypertrophic obstructive cardiomyopathy with high speed ultrasono-cardiotomography.

The present study was undertaken to discuss the echo source of systolic hump in hypertrophic obstructive cardiomyopathy (HOCM) from a viewpoint of B-mode echocardiography. Cross-sectional images were obtained from 4 patients with HOCM using a Sonolayergraph of Toshiba, SSL-51H. This equipment is characterized by its high speed mechanical sector scanning and wider angle. Recordings were made with ordinary 35 mm camera or Polaroid in conjunction with 8 mm cinecamera. Our data showed that systolic hump in this lesion was not caused by anterior systolic movement of anterior mitral leaflet, but was emanated from the chordae tendineae attached to the anterior or posterior mitral leaflet. In systole, the anterior mitral leaflet moved backward for closure, while the chordae tendineae approached the bulged interventricular septum resulting in the formation of systolic hump.     

Initial results of combined anterior mitral leaflet extension and myectomy in patients with obstructive hypertrophic cardiomyopathy

Objectives. The purpose of this study was to describe the clinical and functional results of combined anterior mitral leaflet extension and myectomy in patients with hypertrophic obstructive cardiomyopathy.Background. Septal myectomy is the most commonly performed surgical procedure in patients with hypertrophic cardiomyopathy and left ventricular outflow tract obstruction. Because of the role of the mitral valve in creating the outflow tract gradient, mitral valve replacement or plication is performed in selected cases in combination with myectomy, often with better hemodynamic results than those of myectomy alone. Mitral valve leaflet extension, in which a glutaraldehyde-preserved autologous pericardial patch is used to enlarge the mitral valve along its horizontal axis, is a novel surgical approach in patients with hypertrophic obstructive cardiomyopathy.Methods. Eight patients with hypertrophic obstructive cardiomyopathy were treated with mitral leaflet extension and myectomy. Preoperative and postoperative data (New York Heart Association functional class, number of drugs prescribed, width of the interventricular septum, severity of mitral valve regurgitation, severity of systolic anterior motion of the mitral valve and outflow tract gradient) were compared with those of 12 patients undergoing myectomy alone.Results. Preoperative evaluation demonstrated that mitral regurgitation and systolic anterior motion of the mitral valve were more severe in the group undergoing mitral valve extension (p < 0.001 and p < 0.05, respectively). There were no deaths associated with either surgical procedure. Two patients, both treated by myectomy alone, died during the follow-up period. Postoperatively, patients treated with mitral valve extension had less mitral regurgitation (p < 0.005), less residual systolic anterior motion (p < 0.01), greater improvement in functional class (p = 0.05) and greater reduction in the number of drugs (p < 0.005) and in septal thickness (p < 0.05).Conclusions. Mitral leaflet extension in combination with myectomy is a promising new surgical approach that may provide superior results to those of myectomy alone. Further studies are needed to determine the clinical value of this procedure.     

Specificity of systolic anterior motion of anterior mitral leaflet for hypertrophic cardiomyopathy. Prevalence in large population of patients with other cardiac diseases.

The value of systolic anterior motion of the anterior mitral leaflet as a diagnostic marker for hypertrophic cardiomyopathy has been questioned because of its reported occurrence in other heart diseases. To determine the true specificity of systolic anterior motion for hypertrophic cardiomyopathy, 721 echocardiograms from patients with a wide variety of cardiac diseases were reviewed for its presence or absence under basal conditions. Systolic anterior motion of the anterior mitral leaflet was present in only 22 (3.0%) of the 721 patients, giving a specificity of 97 per cent. It was most common in patients with d-transposition of the great vessels (11 of 51, or 21%). With patients having transposition of the great vessels excluded from the analysis, the prevalence of systolic anterior motion of the anterior mitral leaflet was only 1.6 per cent (specificity 98%). Of note, eight of the 11 patients with systolic anterior motion of the anterior mitral leaflet and diseases other than transposition of the great vessels had disproportionate thickening of the ventricular septum, making it exceedingly rare in a patient population with normal septal-free wall thickness ratios (prevalence 0.4%; specificity 99%). Hence, while systolic anterior motion is not pathognomonic of hypertrophic cardiomyopathy, it was an uncommon finding in a large population of patients with a variety of cardiac diseases; when present in such patients systolic anterior motion of the anterior mitral leaflet is usually associated with disproportionate septal thickening.     

Hypertrophic cardiomyopathy in Friedreich's ataxia.

The cardiac findings in two sibs with Friedreich's ataxia are described. The clinical signs were suggestive of hypertrophic obstructive cardiomyopathy. During left heart catheterization a systolic pressure gradient across the left ventricular outflow tract could be provoked by an infusion of isoprenaline. Left ventricular angiocardiograms and echocardiograms showed gross thickening of the interventricular septum. In one patient a systolic anterior movement of the anterior leaflet of the mitral valve was seen. The importance of serial echocardiographic examination for patients with Friedreich's ataxia is emphasized.     

Hypertrophic cardiomyopathy in Friedreich's ataxia.

The cardiac findings in two sibs with Friedreich's ataxia are described. The clinical signs were suggestive of hypertrophic obstructive cardiomyopathy. During left heart catheterization a systolic pressure gradient across the left ventricular outflow tract could be provoked by an infusion of isoprenaline. Left ventricular angiocardiograms and echocardiograms showed gross thickening of the interventricular septum. In one patient a systolic anterior movement of the anterior leaflet of the mitral valve was seen. The importance of serial echocardiographic examination for patients with Friedreich's ataxia is emphasized.     

Unusual form of 'obstructive hypertrophic cardiomyopathy': unique contribution of comprehensive cardiovascular magnetic resonance

A 50-year-old male was referred for dyspnoea on exertion andsystolic murmur. The 12-lead ECG was normal. Transthoracic echocardiographyrevealed an obstructive hypertrophic cardiomyopathy (OHCM) witha 23 mm thick basal septum, systolic anterior motion of theanterior mitral leaflet, moderate mitral regurgitation, and70 mmHg dynamic intraventricular     

Acute mitral regurgitation due to ruptured chordae tendineae in a patient with hypertrophic obstructive cardiomyopathy: a case report

A 63-year-old woman had been followed up for hypertrophic obstructive cardiomyopathy with 85 mmHg of left ventricular outflow tract pressure gradient over 7 years. She was hospitalized because of acute dyspnea and syncope. On admission, echocardiography revealed severe mitral regurgitation with ruptured chordae tendineae at the medial scallop of the posterior mitral leaflet. Mitral valve replacement was successfully performed and her symptoms improved to 28 mmHg of left ventricular outflow tract pressure gradient. In patients with hypertrophic obstructive cardiomyopathy, elevated left ventricular systolic pressure and systolic anterior motion of the mitral leaflets may lead to mucoid degeneration in the chordae tendineae. Rupture of the mitral chordae tendineae should be considered in the differential diagnosis of acutely deteriorated mitral regurgitation in patients with hypertrophic obstructive cardiomyopathy, because this is a rare but critical complication.     

Mitral regurgitation due to ruptured chordae tendineae in patients with hypertrophic obstructive cardiomyopathy.

Mitral valve regurgitation in association with hypertrophic obstructive cardiomyopathy is usually caused by the systolic anterior motion of the anterior mitral leaflet. Recently, five patients were encountered with hypertrophic obstructive cardiomyopathy who had mitral regurgitation due to ruptured chordae tendineae. The diagnosis was confirmed in all patients during operation for left ventricular septal myectomy-myotomy (Morrow procedure). Preoperative identification of ruptured chordae tendineae as the cause of mitral regurgitation was established by transesophageal echocardiography in the three most recent cases. All patients had successful septal myectomy-myotomy for relief of left ventricular outflow obstruction, and mitral valve competence was restored by valve repair rather than by prosthetic valve replacement. The clinical course of these patients illustrates important management considerations as well as the utility of transesophageal echocardiography for diagnosis. Chordal rupture should be considered in the differential diagnosis of mitral regurgitation in patients with hypertrophic obstructive cardiomyopathy, especially in those with acute hemodynamic deterioration.     

Dynamic left ventricular outflow tract obstruction and systolic anterior motion of the mitral valve in the absence of asymmetric septal hypertrophy

Systolic anterior motion of the anterior mitral valve leaflet and asymmetric septal hypertrophy are the principal components of the dynamic subaortic stenosis in hypertrophic obstructive cardiomyopathy. Mitral valve systolic anterior motion without septal hypertrophy or left ventricular outflow tract obstruction has been described, but asymmetric septal hypertrophy is supposedly a consistent feature of dynamic subaortic stenosis. We describe two patients with syncope, chest pain and the typical systolic murmur of hypertrophic subaortic stenosis whose echocardiograms showed mitral valve systolic anterior motion but not asymmetric septal hypertrophy. Normal septal thickness on echo was confirmed by intravenous indocyanine green to identify the right septal endocardium. At catheterization, left ventricular outflow tract gradients were provoked, and neither patient had interventricular septal hypertrophy on biventricular cineangiography. These findings in two cases suggest that mitral valve systolic anterior motion can be the only definable anatomic abnormality associated with symptomatic dynamic left ventricular outflow tract obstruction and that asymmetric septal hypertrophy is not a necessary component of this condition.     

Alcohol ablation of the interventricular septum in a patient with hypertrophic obstructive cardiomyopathy complicated by an increase in the pressure gradient in the left ventricular outflow tract. A case report

A case of a 70 year old female with hypertrophic obstructive cardiomyopathy who underwent alcohol ablation of the interventricular septum, is presented. Following the procedure, the pressure gradient decreased from 120 mmHg to 80 mmHg. However, 30 minutes after ablation the patients developed hypotension and pulmonary oedema. Echocardiography revealed a significant systolic anterior movement of the anterior leaflet of the mitral valve and elevated pressure gradient up to 200 mmHg. The patient underwent urgent surgery (myectomy), followed by the mitral valve replacement with a favourable outcome.     

Patterns of systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy: assessment by two-dimensional echocardiography

A variety of patterns of systolic anterior motion (SAM) of the mitral valve were identified by realtime, 2-dimensional echocardiography in 62 patients with hypertrophic cardiomyopathy. In 36 patients (58%), both the anterior and posterior mitral leaflets appeared to participate importantly in SAM, although the anterior leaflet actually contacted or most closely approached the ventricular septum during systole because of its anterior anatomic position. In 19 patients (31%), SAM was produced selectively by the posterior mitral leaflet. In only 6 patients (10%) was the anterior leaflet alone responsible for SAM. In just 1 patient did the chordae tendineae appear to be primarily responsible for the SAM. In 51 patients (82%), only the distal portion of the anterior or posterior mitral leaflet (and possibly the attached proximal chordae tendineae) approached or contacted the septum in systole; in 10 patients both the body and tip regions of the anterior leaflet produced mitral-septal apposition. Hence, in obstructive hypertrophic cardiomyopathy, (1) the morphologic structures responsible for moderate to severe SAM are not identical in all patients, and a variety of patterns of SAM occur; (2) the posterior mitral leaflet plays an important role in SAM in almost 90% of patients, either by producing SAM alone (31%) or by moving anteriorly in concert with the anterior leaflet (58%); (3) SAM produced selectively by the anterior mitral leaflet is relatively uncommon; and (4) SAM is usually produced primarily by the distal portions of the mitral leaflets (with or without the attached chordae tendineae).     

Prevalence of systolic anterior motion of the mural (posterior) leaflet of the mitral valve in hypertrophic cardiomyopathy: an echocardiographic study

Cross-sectional echocardiography was used to identify systolic anterior motion of the mural (posterior) leaflet of the mitral valve from a group of 53 patients with hypertrophic cardiomyopathy. This type of systolic anterior motion was identified in parasternal long axis, apical four-chamber and/or long-axis cross-sections and was characterized by an elongation of the mural leaflet and an abnormal coaptation with the aortic (anterior) leaflet. At end-diastole, the aortic leaflet coapted at the basal or mid portion of the mural leaflet, leaving its distal "residual" segment in the left ventricle. Subsequently, during systole this "residual" segment approached or touched the ventricular septum. Systolic anterior motion of the mural leaflet was present in 6 (12%) of our patients with hypertrophic cardiomyopathy. Lengthening of the leaflet and an abnormal coaptation were associated with increased thickening of the posterior wall of the left ventricle and narrowing of the left ventricular outflow tract. All these elements contribute to the occurrence of systolic anterior motion and left ventricular tract obstruction.     

Hypertrophic cardiomyopathy: Recent observations regarding the specificity of three hallmarks of the disease: Asymmetric septal hypertrophy,septal disorganization and systolic anterior motion of the anterior mitral leaflet

Neither asymmetric septal hypertrophy (ASH), marked cell disorganization in the ventricular septum nor systolic anterior motion of the anterior mitral leaflet (SAM) is pathognomonic of hypertrophic Cardiomyopathy. However, each is uncommonly found in patients with other cardiac disorders and is therefore a highly specific hallmark of hypertrophic cardiomyopathy. Disproportionate septal thickening does occur in about 10 percent of older children and adults with various acquired or congenital heart diseases. In these patients it usually appears to be secondary to the underlying hemodynamic state. However, disproportionate septal thickening is the usual finding in the developing embryonic and fetal heart and it is relatively common (prevalence rate about 25 percent) in normal neonates and infants with congenital heart disease.Likewise, although cell disorganization in the ventricular septum may occur with other cardiac malformations, extensive disorganization is present in about 90 percent of patients with hypertrophic cardiomyopathy and in only about 5 percent of patients with other cardiac diseases. Finally, systolic anterior motion of the anterior mitral leaflet is characteristic of those patients with hypertrophic cardiomyopathy who have obstruction to left ventricular outflow, and it rarely appears (prevalence rate about 3 percent) under basal conditions in other hemodynamic states or cardiac diseases. Hence, in analyses comprising over 1,600 patients the specificity of asymmetric septal hypertrophy, marked septal disorganization and systolic anterior motion of the anterior mitral leaflet was at least 90 percent (90, 93 and 97 percent, respectively). Furthermore, the sensitivity of extensive septal disorganization for hypertrophic cardiomyopathy was 90 percent.The data currently available therefore suggest that the vast majority of patients fulfilling the basic anatomic criteria for hypertrophic cardiomyopathy (that is, a hypertrophied nondilated left ventricle in the absence of a cardiac or systemic disease that itself could produce left ventricular hypertrophy) have a distinct disease entity with diverse clinical manifestations. The majority of such patients appear to have a genetically transmitted disease, but it is not known precisely what proportion of these patients have phenotypically similar but etiologically separate disease entities.     

Left ventricular outflow tract obstruction due to systolic anterior motion of the anterior mitral leaflet in patients with concentric left ventricular hypertrophy

Patients with hypertrophic cardiomyopathy (i.e., asymmetric septal hypertrophy) may show obstruction to left ventricular outflow under basal conditions or with provocative maneuvers. The presence of dynamic left ventricular outflow tract obstruction in patients with concentric ventricular wall thickening (but without abnormalities of the aortic valve) has been less well appreciated. Clinical and morphologic features of five patients with nondilated left ventricles and with left ventricular outflow obstruction are presented. In each patient peak systolic pressure gradients between left ventricle and systematic artery were measured at cardiac catheterization and ranged from 60-140 mm Hg under basal conditions or with provocation. Each patient had echocardiographically documented systolic anterior motion of the anterior mitral leaflet, which was apparently responsible for the outflow obstruction, and concentric left ventricular wall thickening (septal-free wall thickness ratio of less than 1.3). Two of the five patients had evidence of genetically transmitted hypertrophic cardiomyopathy, as evidenced by disorganized muscle cells in the ventricular septum or asymmetric septal hypertrophy in first degree relatives. Hence, left ventricular outflow tract obstruction associated with systolic anterior motion of the anterior mitral leaflet may occur in some patients with concentric left ventricular hypertrophy who do not have typical hypertrophic cardiomyopathy.     

Markedly abnormal mitral valve motion without simultaneous intraventricular pressure gradient due to uneven mitral-septal contact in idiopathic hypertrophic subaortic stenosis

Although echocardiographic analysis reliably diagnoses idiopathic hypertrophic subaortic stenosis by detection of systolic forward anterior mitral valve motion and estimates severity of obstruction by the timed mitral encroachment of the interventricular septum, echographic stenosis may occur without hemodynamic obstruction or pressure gradient across the left ventricular outflow tract. Demonstration and mechanism of this apparent inconsistency are described in three patients with a previously unrecognized state of Idiopathic hypertrophic subaortic stenosis characterized by marked systolic forward movement of the anterior mitral valve without a simultaneous intraventricular pressure gradient, resulting from uneven septal apposition by the anterior leaflet. Echographic obstruction indexes (40, 34 and 31) during cardiac catheterization in the three patients were predictive of respective peak gradients of 37, 25 and 20 mm Hg. The horizontal nonparallel mitralseptal contact consistent with severe systolic forward movement of the anterior mitral valve in the absence of hemodynamic stenosis is believed to be caused by markedly forward displacement of the anterior papillary muscle, so that its chordae tendineae produce greater tension on the posteromedial aspect of the anterior mitral valve. Thereby the posterior portion of the leaflet is pulled forward more than its anterior side, allowing marked systolic forward anterior mitral valve motion without a pressure gradient in idiopathic hypertrophic subaortic stenosis.     

Nongenetically transmitted disproportionate ventricular septal thickening associated with left ventricular outflow obstruction.

Clinical, haemodynamic, and morphological features are described in 2 patients with disproportionate ventricular septal thickening, left ventricular outflow obstruction with systolic anterior motion of the anterior mitral leaflet, and either acquired or congenital heart disease. The disproportionate septal thickening in these patients appeared to be secondary to their underlying cardiac disease rather than a manifestation of genetically transmitted hypertrophic cardiomyopathy. One patient with combined aortic and mitral stenosis had severe systolic anterior motion of the anterior mitral leaflet and a residual large systolic pressure gradient between left ventricle and systemic artery after aortic valve replacement. In this patient the systolic anterior motion was evident in the presence of mitral valve stenosis. The other patient with mild aortic stenosis and a previously repaired coarctation of the aorta also had mild systolic anterior motion and a small subaortic systolic pressure gradient. Hence, these 2 patients demonstrate that disproportionate septal thickening secondary to acquired or congenital heart disease may be associated with left ventricular outflow obstruction and systolic anterior motion of the anterior mitral leaflet.     

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.     

Nongenetically transmitted disproportionate ventricular septal thickening associated with left ventricular outflow obstruction.

Clinical, haemodynamic, and morphological features are described in 2 patients with disproportionate ventricular septal thickening, left ventricular outflow obstruction with systolic anterior motion of the anterior mitral leaflet, and either acquired or congenital heart disease. The disproportionate septal thickening in these patients appeared to be secondary to their underlying cardiac disease rather than a manifestation of genetically transmitted hypertrophic cardiomyopathy. One patient with combined aortic and mitral stenosis had severe systolic anterior motion of the anterior mitral leaflet and a residual large systolic pressure gradient between left ventricle and systemic artery after aortic valve replacement. In this patient the systolic anterior motion was evident in the presence of mitral valve stenosis. The other patient with mild aortic stenosis and a previously repaired coarctation of the aorta also had mild systolic anterior motion and a small subaortic systolic pressure gradient. Hence, these 2 patients demonstrate that disproportionate septal thickening secondary to acquired or congenital heart disease may be associated with left ventricular outflow obstruction and systolic anterior motion of the anterior mitral leaflet.     

Transesophageal Doppler echocardiography in obstructive hypertrophic cardiomyopathy: clarification of pathophysiology and importance in intraoperative decision making.

To better understand the pathophysiology of obstruction of left ventricular outflow in hypertrophic cardiomyopathy and to determine the value of intraoperative transesophageal Doppler echocardiography in decision making, 32 consecutive patients undergoing ventriculomyectomy were assessed. The mean preoperative left ventricular outflow gradient was 83 +/- 39 mm Hg and the mean basal septal width was 24 +/- 6 mm. Compared with transesophageal findings in 10 normal control subjects, the mitral leaflets were longer and the coaptation point was abnormal in the patients with obstructive hypertrophic cardiomyopathy (anterior and posterior leaflet lengths in the patients were 31 +/- 4 vs. 22 +/- 3 mm in the control group [p less than 0.00001] and 20 +/- 2 vs. 15 +/- 3 mm in the control group [p less than 0.00001]). The coaptation point in the patient group was in the body of the leaflets at a mean of 9 +/- 2 mm from the anterior leaflet tip, whereas it was at or within 3 mm of the leaflet tip in the normal group. During early systole, the distal third to half of the anterior mitral leaflet angled sharply anteriorly and superiorly (systolic anterior motion), resulting in leaflet-septal contact and incomplete mitral leaflet coaptation in mid-systole. This caused the formation of a funnel, composed of the distal parts of both leaflets, that allowed a jet of posteriorly directed mitral regurgitation to occur in mid- and late systole. The sequence of events in systole was eject/obstruct/leak. Transesophageal echocardiography was also helpful in planning the extent of the resection, assessing the immediate result and excluding important complications. In successful cases, the post-myectomy study showed 1) a dramatic thinning of the septum, with widening of the left ventricular outflow tract to a width similar to that in the normal subjects, 2) resolution of systolic anterior motion and the left ventricular outflow tract color mosaic, and marked reduction or abolition of mitral regurgitation despite persistence of abnormal mitral leaflet length and an abnormal mitral leaflet coaptation point. The routine use of transesophageal echocardiography in patients undergoing surgical myectomy for the treatment of obstructive hypertrophic cardiomyopathy is recommended.