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

Interventions in Hypertrophic Obstructive Cardiomyopathy

Obstructive hypertrophic cardiomyopathy is the most common genetically transmitted cardiomyopathy that is associated with significant morbidity and mortality. Despite contemporary treatments and interventions, the management of patients with obstructive hypertrophic cardiomyopathy remains poorly defined compared with other branches of cardiology. In this review, we discuss established and novel therapeutic interventions in patients with obstructive hypertrophic cardiomyopathy with a focus on percutaneous and surgical strategies including surgical myectomy, mitral valve repair or replacement, percutaneous alcohol septal ablation, pacemaker and cardioverter-defibrillator implantation, septal embolization, radiofrequency endocardial catheter ablation, and percutaneous intramyocardial septal radiofrequency ablation.

Prognostic Implication of Mitral Valve Disease and Its Progression in East Asian Patients With Hypertrophic Cardiomyopathy

Background Hypertrophic cardiomyopathy (HCM) is a genetic disorder affecting not only the myocardium but also the mitral valve (MV) and its apparatus. This study aimed to investigate the prognostic implication of MV disease and its progression in East Asian patients with HCM. Methods and Results We assessed MV structure and function on the indexed echocardiogram of 1185 patients with HCM (mean±SD age, 60±14 years; men, 67%) in a longitudinal HCM registry, and 667 patients who performed follow-up echocardiogram after 3 to 5 years were also analyzed. Progression of mitral regurgitation (MR) was defined as the increase of at least 1 grade. Clinical outcomes were defined as a composite of cardiovascular death, heart failure hospitalization, MV surgery or septal myectomy, and heart transplantation. Most of the entire cohort was nonobstructive type (n=1081 [91.2%]). A total of 278 patients (23.5%) showed at least mild MR on indexed echocardiogram. MR, systolic anterior motion, and mitral annular calcification were more prevalent in patients with obstructive HCM. During 7.0±4.0 years of follow-up, presence of MR was independently associated with poor clinical outcomes (hazard ratio [HR], 1.60 [95% CI, 1.07-2.40]; P=0.023). On follow-up echocardiogram, 67 (10.0%) patients showed MR progression, and it was independently associated with poor prognosis (HR, 2.46 [95% CI, 1.29-4.71]; P=0.007). Conclusions In East Asian patients with HCM whose major type is nonobstructive, MV disease is common. MR, systolic anterior motion, and mitral annular calcification are more prevalent in patients with obstructive HCM. The presence and progression of MR are associated with a poor prognosis in patients with HCM.

Transapical Ventricular Remodeling for Hypertrophic Cardiomyopathy With Systolic Cavity Obliteration

BACKGROUND

Some patients with hypertrophic cardiomyopathy (HCM) present with reduced left ventricular (LV) stroke volume and elongated systolic cavity obliteration due to symmetric LV hypertrophy. In this report, we detail our experience with transapical septal myectomy to enlarge the LV volume and to relieve cavity obliteration in this unique subgroup of patients with HCM.

METHODS

We analyzed 38 patients with HCM who had extended symmetric LV hypertrophy and underwent transapical septal myectomy to enlarge the LV cavity from February 2001 to May 2021.

RESULTS

At the time of evaluation for operation, 84.2% (n = 32) of the patients were in New York Heart Association class III/IV. The peak oxygen consumption was 51.5% (44.0%-58.0%) of the normal predicted values on the preoperative exercise stress test (n = 16). Preoperative left atrial sizes in this cohort were enlarged (left atrial volume index, 39.0 [33.5-51.5] mL/m²), despite only 4 patients with moderate or greater mitral valve regurgitation. All patients underwent transapical septal myectomy to enlarge the LV cavity size. There was no postoperative (within 30 days) death. During a median (interquartile range) follow-up of 3.4 (0.7-6.9) years, the estimated survival rates were 100%, 92%, and 87% at 1, 3, and 5 years, respectively. Follow-up surveys suggested that 16 of the 17 contacted patients experienced improvement in their heart function after the procedure.

CONCLUSIONS

Transapical myectomy to enlarge LV cavity volume can be performed safely with good early survival and functional results. This procedure is an important alternative to cardiac transplantation for HCM patients with systolic cavity obliteration and progressive heart failure.

Intrinsic mitral valve alterations in hypertrophic cardiomyopathy sarcomere mutation carriers

Aims

Mitral valve (MV) abnormalities are recognized features of hypertrophic cardiomyopathy (HCM), and there is preliminary evidence suggesting they are intrinsic phenotypic manifestations of sarcomere mutations, present in mutation carriers without left ventricular (LV) hypertrophy (subclinical HCM). However, further study is required to characterize the nature of these changes and their functional impact. Thus, we performed comprehensive echocardiographic analysis of MV structure and function on a genotyped population.

Methods and results

MV and papillary muscle echocardiographic parameters were measured in 192 genotyped individuals, including 50 overt HCM, 79 subclinical HCM, and 63 mutation-negative, healthy relatives as normal controls. Compared to controls, subclinical HCM subjects had elongated anterior MV leaflets relative to LV end-diastolic volume index (0.57 ± 0.02 vs. 0.51 ± 0.02 mm/mL/m2, P = 0.013) and anteriorly displaced papillary muscles [decreased papillary-septal separation (31.1 ± 0.7 vs. 34.2 ± 0.9 mm, P = 0.004) and relative antero-posterior position ratio of the papillary muscles (0.67 ± 0.01 vs. 0.71 ± 0.01, P = 0.011]. Similar findings were identified comparing overt HCM to controls. These MV changes were associated with an increased prevalence of systolic anterior motion (SAM) of the MV amongst subclinical HCM subjects.

Conclusions

Sarcomere mutations are associated with primary abnormalities of the MV apparatus, specifically excess anterior leaflet length relative to LV cavity size and anterior displacement of the papillary muscles; both features predisposing to SAM. These abnormalities appear to be early phenotypic consequences of sarcomere mutations, observed in mutation carriers with normal LV wall thickness.

Hypertrophic Cardiomyopathy-Past, Present and Future

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy with a prevalence of 1 in 500 in the general population. Since the first pathological case series at post mortem in 1957, we have come a long way in its understanding, diagnosis and management. Here, we will describe the history of our understanding of HCM including the initial disease findings, diagnostic methods and treatment options. We will review the current guidelines for the diagnosis and management of HCM, current gaps in the evidence base and discuss the new and promising developments in this field.

The Remarkable 50 Years of Imaging in HCM and How it Has Changed Diagnosis and Management: From M-Mode Echocardiography to CMR

The almost 50-year odyssey of cardiac imaging in hypertrophic cardiomyopathy (HCM), revisited and described here, has been remarkable, particularly when viewed in the timeline of advances that occurred during a single generation of investigators. At each step along the way, from M-mode to 2-dimensional echocardiography to Doppler imaging, and finally over the last 10 years with the emergence of high-resolution tomographic cardiac magnetic resonance (CMR), evolution of the images generated by each new technology constituted a paradigm change over what was previously available. Together, these advances have transformed the noninvasive diagnosis and management of HCM in a number of important clinical respects. These changes include a more complete definition of the phenotype, resulting in more reliable clinical identification of patients and family members, defining mechanisms (and magnitude) of left ventricular outflow obstruction, and novel myocardial tissue characterization (including in vivo detection of fibrosis/scarring); notably, these advances afford more precise recognition of at-risk patients who are potential candidates for life-saving primary prevention defibrillator therapy. This evolution in imaging as applied to HCM has indelibly changed cardiovascular practice for this morphologically and clinically complex genetic disease.

Surgical treatment for hypertrophic cardiomyopathy: a historical perspective

Our understanding of hypertrophic cardiomyopathy (HCM) as a disease entity has increased dramatically over the last half century. There has been a concerted effort by several surgical groups to develop operative techniques to relieve left ventricular outflow tract (LVOT) obstruction and alleviate symptoms. This paper traces the development of transaortic septal myectomy, the current gold standard therapy for relief of LVOT obstruction, in symptomatic patients refractory to medical treatment. In addition, we introduce newer methods for myectomy that have expanded the role of surgery in patients with various forms of HCM.

The 50-year history, controversy, and clinical implications of left ventricular outflow tract obstruction in hypertrophic cardiomyopathy from idiopathic hypertrophic subaortic stenosis to hypertrophic cardiomyopathy: from idiopathic hypertrophic subaortic stenosis to hypertrophic cardiomyopathy

Dynamic obstruction to left ventricular (LV) outflow was recognized from the earliest (50 years ago) clinical descriptions of hypertrophic cardiomyopathy (HCM) and has proved to be a complex phenomenon unique in many respects, as well as arguably the most visible and well-known pathophysiologic component of this heterogeneous disease. Over the past 5 decades, the clinical significance attributable to dynamic LV outflow tract gradients in HCM has triggered a periodic and instructive debate. Nevertheless, only recently has evidence emerged from observational analyses in large patient cohorts that unequivocally supports subaortic pressure gradients (and obstruction) both as true impedance to LV outflow and independent determinants of disabling exertional symptoms and cardiovascular mortality. Furthermore, abolition of subaortic gradients by surgical myectomy (or percutaneous alcohol septal ablation) results in profound and consistent symptomatic benefit and restoration of quality of life, with myectomy providing a long-term survival similar to that observed in the general population. These findings resolve the long-festering controversy over the existence of obstruction in HCM and whether outflow gradients are clinically important elements of this complex disease. These data also underscore the important principle, particularly relevant to clinical practice, that heart failure due to LV outflow obstruction in HCM is mechanically reversible and amenable to invasive septal reduction therapy. Finally, the recent observation that the vast majority of patients with HCM have the propensity to develop outflow obstruction (either at rest or with exercise) underscores a return to the characterization of HCM in 1960 as a predominantly obstructive disease.

The value of changes in QRS width and in ST-T segment during exercise test in hypertrophic cardiomyopathy for identification of associated coronary artery disease

OBJECTIVES

Non-invasive methods cannot reliably predict the presence of coronary artery disease (CAD) in hypertrophic cardiomyopathy (HCM). This study aims to define the accuracy of QRS width changes versus standard ST-T criteria for recognition of associated ischemic CAD in patients with HCM undergoing exercise testing (ET).

METHODS

A retrospective study including patients with HCM. HCM was defined by left ventricular hypertrophy (LVH) of unknown etiology of at least 15 mm. Coronary angiography was performed as a gold standard for definition of CAD (> or =70% obstruction in at least one major artery). QRS width duration was measured at peak ET by a computerized method employing an optical scanner. No changes in QRS width or shortening during ET were considered normal; QRS width prolongation of more than 3 ms was defined as abnormal.

RESULTS

68 patients (56/12 M/F) aged 60+/-12 y were studied. During ET, abnormal QRS response was found in 40 (58.8%) and Ischemic ST-T changes in 52 (76.5%) patients. CAD in at least one artery was diagnosed in 31 patients (45.5%). The sensitivity of QRS width versus ST-T changes during ET for associated CAD was 82% and 28%, respectively. Specificity was 75% and 48%, respectively. Positive and negative predictive values were 88%; 68% for QRS width and 67%; 59% for ST-T changes respectively.

CONCLUSIONS

In patients with HCM undergoing ET, the association with CAD was more accurately predicted by an increase in QRS complex width than by standard criteria of ST-T segment changes. Thus, its use should be encouraged, especially in patients with HCM.

Transesophageal echocardiographic evaluation of mitral regurgitation in hypertrophic cardiomyopathy: contributions of eccentric left ventricular hypertrophy and related abnormalities of the mitral complex

This study was designed to evaluate the contribution of eccentric left ventricular hypertrophy and its related organic and spatial abnormalities of the mitral complex to the occurrence of mitral regurgitation in patients with hypertrophic cardiomyopathy We selected 45 consecutive patients with systolic mitral regurgitation by color Doppler echocardiography and performed transesophageal echocardiography in all patients. Eighteen patients were in the obstructive group and 27 patients were in the nonobstructive group of hypertrophic cardiomyopathy with asymmetric septal hypertrophy. Twenty subjects without any cardiac disorders served as the control group. The maximum area of mitral regurgitation was significantly greater in the obstructive group than in the nonobstructive group. Mitral regurgitation appeared more frequently during pansystole in the two groups with hypertrophic cardiomyopathy, particularly in the obstructive group. Mitral valve prolapse was observed in 20 (44%) of the 45 patients with hypertrophic cardiomyopathy. Distances between the posterior papillary muscle and anterior or posterior mitral anulus were significantly smaller in the two groups with hypertrophic cardiomyopathy than in the normal control group. In the obstructive group, the length of the anterior mitral leaflet and the thickness of the rough zone of the anterior mitral leaflet at mid-diastole were significantly greater than in the other groups. Systolic anterior motion was observed in all patients with obstructive cardiomyopathy and contact between the interventricular septum and the anterior mitral leaflet during early diastole was observed in 17 of the 18 patients in the obstructive group.(ABSTRACT TRUNCATED AT 250 WORDS)

Diversity of structural mitral valve alterations in hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is characterized by an asymmetrically hypertrophied left ventricle and is regarded as a disease of cardiac muscle.

METHODS AND RESULTS

To assess the possibility that the mitral valve itself may be involved in the disease process, we studied mitral valves from 94 patients with HCM and 45 normal control subjects. The area of the mitral leaflets was increased in patients with HCM compared with control subjects (12.9 +/- 3.7 versus 8.7 +/- 2.0 cm2; p less than 0.001). For the overall group of patients, this increase was largely caused by an increase in anterior leaflet length (2.2 +/- 0.5 cm for HCM versus 1.8 +/- 0.3 cm for control subjects; p less than 0.001), because circumference did not differ between the two groups. Mitral leaflet area was increased (greater than or equal to 12.0 cm2) in 55 (58%) of the 94 valves. In 12 of these 55 valves, both the anterior and posterior leaflets were enlarged; the other 43 valves had asymmetrical or segmental enlargement of either the anterior leaflet (36 patients) or a portion of posterior leaflet (seven patients). In addition, nine patients had a congenital malformation of the mitral apparatus in which one or both papillary muscles inserted directly into anterior mitral leaflet (mitral valve area was normal in seven of the nine).

CONCLUSIONS

Sixty-two (66%) of 94 mitral valves had a constellation of structural malformations, including increased leaflet area and elongation of the leaflets or anomalous papillary muscle insertion directly into anterior mitral leaflet. These findings expand the morphological definition of HCM by demonstrating that the disease process is not confined to cardiac muscle but rather many patients also have structural abnormalities of the mitral valve that are unlikely to be acquired or secondary to mechanical factors.

Hypertrophic cardiomyopathy: long-term effects of propranolol versus verapamil in preventing sudden death in "low-risk" patients

The aim of this study was to evaluate retrospectively the outcome of 101 patients who were assigned to long-term therapy with propranolol (55 patients) or verapamil (46 patients) between 1980 and 1988. Baseline clinical, electrocardiographic, and echocardiographic data were similar in both groups. Exclusion criteria were the evidence of complex ventricular arrhythmias, a family history of the disease and/or sudden death, previous syncopal episodes, or left ventricular dysfunction. During a mean follow-up of 4 +/- 3 years (range: 1-9 years), side effects were more commonly recorded in patients who were treated with verapamil rather than in propranolol-treated patients (8 vs. 3, respectively), though the difference was not statistically significant. Sixteen patients (13 propranolol-treated patients and three verapamil-treated ones, p less than 0.05) died suddenly while on treatment. In addition, three patients who stopped verapamil because of adverse reactions died from heart failure after withdrawal, but before the end of the follow-up period. The assessment of total mortality on the intention-to-treat basis showed that death due to cardiac causes occurred in 13 propranolol-treated patients and in six verapamil-treated patients (ns). Thus, verapamil was more effective than propranolol in preventing sudden death during long-term therapy of "low-risk" patients with hypertrophic cardiomyopathy, though its administration was associated with the occurrence of non-sudden cardiac deaths and a high incidence of side effects.

Electrocardiographic findings in patients with hypertrophic cardiomyopathy. Relation to presenting features and prognosis

The relation of ECG findings to presenting features and prognosis was evaluated in 125 consecutive patients with hypertrophic cardiomyopathy (HC). Seventy-nine men and 46 women (mean age, 34 +/- 7 years) were studied since 1970. Most ECG features were similar in patients with and without a left ventricular outflow tract gradient. Those with obstruction had a higher prevalence of left ventricular hypertrophy according to ECG voltage criteria (54% vs. 28%, p less than 0.01), whereas higher grade ventricular arrhythmias were more common in patients without an outflow gradient (20% vs. 7%, p less than 0.05). The prevalence of ECG abnormalities was also similar in younger (less than or equal to 14 years) and older patients (greater than 14 years), and only repolarization abnormalities were more frequently detected in the older age group (56% vs. 32%, p less than 0.025). Stratification of patients according to the clinical state revealed that those who had moderate to severe functional limitation had a higher prevalence of atrial fibrillation than asymptomatic or mildly symptomatic patients (24% vs. 1%, p less than 0.001). There were no significant differences in most hemodynamic variables among patients dichotomized according to any specific ECG abnormality. Only patients with atrial fibrillation had significantly higher right ventricular end-diastolic pressure (10 +/- 7 vs. 6 +/- 4 mmHg, p less than 0.01), lower systolic index (22 +/- 8 vs. 37 +/- 15 ml/m2; beat, p less than 0.02) and lower ejection fraction (53 +/- 8 vs. 64 +/- 10%, p less than 0.001) than those in sinus rhythm.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term prognosis in children with hypertrophic cardiomyopathy: an analysis of 37 patients aged less than or equal to 14 years at diagnosis

The relation of clinical, electrocardiographic, and hemodynamic findings at diagnosis to presenting features and prognosis of hypertrophic cardiomyopathy in childhood was evaluated in 37 consecutive patients below 14 years of age at time of diagnosis (24 males and 13 females, mean age 7 +/- 4 years). A left ventricular out-flow tract gradient (mean 42 +/- 27 mmHg) was detected at cardiac catheterization in 13 (35%) patients. Clinical, electrocardiographic, and hemodynamic features in patients with and without a pressure gradient were similar. Patients who had moderate to severe functional limitation had a higher incidence of syncopal episodes (p less than 0.001), lower ejection fraction (p less than 0.01), raised pulmonary artery pressure (p less than 0.001), and left ventricular end-diastolic pressure (p less than 0.01). During a follow-up of 9.2 +/- 5.1 years (range 2-18), 9 (24%) patients died suddenly (2 with a recorded left ventricular outflow tract gradient). Univariate analysis showed that reduced ejection fraction (p = 0.0001), syncopal episodes (p = 0.003), increased left ventricular end-diastolic pressure (p = 0.03), and severe dyspnea (p = 0.04) were associated with a poor prognosis. However, multivariate analysis revealed ejection fraction (p = 0.0001) and syncopal episodes (p = 0.0097) as independent predictors of survival. In conclusion, sudden cardiac death was common and was well predicted by the combination of left ventricular dysfunction and syncope at time of diagnosis.

Chordal geometry determines the shape and extent of systolic anterior mitral motion: in vitro studies

In patients with hypertrophic cardiomyopathy, the mitral valve moves anteriorly and assumes a unique shape, with mitral-septal contact centrally and preserved valve orifice area laterally. This shape is not clearly predicted by the Venturi mechanism, which stresses flow above the valve as opposed to changes intrinsic to the valve. On the other hand, it has been suggested that displacement of the papillary muscles anteriorly and toward one another, as observed in this disease, can promote anterior mitral valve motion and produce this unusual shape. The purpose of this in vitro study was to test the hypotheses that anterior motion of a membrane in a flow field can be generated by altering the distribution or effectiveness of chordal tension tethering the membrane, and that the shape achieved by this membrane depends on the geometry of chordal tension. Accordingly, a horizontal leaflet mounted in a flow chamber was attached by chords at its distal end to a series of upstream screws. Chordal tension could be varied by turning the screws or redirected by shifting the screws anteriorly. Anterior leaflet motion having the same unusual configuration seen in patients was reproduced by decreasing central chordal restraint while tension on the leaflet edges was maintained. Directing chordal tension anteriorly caused greater degrees of anterior motion at earlier stages in the release of chordal restraint; increased flow rate had a similar but less marked effect. These studies suggest that primary geometric alterations in the papillary-mitral apparatus can play an important role in determining the presence and geometry of systolic anterior mitral motion. The nature of these alterations suggests a role for anterior and inward papillary muscle displacement in promoting such motion. The geometric factors embodied in this model can explain many observed features of this motion not adequately explained by the Venturi effect, such as early systolic onset and the importance of a distal residual leaflet. Finally, flow visualization studies emphasize the importance in this process of drag forces caused by interposing the leaflet into the flow stream, and of geometric factors that enhance such forces.

Relationship between mitral regurgitation and left ventricular outflow obstruction in hypertrophic cardiomyopathy

To clarify the relationship between mitral regurgitation and left ventricular outflow obstruction, Doppler and two-dimensional echocardiographic studies were performed in 62 patients with hypertrophic cardiomyopathy (22 with and 40 without obstruction caused by mitral systolic anterior motion with septal contact). Pulsed Doppler echocardiography with color Doppler flow imaging demostrated that in 20 of the 22 patients with obstruction, mitral regurgitation occurred mainly during midsystole from the onset to the end of mitral-septal contact. Such midsystolic mitral regurgitation was not observed in patients without obstruction, except in three of 25 patients with mild mitral systolic anterior motion without septal contact. Furthermore, that regurgitation developed or disappeared together with the obstruction during follow-up periods or pharmacologic interventions. Two-dimensional echocardiography showed that in 21 of the 22 patients with obstruction, a distal residual portion of the "anterior" mitral leaflet moved anteriorly in early systole and protruded into the outflow tract during midsystole to cause the obstruction. In the other patient with obstruction, who had only early systolic mitral regurgitation, a distal residual "posterior" leaflet moved similary. These results may indicate that the midsystolic mitral regurgitation is hydrodynamically induced by the midsystolic pressure gradient across the protruding distal residual anterior mitral leaflet.

An integrated mechanism for systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy based on echocardiographic observations

Although many mechanisms have been proposed to explain systolic anterior motion (SAM) of the mitral valve in hypertrophic cardiomyopathy, the precise mechanism of its onset and cessation remain undefined. The Venturi theory, based on increased flow velocity in a narrowed outflow tract, is widely accepted but fails to explain several important characteristics of SAM. It also neglects the potential role of drag forces generated by interposition of the leaflets into the path of ejection and of factors that would decrease the effectiveness of papillary muscle restraint. In order to obtain further insight into the mechanism of SAM, a detailed geometric study of the left ventricle and mitral apparatus was performed with cross-sectional echocardiography in three equal-sized groups of patients with hypertrophic cardiomyopathy and SAM, patients with hypertrophy and no anterior motion, and normal control subjects. A salient finding was that SAM began prior to ejection in patients with hypertrophic cardiomyopathy, which cannot be explained by the Venturi theory. Further, SAM began and was most prominent in the central portion of the leaflet as opposed to its lateral edges; this finding is not predicted by the Venturi mechanism. In addition to outflow tract narrowing, other structural changes unique to patients with SAM included anterior and inward displacement of the papillary muscles, anterior displacement of the mitral leaflets, and elongation of the mitral leaflets, which were, on the average, 1.5 to 1.7 cm longer than in the other subjects (p less than 0.0001). On the basis of these observations, an integrated mechanism for the initiation and resolution of SAM is proposed that would explain observed features such as onset before ejection and central prominence. This mechanism combines the effects of outflow tract narrowing with those of papillary muscle displacement. In particular, anterior and inward displacement of the papillary muscles can be predicted to alter the effectiveness of chordal support so that the central leaflet portions become relatively slack and are more readily displaced anteriorly. The altered distribution of chordal tension can also be predicted to orient the distal leaflets upward into the outflow tract at the onset of systole, prior to aortic valve opening, so that ventricular ejection will actually drag the interposed leaflets anteriorly. The resolution of SAM can be understood in terms of a reverse Venturi effect created by mitral regurgitation, as well as continued traction of the centrally displaced papillary muscles on the lateral leaflet margins.(ABSTRACT TRUNCATED AT 400 WORDS)

Angiographic and hemodynamic correlations in hypertrophic cardiomyopathy with intracavitary systolic pressure gradients

To correlate angiographic and hemodynamic events in hypertrophic cardiomyopathy (HC), 14 patients with HC were investigated using pressure recordings and caudocranial left anterior oblique contrast angiography. Patients were separated into 2 groups on the basis of the presence (group I) or absence (group II) of systolic anterior motion of the anterior mitral leaflet on caudocranial angiography. In group I (10 patients), the pressure gradient could be recorded with the left ventricular (LV) catheter in the nonobliterated inflow region of the left ventricle. Simultaneous micromanometer tracings and caudocranial angiography revealed that contact between the anterior mitral leaflet and the ventricular septum was an early systolic event (occurring 136 +/- 33 ms after the R wave of the electrocardiogram) and was coincident with the onset of the pressure gradient. Cavitary obliteration was present in only 7 of 10 patients in group I, and occurred late in systole well after the peak gradient (292 +/- 28 ms after the R wave). In group II (4 patients), the pressure gradients could be recorded only from the obliterated portion of the ventricle distal to the level of the papillary muscles. Total LV cavitary obliteration was present in all group II patients. In 1 patient, simultaneous micromanometer pressure recording and caudocranial angiography revealed that cavitary obliteration preceded the peak gradient by 40 ms. Thus, in group I patients the onset of the pressure gradient is coincident with mitral leaflet-septal contact, while cavitary obliteration is an inconsistent late systolic event.(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns and timing of Doppler-detected intracavitary and aortic flow in hypertrophic cardiomyopathy

This study describes the velocity characteristics of left ventricular and aortic outflow in 25 patients with hypertrophic "obstructive" cardiomyopathy. Systematic pulsed and continuous wave Doppler analysis combined with phonocardiography and M-mode echocardiography was used to establish the pattern and timing of outflow in the basal and provoked states. This analysis suggests that 1) the high velocity left ventricular outflow jet can be reliably discriminated from both aortic flow and the jet of mitral regurgitation using Doppler ultrasound; 2) the Doppler velocity contour responds in a characteristic fashion to provocative influences including extrasystole and Valsalva maneuver; 3) the onset of mitral regurgitation occurs well before detectable systolic anterior motion of the mitral valve; 4) left ventricular flow velocities are elevated at the onset of systolic anterior motion of the mitral valve, suggesting a significant contribution of the Venturi effect in displacing the leaflets and chordae; 5) the high velocities of the outflow jets are largely dissipated by the time flow reaches the aortic valve; and 6) late systolic flow in the ascending aorta is nonuniform, with formation of distinct eddies that may contribute to "preclosure" of the aortic valve.

Human lymphocyte antigens in hypertrophic cardiomyopathy

An increasing number of genetic studies in hypertrophic cardiomyopathy challenge conventional views on inheritance and suggest genetic heterogeneity or non-genetic disease. We have found changes in relative risk for some antigens with significantly increased frequency of HLA antigen DR4 in this condition. These findings are consistent with there being a genetic component in susceptibility to hypertrophic cardiomyopathy. No evidence was found for HLA linkage using either sib pair analysis or lod scores. This suggests that hypertrophic cardiomyopathy does not have a disease susceptibility gene related to the HLA region on the short arm of chromosome number six. Population HLA associations with hypertrophic cardiomyopathy must thus be explained by other influences of the genetic background on disease susceptibility.

Evaluation of hypertrophic cardiomyopathy by Doppler color flow imaging: initial observations

We evaluated hypertrophic cardiomyopathy in 12 patients by Doppler color flow imaging and continuous-wave Doppler echocardiography. Mitral regurgitation was detected by continuous-wave Doppler echocardiography in eight patients and was related to the degree of systolic anterior motion of the mitral valve. Adequate color flow images were obtained in 10 of the 12 patients, and mitral regurgitation was demonstrated in 6. A qualitative and quantitative analysis of the color flow imaging revealed a temporal pattern in the left ventricular outflow tract that consisted of normal-velocity laminar flow during early systole followed by turbulent flow in midsystole. The maximal amount of mitral regurgitation on color flow imaging occurred late in systole, after the appearance of turbulent flow in the left ventricular outflow tract. Of the 12 patients, 10 had late-peaking continuous-wave Doppler velocity profiles in the left ventricular outflow tract. The peak velocity detected in the left ventricular outflow tract was positively correlated with the degree of systolic anterior motion of the mitral valve. Patients with higher peak velocities in the left ventricular outflow tract had prolonged ejection times. These findings on Doppler echocardiography support the concept of left ventricular outflow obstruction in some patients with hypertrophic cardiomyopathy.

Obstruction is unimportant in the pathophysiology of hypertrophic cardiomyopathy

There has been a longstanding controversy about the significance of intracavitary pressure gradients in hypertrophic cardiomyopathy (HCM). It has been generally assumed that the gradient is the result of an 'obstruction' that impedes left ventricular outflow and which can be relieved by operative intervention. In the first decade after the discovery of HCM (1957-66), the site of 'obstruction' was thought to be a muscular sphincter or contraction ring in the submitral region of the left ventricle, and operations designed to emulate pyloromyectomy (for hypertrophic pyloric stenosis) were developed. Following a challenge to the existence of the 'contraction ring' and an alternative non-obstructive explanation of the pressure gradient, the site of 'obstruction' was translocated to a point of apposition between the anterior mitral leaflet and the interventricular septum, a result of systolic anterior motion (SAM) of the mitral valve. Despite the translocation of the site and mechanism of 'obstruction', the operation for 'relief of obstruction' has not changed significantly. The newer site of 'obstruction' has been challenged on the grounds that the ventricle is not demonstrably impeded in its emptying; when a gradient is provoked, the ventricle empties more rapidly and more completely than it does without a gradient. In addition to a non-obstructive explanation of the gradient, other phenomena thought to be indicative of 'obstruction' can be explained by rapid and complete emptying of the ventricle (cavitary obliteration). Since the morbidity and mortality of symptomatic HCM patients without pressure gradients may exceed that of patients with pressure gradients, it is suggested that 'obstruction' may be unimportant in the pathophysiology of HCM and attention should be focused on abnormal diastolic function and life threatening arrhythmias.

Left ventricular filling in hypertrophic cardiomyopathy: a pulsed Doppler echocardiographic study

Abnormal left ventricular diastolic properties have been described in patients with hypertrophic cardiomyopathy. To evaluate the diastolic filling characteristics of the left ventricle in patients with this disease, pulsed Doppler echocardiography was used to study mitral flow velocity in 17 patients with hypertrophic cardiomyopathy (11 with and 6 without systolic anterior motion of the mitral valve) and 16 age-matched normal subjects. There were no statistically significant differences between patients with hypertrophic cardiomyopathy with and without systolic anterior motion with regard to ventricular septal thickness, left ventricular posterior wall thickness, left ventricular internal dimensions or the extent of hypertrophy evaluated by two-dimensional echocardiography. Mitral regurgitation was detected by Doppler echocardiography in all 11 patients with and in 2 (33%) of the 6 patients without systolic anterior motion of the mitral valve. Early and late diastolic peak flow velocity, the ratio of late to early diastolic peak flow velocity and deceleration of early diastolic flow were measured from Doppler mitral flow velocity recordings. There were no statistically significant differences in these four indexes between the patients with systolic anterior motion and normal subjects. In contrast, the patients with hypertrophic cardiomyopathy without systolic anterior motion showed lower early diastolic peak flow velocity, higher ratio of late to early diastolic peak flow velocity and lower deceleration of early diastolic flow compared with the patients with systolic anterior motion and normal subjects, suggesting impaired left ventricular diastolic filling.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypertrophic cardiomyopathy. The importance of the site and the extent of hypertrophy. A review

Hypertrophic cardiomyopathy is a diverse clinical and pathophysiologic entity that involves principally the left ventricle and is caused by asymmetric or concentric hypertrophy of unknown cause. If asymmetric, the hypertrophy is usually greatest in the ventricular septum, but variations occur in which the hypertrophy may be maximal at the apex, at the midventricular level, or, rarely, in the free wall of the left ventricle. Right ventricular involvement is usually less evident. The principal abnormality in systole is the obstruction to left ventricular outflow caused by upper septal hypertrophy narrowing the outflow tract and setting the stage for Venturi forces to cause systolic anterior motion of the anterior or posterior mitral leaflets. The time of onset and duration of mitral leaflet-septal contact determine the magnitude of the pressure gradient. Mitral regurgitation invariably accompanies the obstruction to outflow. Ventriculomyotomy-myectomy surgery, by thinning the septum and widening the outflow tract, abolishes the abnormal mitral leaflet motion and, consequently, the obstruction to outflow and the mitral regurgitation. This form of surgery more dramatically relieves the systolic abnormalities and the accompanying symptoms than any form of medical therapy available today. The extent of hypertrophy is believed to be the principal determinant of the impaired left ventricular relaxation and increased chambers stiffness (decreased compliance) that characterize diastole in hypertrophic cardiomyopathy. Relaxation is impaired by the contraction load (the obstruction), by a decrease in the principal relaxation loads, by a pathologic degree of nonuniformity of contraction and relaxation, and in all likelihood, by impaired inactivation of the biochemical processes responsible for contraction (? due to primary or ischemia-induced calcium overload). Calcium channel-blocking agents may dramatically improve left ventricular relaxation by speeding up the inactivation process, by decreasing the degree of nonuniformity, or by altering the contraction and relaxation loads in a favorable manner. Atrial and ventricular arrhythmias are responsible for a significant proportion of the morbidity and mortality, and their occurrence also appears to depend on the extent of hypertrophy. Thus, the major manifestations of hypertrophic cardiomyopathy in systole and diastole as well as the disturbances of rhythm appear to be related to the site and/or extent of the hypertrophic process.(ABSTRACT TRUNCATED AT 400 WORDS)

Longitudinal changes in left ventricular diastolic function in hypertrophic cardiomyopathy

Digitised M-mode echocardiography was used to study the changes in left ventricular diastolic function over a 3-year period in 11 patients with hypertrophic cardiomyopathy an 14 normals. Compared to normal, in hypertrophic cardiomyopathy, isovolumic relaxation was prolonged (P less than 0.001) and mitral valve opening delayed relative to minimum dimension (P less than 0.001). There was a wide range of values for the peak rates of dimension increase and wall thinning, and although the means were normal, 6 and 8 patients respectively were outside the normal range. There were no significant mean changes in function during the 3.4 +/- 0.3 years of follow-up, but, in 3 patients, marked alterations in relaxation were observed. They showed a gross reduction in the delay in mitral valve opening (125 to 55 125 to 35 and 110 to 75 msec). There was little overall change in isovolumic relaxation in two, but in one patient it reduced from 95 to 50 msec. In most patients with hypertrophic cardiomyopathy, relaxation and diastolic function appear to remain stable over a period of 3 years, and none had an apparent deterioration. Some patients may have an apparently spontaneous "improvement" in function similar in extent to that described due to the therapeutic action of calcium antagonists.

Dynamic subaortic obstruction in hypertrophic cardiomyopathy: analysis by pulsed Doppler echocardiography

To determine whether true obstruction to left ventricular ejection exists in patients with hypertrophic cardiomyopathy and a subaortic gradient, pulsed Doppler echocardiography was used to analyze the patterns of left ventricular emptying in 50 patients with hypertrophic cardiomyopathy (20 with and 30 without evidence of obstruction) and in 20 normal subjects. In obstructive hypertrophic cardiomyopathy, left ventricular ejection was characterized by early and rapid emptying (76 +/- 14% of aortic flow velocity in the initial one-third of systole). The proportion of forward flow velocity occurring before initial mitral-septal contact (and hence, by inference before the onset of the subaortic gradient) was variable, but averaged 58%. In contrast, the proportion of forward flow velocity occurring after mitral-septal contact (and, therefore, concomitant with the gradient and increased intraventricular pressure) was considerable, averaging over 40%. Mid-systolic impedance to left ventricular outflow was suggested by the rapid deceleration in aortic flow velocity concomitant with mitral-septal contact and premature partial aortic valve closure. Furthermore, left ventricular ejection was prolonged (384 +/- 40 ms) and the ventricle continued to empty and shorten during the period when both the pressure gradient and markedly increased intraventricular pressures were present. In 16 of 20 patients, a relatively small second peak in flow velocity appeared in late systole. Since marked systolic anterior motion of the mitral valve was still present, the late systolic portion of forward flow velocity also appeared to be largely ejected during imposition of a mechanical impediment to outflow. In contrast, patients with nonobstructive hypertrophic cardiomyopathy showed no evidence of impedance to left ventricular ejection. Aortic flow velocity waveforms were similar to those of normal subjects, with flow persisting to aortic valve closure; significant mitral systolic anterior motion and partial mid-systolic aortic valve closure were absent, and the systolic ejection period was normal (303 +/- 27 ms).(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of ventricular emptying with and without a pressure gradient in patients with hypertrophic cardiomyopathy

Thirty three patients with hypertrophic cardiomyopathy were studied to determine whether the presence of an intraventricular pressure gradient impaired left ventricular emptying. Patients with resting gradients had a higher mean left ventricular ejection fraction (92 (6.4)%) than patients without a resting or inducible pressure gradient (75.5 (9)%). The rate and degree of emptying increased when gradients greater than 85 mm Hg were induced in two patients with insignificant mitral regurgitation. If the induced gradients had been the result of obstruction a decrease in the rate or degree of ventricular emptying would be expected. Higher ejection fractions in patients with intracavitary pressure gradients as well as enhanced rate and degree of left ventricular emptying with induced gradients are inconsistent with outflow obstruction. These findings support the concept that cavity obliteration is responsible for the pressure gradient in these patients with hypertrophic cardiomyopathy.

Relation between left ventricular gradient and relative stroke volume ejected in early and late systole in hypertrophic cardiomyopathy. Assessment with radionuclide cineangiography

Hypertrophic cardiomyopathy is characterised by hyperkinetic left ventricular function, but the effect of an outflow tract gradient on the haemodynamics of ejection remains controversial. To determine the functional importance of left ventricular gradients in hypertrophic cardiomyopathy technetium-99m gated equilibrium radionuclide angiography was performed in 18 normal subjects and 57 patients, 26 with and 31 without left ventricular gradients. Time activity curves were generated from list mode data, and the proportion of stroke volume ejected during various phases of systole was computed. The proportion of stroke volume ejected during the initial third, the initial 50%, and the initial 80% of systole was greater in patients with hypertrophic cardiomyopathy than in normal subjects but was identical in patients with and without left ventricular gradients. The duration of systole was similar in the three groups. These findings favour the interpretation that a left ventricular gradient does not represent true obstruction and are consistent with previous observations that clinical features and prognostic indicators do not relate to gradients in this disease.

An evaluation of two-dimensional echocardiography in the diagnosis of hypertrophic cardiomyopathy

Various anatomical and functional features of hypertrophic cardiomyopathy are analyzed in view of the data provided by two-dimensional echocardiography. Measurement of septal thickness is crucial, and is best done by a combination of M-Mode and 2-D echo. Two types of systolic anterior movement of the mitral valve (SAM) are observed and are related to the degree of subvalvular gradient. The specificity of these patterns of SAM is analyzed. The functional anatomy of the mitral valve in relation to the presence and degree of mitral regurgitation shows that although the presence and type of SAM are important, there are other causes of mitral regurgitation in hypertrophic cardiomyopathy unrelated to SAM. We emphasize the fact the 2-D echo cannot "diagnose" hypertrophic cardiomyopathy except when cardiac hypertrophy plus SAM involving the body of the mitral valve is seen; in the remaining cases, 2-D echo confirms/suggests the clinical diagnosis.

Morphologic determinants of hemodynamic state after ventricular septal myotomy-myectomy in patients with obstructive hypertrophic cardiomyopathy: M mode and two-dimensional echocardiographic assessment

To define the morphologic features of the left ventricle after ventricular septal myotomy-myectomy and to elucidate the structural changes associated with a postoperative reduction in the pressure gradient, 28 patients with obstructive hypertrophic cardiomyopathy were studied with M mode and qualitative and quantitative two-dimensional echocardiography. Nine patients with a marked reduction in the pressure gradient (no or small, less than or equal to 25 mm Hg, residual basal gradient) demonstrated a marked reduction in septal thickness after surgery (23 +/- 6 to 13 +/- 4 mm; p less than .01), a concomitant increase in septal to mitral valve distance (20 +/- 2 to 30 +/- 5 mm; p less than .005), and a loss or substantial decrease in the magnitude of systolic anterior motion of the mitral valve. Two-dimensional echocardiographic results demonstrated an increase of over 100% in the cross-sectional area of the left ventricular outflow tract at onset of systole (2.2 +/- 0.6 to 5.5 +/- 3 cm2; p less than .01). In six of the patients postoperative paradoxic septal motion appeared to contribute importantly to the increased size of the outflow tract during ventricular systole. In contrast, nine patients with little or no change in the pressure gradient (residual basal gradient greater than or equal to 40 mm Hg) demonstrated a less marked decrease in septal thickness and no significant change in septal to mitral valve distance or magnitude of mitral systolic anterior motion. Furthermore, the postoperative left ventricular outflow tract area was significantly smaller in patients with residual basal gradients (3.0 +/- 1 cm2) than that in patients with no residual gradient (5.5 +/- 3 cm2; p less than .05). Ten patients with only provocable subaortic gradients after operation showed postoperative left ventricular outflow tract dimensions intermediate between those in patients with either residual basal gradient or no residual gradient. On the basis of this echocardiographic assessment of septal myotomy-myectomy, we conclude that abolition or reduction of the subaortic gradient after operation in patients with obstructive hypertrophic cardiomyopathy is largely the consequence of surgical enlargement of the left ventricular outflow tract area.

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).

Hypertrophic cardiomyopathy: a common disease with a good prognosis. Five year experience of a district general hospital

The manifestations and workload in a district general hospital cardiac unit of 39 unselected cases of hypertrophic cardiomyopathy over a five year period are reported. The "typical" form with asymmetrical septal hypertrophy and a gradient was found in only one third of patients, serious ventricular arrhythmias were probably no more common than in the general population, and no deaths occurred during a relatively short follow up (mean 3.1 years). It is concluded that although hypertrophic cardiomyopathy occupies a not insignificant proportion of cardiac workload, unselected cases presenting to a district general hospital represent a relatively mild disease without a grave prognosis.

Distribution of left ventricular hypertrophy in hypertrophic cardiomyopathy: a two-dimensional echocardiographic study

The distribution of left ventricular hypertrophy was assessed by M-mode and two-dimensional echocardiography in 89 patients with hypertrophic cardiomyopathy. Myocardial thickness was measured in the septum and the free and posterior wall in both the proximal and distal left ventricle. All patients had at least one myocardial region that was hypertrophied. The predominant pattern of hypertrophy was defined as symmetric (31%), asymmetric septal (55%) and distal ventricular (14%). The spectrum of wall thickness measurements between patients with symmetric hypertrophy was wide (1.5 to 4.5 cm) and was not related to age. In patients with asymmetric septal hypertrophy, the distribution of hypertrophy conformed to previously described patterns; hypertrophy was localized to the anterior septum (14%) or the anterior and posterior septum (35%) or involved both the septum and the left ventricular free wall (51%). The patients with distal ventricular hypertrophy had marked papillary muscle thickening, and only 1 of 12 patients could be correctly diagnosed using M-mode echocardiography. The proportion of patients with symmetric and distal ventricular hypertrophy was greater than that reported when patients are selected on the basis of M-mode diagnostic criteria. This reflects the limitations of the M-mode technique in the assessment of left ventricular hypertrophy and suggests that the recognition and understanding of hypertrophic cardiomyopathy have been biased by patients with asymmetric septal hypertrophy who previously were most readily identified.

Systolic anterior motion of the posterior mitral leaflet: a previously unrecognized cause of dynamic subaortic obstruction in patients with hypertrophic cardiomyopathy

Dynamic obstruction to left ventricular outflow in patients with hypertrophic cardiomyopathy usually occurs when the anterior mitral leaflet moves forward in systole and approaches or contacts the ventricular septum. However, we have recently identified, by M mode and two-dimensional echocardiography, 21 patients with hypertrophic cardiomyopathy who had a unique pattern of mitral valve motion characterized by abnormal mitral valve coaptation and systolic anterior motion of the posterior mitral leaflet. This abnormality of mitral valve motion was most reliably identified with two-dimensional echocardiography in views of the left ventricle obtained from the apex. At end-diastole the anterior and posterior mitral leaflets did not appear to coapt at their distal free margins. Rather, at mitral valve closure, the anterior mitral leaflet contacted the basal portion of posterior mitral leaflet. Subsequently, during systole the "residual" distal portion of posterior mitral leaflet approached or contacted the ventricular septum. Morphologic observations in nine other patients with hypertrophic cardiomyopathy suggested that systolic anterior motion of the posterior mitral leaflet is due to elongation of the middle scallop of the posterior leaflet, which probably comes into apposition with the ventricular septum during systole by passing through the space created by the normal pattern of chordal attachments onto the anterior mitral leaflet. Of the 16 patients who underwent cardiac catheterization, nine had basal subaortic gradients of 20 to 85 mm Hg, which were apparently due to moderate or marked systolic anterior motion of the posterior mitral leaflet. Ventricular septal myotomy-myectomies were performed in two patients and resulted in markedly diminished systolic anterior motion of the posterior mitral leaflet in each and abolition of subaortic gradient in the one patient who underwent postoperative cardiac catheterization. Hence, in patients with hypertrophic cardiomyopathy, systolic anterior motion of the posterior mitral leaflet (1) is not uncommon (identifiable in about 10% of a consecutively studied series of patients), (2) constitutes a previously undescribed mechanism for dynamic subaortic obstruction, and (3) is due to a malformation of the posterior mitral leaflet.

Significance of left ventricular outflow tract cross-sectional area in hypertrophic cardiomyopathy: a two-dimensional echocardiographic assessment

The morphologic determinants of subaortic obstruction in patients with hypertrophic cardiomyopathy are not completely understood. To define the relation between left ventricular outflow tract orifice size and presence or absence of subaortic obstruction, we studied 65 patients with hypertrophic cardiomyopathy and 16 normal controls by quantitative two-dimensional echocardiography. Left ventricular outflow tract area was measured at the onset of systole in the short-axis view in the stop-frame mode. Left ventricular outflow tract area was significantly smaller in patients with hypertrophic cardiomyopathy and subaortic obstruction (2.6 +/- 0.7 cm2) than in patients without obstruction (5.9 +/- 1.6 cm2, p less than 0.001). Twenty of 21 patients with obstruction had a left ventricular outflow tract area smaller than 4.0 cm2, whereas 28 of 30 patients without obstruction had a left ventricular outflow tract area of 4.0 cm2 or greater. The outflow tract area in patients with provocable obstruction (4.6 +/- 1.6 cm2) was intermediate between the areas of patients with and without obstruction. Left ventricular outflow tract area was significantly smaller in patients with hypertrophic cardiomyopathy (4.6 +/- 2.0 cm2) than in normal subjects (10.4 +/- 1.2 cm2, p less than 0.001). We conclude that the cross-sectional outflow tract area is closely related to the presence or absence of subaortic obstruction in patients with hypertrophic cardiomyopathy. Hence, the size of the outflow tract at the level of the mitral valve appears to be of major pathophysiologic significance in producing obstruction in these patients.

The natural history of left ventricular hypertrophy in hypertrophic cardiomyopathy: an electrocardiographic study

The natural history of electrocardiographic left ventricular hypertrophy was assessed in relation to clinical features, treatment with propranolol and prognosis in 100 patients with hypertrophic cardiomyopathy who were followed 5--20 years (mean 8 years). Seventy-one patients received propranolol, 120--800 mg/day (mean 240 mg). At diagnosis, the voltage measurement from SV1 + RV5 was 37 +/- 20 mm, the R wave in aVL was 12 +/- 6 mm and the mean frontal plane voltage was 15 +/- 10 mm. After 5 years, these values were increased to 43 +/- 22 mm (p less than 0.0002), 14 +/- 6 mm (p less than 0.003) and 17 +/- 10 mm (p less than 0.01), respectively. Neither a left ventricular outflow tract gradient nor propranolol treatment influenced these voltage changes. Twenty patients had an increase of more than 10 mm in SV1 + RV5, which was associated with exertional chest pain (p less than 0.006) and death (p less than 0.02). Four patients had a decrease of more than 10 mm in SV1 + RV5. Two of these received high-dose propranolol, one 720 mg/day for 12 years and another 800 mg/day for 12 years. No other patient received more than 480 mg of propranolol daily. In hypertrophic cardiomyopathy there is electrocardiographic evidence of progressive hypertrophy, which is associated with poor prognosis and is not influenced by treatment with propranolol in moderate dosage. Regression of hypertrophy is rare and may be related to long-term treatment with high-dose propranolol.

False diagnosis of subpulmonary obstruction by echocardiography in d-transposition of the great arteries

Twenty-one consecutive children (aged 3 to 14 months) with d-transposition of the great arteries were evaluated with standard M mode echocardiography at the time of hospital admission for routine preoperative cardiac catheterization. At catheterization, 6 of the 21 were found to have a systolic pressure gradient between the body of the left ventricle and the main pulmonary artery. Echocardiographic systolic anterior mitral valve motion was noted in nine patients, including five who did not have a left ventricular to pulmonary arterial systolic pressure gradient. Diastolic approximation of the anterior mitral leaflet to the septum was noted in 14 (9 without a gradient), pulmonary valve flutter was also present in 14 (9 without a gradient) and there was premature systolic pulmonary valve closure in 6 (3 without a gradient). Echographic left heart dimensions were not different in patients with a left ventricular outflow pressure gradient than in those without, but patients wit systolic anterior mitral valve motion and diastolic approximation of the mitral leaflet to the septum did have smaller left ventricular and pulmonary root dimensions than did those without these echocardiographic findings. Echocardiographic findings that have been described as suggesting left ventricular outflow obstruction in patients with d-transposition of the great arteries appear to be more related to size and configuration of the left ventricle than to the presence or absence of obstruction.

Postextrasystolic changes in systolic time intervals in the assessment of hypertrophic cardiomyopathy

To determine if postextrasystolic changes in systolic time intervals can be used to estimate the severity of resting or provocable left ventricular outflow pressure gradient, we studied the cardiac catheterisation records of 42 patients with hypertrophic cardiomyopathy looking for instances of a single premature beat preceded by a control sinus beat and followed by a postpremature sinus beat. There were 75 such instances in 25 patients. In comparison to the control beat, the pre-ejection period in the postpremature beat was shorter by deltaPEP = -20 +/- 11 ms in 73 of 75 instances, and remained unchanged in two. The ejection time in the postpremature beat was invariably longer by deltaET = 37 +/- 20 ms (range: 10 to 85 ms) and the pre-ejection period/ejection time ratio lower than control by delta(PEP/ET) = -0 . 10 +/- 0 . 05 (range: -0 . 01 to -0 . 25). Total electromechanical systole in the postpremature beat was shorter (11/75), the same (10/75), or longer (53/75) than in the control beat, the overall change being deltaEMS = -18 +/- 22 ms. Both deltaPEP and delta(PEP/ET) correlated poorly with the systolic peak left ventricular-aortic pressure gradient in either the control beat (Gc) or the postpremature beat (Gx), and also with the change in gradient (delta G) from the control to the postpremature beat. In contrast, significant linear correlations were found between delta EMS and either Gc, Gx, or delta G; and also between deltaET and either Gc, Gx, or deltaG. Since internal and external measurements of ejection time are known to be almost identical, the regression equation (deltaG = 1 . 65 delgaET -9) relating deltaET and deltaG should be useful for the non-invasive assessment of the magnitude of provocable left ventricular outflow pressure gradient in patients with hypertrophic cardiomyopathy with spontaneous or externally-induced premature beats.

Improved cineangiographic evaluation of hypertrophic cardiomyopathy by caudocranial left anterior oblique view

Seven patients with hypertrophic cardiomyopathy and one with discrete subaortic stenosis were studied with axial left ventriculography (caudocranial left anterior oblique view). In addition to the angiographic findings described on conventional views, the mitral valve, ventricular septum, and posterior left ventricular wall were better profiled than with conventional views and thus better evaluated. Systolic anterior motion of the anterior leaflet of the mitral valve was readily identifiable, which is usually not the case in nonangled views. From our experience, we strongly recommend that caudocranial left ventriculography be the procedure of choice in patients suspected of left ventricular outflow tract abnormalities and that biventricular angiography be abandoned for diagnostic purposes.