Angiographic anatomy of the left ventricle and mitral valve in idiopathic hypertrophic subaortic stenosis

Production of left ventricular cavitary obliteration in normal man

To determine whether left ventricular cavitary obliteration (a finding previously described only in hypertrophic states) can be induced in normal subjects, 16 patients without coronary artery disease or clinical evidence of hypertrophic obstructive cardiomyopathy were studied during cardiac catheterization. Resting left ventricular and aortic pressures and left ventriculography were repeated during the strain phase of Valsalva maneuver after administration of amyl nitrite. Cavitary obliteration during normal sinus rhythm was defined as disappearance of the sinus portion of the left ventricle during systole, and graded as absent, partial or total. Patients were placed into two groups on the basis of qualitative analysis of the resting left ventriculogram: the 10 patients in group A had normal left ventriculograms and the six patients in group B had hyperkinetic left ventricles. During the left ventriculogram done with amyl nitrite and Valsalva, left ventricular volumes in both decreased dramatically, from 69 ml/m2 to 43 ml/m2 (p less than 0.001) and ejection fraction increased from 70% to 82% in group A (p less than 0.01). None of the patients in group A had evidence of cavitary obliteration at rest, but eight developed total and two developed partial cavitary obliteration with the second ventriculogram. Three patients in group B had partial or complete cavitary emptying at rest and all developed total cavitary obliteration with provocation. Pressure gradients between left ventricle and aorta were produced in two group A patients and three group B patients. Thus, cavitary obliteration can be produced in normal left ventricles by manipulation of loading conditions.

Arrhythmia in hypertrophic cardiomyopathy. I: Influence on prognosis

In order to examine the association between arrhythmia and subsequent prognosis, 72-hour ambulatory electrocardiographic monitoring was performed in 86 unselected patients with hypertrophic cardiomyopathy. During monitoring 23 patients experienced at least one episode of supraventricular tachycardia and 24 had ventricular tachycardia (of whom 10 had more than three episodes). The patients were then followed for a mean of 2.6 years (range one to four). Seven patients died suddenly. Of these, five had exhibited multiform and paired ventricular extrasystoles and ventricular tachycardia. These arrhythmias were significantly associated with sudden death whereas supraventricular arrhythmias were not. The patients who died suddenly were older and had experienced more symptoms than the survivors, and three had a family history of hypertrophic cardiomyopathy and sudden death. This experience provides the basis for the assessment of treatment in patients with hypertrophic cardiomyopathy and serious ventricular arrhythmia.

Prognosis in hypertrophic cardiomyopathy: role of age and clinical, electrocardiographic and hemodynamic features

Retrospective analysis of the clinical course of 254 patients with hypertrophic cardiomyopathy, followed up for 1 to 23 years (mean 6), disclosed that 58 had died, 32 of them suddenly. The 196 survivors were compared with the 32 patients who died suddenly and with the 38 who died suddenly or with heart failure. The combination of young age (14 years or less), syncope at diagnosis, severe dyspnea at last follow-up and a family history of hypertrophic cardiomyopathy and sudden death best predicted sudden death (false negative rate 30 percent, false positive rate 27 percent). A "malignant" family history was associated with poor prognosis, particularly in the younger patients; a family history of hypertrophic cardiomyopathy without sudden death was more frequent in the survivors (12 percent) than in the dead (5 percent). Patients who had a diagnosis in childhood were usually asymptomatic, had an unfavorable family history and a 5.9 percent annual mortality rate. In those aged 15 to 45 years at diagnosis, there was a 2.5 percent annual mortality rate and syncope was the only prognostic feature. Among those diagnosed between age 45 and 60 years, dyspnea and exertional chest pain were more common in the patients who died, and the annual mortality rate was 2.6 percent. Poor prognosis was better predicted by the history at the time of diagnosis and by changes in symptoms during follow-up than by an electrocardiographic or hemodynamic measurement.

Dynamics of left ventricular ejection in obstructive and nonobstructive hypertrophic cardiomyopathy

The purpose of this study was to examine the dynamics of left ventricular ejection in patients with obstructive and nonobstructive hypertrophic cardiomyopathy (HCM). 30 patients with HCM and 29 patients with no evidence of cardiovascular disease were studied during cardiac catheterization. Using a single multisensor catheter, electromagnetically derived ascending aortic flow velocity and high fidelity left ventricular and aortic pressures were recorded during rest (n = 47) and provocative maneuvers (n = 23). Dynamic ventricular emptying during rest was also analyzed with frame-by-frame angiography (n = 46). Left ventricular outflow was independently derived from both flow velocity and angiographic techniques. The HCM patients were subdivided into three groups: (I) intraventricular gradients at rest (n = 9), (II) intraventricular gradients only with provocation (n = 12), and (III) no intraventricular gradients despite provocation (n = 9). During rest, the percentage of the total systolic ejection period during which forward aortic flow existed was as follows (mean +/- 1 SD): group I, 69 +/- 17% (flow), 64 +/- 6% (angio); group II, 63 +/- 14% (flow), 65 +/- 6% (angio); group III, 61 +/- 16% (flow), 62 +/- 4% (angio); control group, 90 +/- 5% (flow), 86 +/- 9% (angio). No significant difference was observed between any of the HCM subgroups, but compared with the control group, ejection was completed much earlier in systole independent of the presence or absence of intraventricular gradients. These results suggest that "outflow obstruction," as traditionally defined by the presence of an abnormal intraventricular pressure gradient and systolic anterior motion of the mitral valve, does not impede left ventricular outflow in HCM.

Echocardiographic source of early anterior systolic motion in late systolic mitral valve prolapse

The echocardiographic features of patients with parachute mitral valve have revealed the combination of an early systolic movement of the mitral valve and late systolic prolapse. Cross-sectional echocardiographic and angiographic studies showed that the early systolic anterior motion was produced by the presence of a flail scallop of the anterior mitral leaflet in the left ventricular outflow tract.

Diastolic movement of mitral valve in hypertrophic cardiomyopathy. An echocardiographic study

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Idiopathic hypertrophic subaortic stenosis in the young

Thirty-six young patients with idiopathic hypertrophic subaortic stenosis were studied. Twenty-seven patients were male and 9 female, and their mean age was 11.3 years (range 5 months to 20 years). Twenty-three patients (64 percent) had symptoms, the most common being dyspnea, angina and syncope. Diagnostic difficulties were encountered frequently in younger patients, especially those with right heart involvement, and in asymptomatic patients with murmurs suggestive of other cardiac defects. Patients were classified retrospectively into three groups on the basis of management. The first group consisted of 16 patients who were operated on; 4 of these patients died, 1 operatively and 3 suddenly late postoperatively (at 1.6, 2 and 10 years). The 12 long-term survivors (average follow-up period 6.2 years) have had good relief of symptoms. The second group comprised seven patients treated with propranolol; none of these died. The 13 patients in the third group received no therapy; 7 of these patients died, 6 suddenly and 1 from congestive cardiac failure. Idiopathic hypertrophic subaortic stenosis is a serious disorder that may present at any age and that may be difficult to diagnose. All patients with this disorder should be treated with propranolol; surgical intervention, although it does not totally abolish the risk of sudden death, appears to offer symptomatic improvement in most cases over a long-term follow-up period.

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.

Echocardiographic diagnosis and evaluation of cardiomyopathies: idiopathic hypertrophic subaortic stenosis, Chagas' heart disease and endomyocardial fibrosis

Echocardiographic investigations on patients with hypertrophic cardiomyopathy with obstruction have been detailed and compared with the changes found in sixty patients with chronic Chagas' 'cardiomyopathy'. These changes are similar to those encountered in congestive cardiomyopathy. Endomyocardial fibrosis is rare in Venezuela, but six patients have been found in that country and the echocardiographic changes in one of these patients has been included in this study.

Coexisting right and left hypertrophic subvalvular stenosis and fixed left ventricular outflow obstruction due to aortic valve stenosis

A case of fixed left ventricular outflow tract obstruction due to aortic valve stenosis coexisting with right- and left-sided subvalvular hypertrophic stenosis is documented with hemodynamic data, angiograms, echocardiograms and findings at surgery. Histologic examination of the septal muscle with light and electron microscopy revealed hypertrophy of the muscle but none of the characteristics of idiopathic hypertrophic subaortic stenosis. Septal hypertrophy with subvalvular obstruction can occur secondary to left ventricular pressure overload due to fixed left ventricular outflow tract obstruction and is not always the chance occurrence of two separate diseases.

Tunnel subaortic stenosis: left ventricular outflow tract obstruction produced by fibromuscular tubular narrowing

The clinical and morphologic features of tunnel subaortic stenosis, an unusual form of obstruction to left ventricular outflow, are described in 11 patients. Although patients with tunnel subaortic stenosis demonstrate a variety of cardiovascular malformations, the most characteristic anatomic feature is fibromuscular tubular narrowing of the outflow tract that remains relatively unchanged during the cardiac cycle. The aortic anulus was abnormally small in six of the 11 patients, including one who also had a hypoplastic ascending aorta. Evidence of a small mitral orifice was present in two patients, and two other patients had asymmetric septal hypertrophy. Although operation was successful in significantly reducing the outflow gradient in two of the seven operated patients, all seven patients had gradients of 50 mm Hg or more at the most recent postoperative evaluation. Three patients (two with previous operation) died suddenly; each of these patients had mild or no symptoms. Because of the apparent ineffectiveness of current operative methods in patients with tunnel subaortic stenosis, it is important to differentiate this condition from obstructions to left ventricular outflow.

B-scan ultrasonography in idiopathic hypertrophic subaortic stenosis. Study of left ventricular outflow tract and mechanism of obstruction

Studies were made with standard time motion and B-scan echocardiography on 48 patients including 5 with idiopathic hypertrophic subaortic stenosis (hypertrophic obstructive cardiomyopathy), undergoing diagnostic cardiac catheterization. The dimensions of the left ventricular outflow (O) and inflow (I) tracts were measured on the B-scan images. The outflow tract was significantly narrowed in idiopathic hypertrophic subaortic stenosis at both end-systole (1-1+/-0-1 cm) and end-diastole (1-3+/-0-1 cm) when compared with the average width in other patients (2-6+/-0-1 and 3-0+/-0-1 cm, at end-systole and end-diastole, respectively) (P less than 0-001) or normal subjects (2-4+/-0-3 and 2-9+/-0-2 cm) (P less than 0-01). Furthermore, the O/I ratio differed significantly in idiopathic hypertrophic subaortic stenosis (0-5+/-0-1 at end-systole and 0-6+/-0-1 at end-diastole) from that in all other groups (1-4+/-0-1 at both end-systole and end-diastole) (P less than 0-005). There was no appreciable change in the width of the outflow tract from mid- to end-systole in the two patients in whom this was examined. The data support the contention that the anterior leaflet of the mitral valve assumes an abnormally anterior position in idiopathic hypertrophic subaortic stenosis. Though the systolic anterior movement of the tip of the anterior leaflet of the mitral valve shown by M-mode echocardiography could not readily be confirmed with B-scans, we believe that the narrowed outflow tract found in the present investigation contributes to the obstruction that occurs in this disease. We suggest that this outflow tract narrowing is probably caused by hypertrophy of the ventricular septum which in itself contributes to the narrowing, but which also displaces the papillary muscles and thus produces abnormal traction on the mitral valve and striking anterior displacement of the valve apparatus.

Echocardiographic spectrum of hypertrophic cardiomyopathy

Echocardiographic patterns in 15 patients with hypertrophic cardiomyopathy were compared with those in 30 healthy persons. Correlations with angiocardiographic data indicated that most of the anatomical abnormalities in hypertrophic cardiomyopathy can be assessed reliably by echocardiography. These include abnormal mitral valve motion, a reduction of the anteroposterior dimension of the left ventricular outflow tract and of the left and right ventricular cavities, increased thickness of the interventricular septum and the posterior left ventricular wall. Comparision of the haemodynamic and echocardiographic data showed that some degree of abnormal mitral valve motion during systole may occur in the absence of left ventricular outflow tract obstruction. On the other hand, it need not always be present with left ventricular outflow tract obstruction. Other, hitherto unrecognized, abnormalities in hypertrophic cardiomyopathy detected by this technique were: (1) Aortic valve regurgitation in three out of nine patients with evidence of left ventricular cutflow tract obstruction at cardiac catheterization. (2) Left ventricular inflow tract obstruction at the mitral valve level associated with gross septal hypertrophy (five cases). (3) Abnormal forward displacement of the posterior mitral valve leaflet and of the chordae tendineae during systole in 10 patients, in seven of whom there was confirmatory angiocardiographic evidence. Seven patients with miscellaneous cardiac disorders are described in whom asymmetric septal hypertrophy was revealed by echocardiography. In one of these patients coexisting hypertrophic cardiomyopathy was excluded histologically; thus asymmetrical septal hypertrophy is not confined to patients with hypertrophic cardiomyopathy.

Pathological features of hypertrophic obstructive cardiomyopathy (HOCM) in the elderly

The pathological findings and available clinical data in 15 necropsy cases of HOCM, aged over 61 years, are reported. Three patients were in the eighth decade and 4 in the ninth; 8 were women. Five presented as sudden death, 2 died in congestive cardiac failure, and 7 died of unrelated conditions and HOCM was an apparently incidental postmortem finding. Compared with cases under 60 years, the hearts of the elderly patients were heavier and less likely to show typical asymmetrical hypertrophy, the free wall of the left ventricle also being thickened in two-thirds of the cases over 60 years. Most of the elderly cases showed a distinctive band of fibrous thickening over the upper part of the interventricular septum. This lesion had a "mirror image" relation to the lower part of the aortic surface of the anterior mitral cusp, with the histological features of a friction lesion. It appears to be a morphological expression of the systolic contact of anterior mitral cusp and interventricular septum seen on cineangiography and thus diagnostic of HOCM. Once formed, the fibrous band appears to persist even if the obstructive element disappears. It is, therefore, a valuable diagnostic feature indicating a diagnosis of HOCM in an age group where the morphology is usually not the classical asymmetrical form and in which this diagnosis is usually not considered.

Mechanism of left ventricular outlfow obstruction in patients with obstructive asymmetric septal hypertrophy (idiopathic hypertrophic subaortic stenosis)

Left ventricular outflow obstruction in patients with idiopathic hypertrophic subaortic stenosis or obstructive asymmetric septal hypertrophy is due to abnormal forward motion during systole of the anterior mitral leaflet. To determine why some patients with this disease hav left ventricular outflow obstruction whereas others do not, we studied a large number of patiens with assymetric septal hypertrophy using both one- and two-dimensional echocardiography. In 100 patients with asymmetric septal hypertrophy and 22 normal subjects, mitral valve position at the onset of systole was quantitated by measuring the distance from the ventricular septum to the mitral valve and the distance from the mitral valve to the posterior left ventricular wall. None of the normal subjects and only 3 (6 percent) of 51 patients with nonobstructive asymmetric septal hypertrophy had a septal-mitral valve distance of less than 20 mm compared with 23 (66 percent) of 35 patients with obstructive asymmetric septal hypertrophy. Moreover, the mitral valve at the onset of systole was actually positioned forward in the left ventricular activity. Two-dimensional studies in 11 patients with obstructive asymmetric septal hypertrophy revealed that contraction of the malaligned papillary muscles did not cause the abnormal forward mitral valve motion. We propose that the left ventricular outflow obstruction in patients with obstructive asymmetric septal hypertrophy occurs as a result of two factors: (1) narrowing of the left ventricular outflow tract at the onset of systole, and (2) hydrodynamic forces generated by contraction on the left ventricle.

Pathological features of hypertrophic obstructive cardiomyopathy

The macroscopic features of hypertrophic obstructive cardiomyopathy are variable. The most easily recognized picture is of disproportionate and asymmetrical left ventricular hypertrophy with a small ventricular volume. Symmetrical ventricular hypertrophy also occurs and dilatation of the ventricular cavity may lead to a configuration more usually associated with congestive cardiomyopathy. Papillary muscle involvement leads to a bullet shape, often retained even when the ventricle dilates. Eighteen of the hearts showed a distinctive band of fibrous thickening below the aortic valve. This was a mirror image of the free edge of the anterior mitral cusp, had the microscopic features of an endocardial friction lesion, and was clearly the morphological expression of the systolic contact between cusp and septum seen on cineangiography. This band is characteristic of hypertrophic obstructive cardiomyopathy; it was more common in older patients and is of particular diagnostic value in cases with symmetrical hypertrophy, including those with dilated ventricular cavities. Sudden death was the commonest presentation in the younger cases but in several cases over 60 years at death hypertrophic obstructive cardiomyopathy was an incidental necropsy finding.

Analysis of symptomatic course and prognosis and treatment of hypertrophic obstructive cardiomyopathy

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Atrial fibrillation in patients with idiopathic hypertrophic subaortic stenosis

Atrial fibrillation occurred in 16 (10%) of 167 patients with idiopathic hypertrophic subaortic stenosis. The clinical and haemodynamic findings in these 16 patients are presented. Atrial fibrillation appeared late in the course of the disease, and its occurrence did not seem to be related to the severity of left ventricular outflow obstruction or to the amount of associated mitral regurgitation. In each patient the onset of the arrhythmia was accompanied by severe clinical deterioration, which often necessitated urgent medical treatment. Digitalis was administered to all 16 patients with subsequent clinical improvement in 15. Electrical cardioversion was uniformly successful in restoring sinus rhythm, but atrial fibrillation usually recurred. In each of 8 patients catheterized during atrial fibrillation, cardiac output was strikingly low (average, 1.9 l./min./m.(2)), whereas it was normal in 10 of 13 patients studied in sinus rhythm. The duration of follow-up from the onset of atrial fibrillation has averaged 5 years, and 3 of the 16 patients have died of causes related to their heart disease. Four have suffered cerebral emboli. Only 5 patients are now in stable sinus rhythm; in general, they are less symptomatic than the patients in whom atrial fibrillation has recurred.The unusually severe clinical deterioration at the onset of atrial fibrillation and the low cardiac output measured during catheterization are thought to be related to the loss of the important contribution to ventricular filling of atrial systole in patients with poorly compliant ventricles, and to the effect of an irregular ventricular rhythm on the variable nature of the outflow obstruction.

Ultrasound in the diagnosis and evaluation of therapy of idiopathic hypertrophic subaortic stenosis

Twenty patients with idiopathic hypertrophic subaortic stenosis (IHSS) were studied with cardiac echography. Eight of these patients were studied during left heart catheterization. The echographic pattern of mitral valve motion during systole was altered in a characteristic manner when hemodynamically significant left ventricular outflow obstruction was present in the eight patients studied at catheterization. The abnormal systolic pattern was abolished by spontaneous loss of outflow obstruction or loss of obstruction induced by beta-adrenergic blockade. An abnormal systolic mitral valve pattern was seen on the echogram in 17 of the 20 patients with proven IHSS. The abnormal pattern was lost after the institution of chronic propranolol therapy in one patient. The three patients not showing an abnormal systolic pattern were also taking propranolol. The pattern of mitral valve motion during diastole indicated an impaired rate of left ventricular filling. The basic abnormalities and variability in the degree of abnormality seen with echography of the left ventricular outflow tract are consistent with the proposed anatomy and pathophysiology of IHSS.

Physical signs in differential diagnosis of left ventricular obstructive cardiomyopathy

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Ultrasound localization of left ventricular outflow obstruction in hypertrophic obstructive cardiomyopathy

Simultaneous recordings of reflected ultrasound from the anterior mitral leaflet and left ventricular outflow, the ECG, the phonocardiogram, and a recording of the carotid artery pulse were obtained in six patients with hypertrophic obstructive cardiomyopathy. Abnormal sharp systolic anterior movement (SAM) of the mitral leaflet was observed. This movement began with the onset of ventricular ejection and reached a peak with the initial peak in the arterial pulse. The leaflet was apposed to the interventricular septum up to 60% of the ejection period. In the latter part of systole as the mitral leaflet moved away from the interventricular septum, the arterial pulse showed a second systolic wave. Onset of SAM coincided with onset of the systolic murmur. Spontaneous variations in amplitude of SAM coincided with alterations in contour of the arterial pulse and in the intensity of the murmur. Administration of methoxamine to four patients resulted in disappearance of SAM. In one patient following surgery, the SAM of the mitral leaflet was noted only in the post-ectopic beats. This specific abnormality of mitral leaflet movement represents the localization of dynamic outflow obstruction in hypertrophic obstructive cardiomyopathy.