Hypertrophic cardiomyopathy.
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Cardiomyopathies↗
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[Study of the arrhythmogenicity of cardiomyopathies. Hypertrophic cardiomyopathies].
Forty-four cases of hypertrophic cardiomyopathy (23 men, 21 women; 55 +/- 15 years) referred for evaluation of chest pain (28 cases), dyspnoea (26 cases), palpitations (25 cases), dizziness (11 cases) and syncope (4 cases), were investigated prospectively between February 1983 and February 1989. The cardiomyopathy was concentric (N = 16), obstructive (N = 24) or apical (N = 4) and the diagnosis confirmed by angiography. Twenty-four hour Holter monitoring showed no ventricular extrasystoles in 43% of patients: the others had Grade I (25%), Grade III (2%), Grade 4A (14%) or 4B (16%) ventricular arrhythmias with diurnal predominance in half the cases. Patients with greater than or equal to Grade III ventricular extrasystoles had greater left axis deviation but did not differ from the others from the hemodynamic point of view. Exercise stress testing induced an isolated ventricular arrhythmia in 23% of patients and repetitive extrasystoles in 23%. The prevalence of surface late ventricular potentials was no greater in these patients than in normal subjects (4% vs 1%; NS). Programmed ventricular stimulation (N = 37) induced a repetitive response in only 25% of patients, with only two cases of sustained monomorphic ventricular tachycardia. There were no correlations between the results of programmed ventricular stimulation and those of Holter monitoring, exercise stress testing or late ventricular potential recording, but patients with inducible ventricular tachycardia or fibrillation had proportionally more syncopal episodes and greater than or equal to Grade III ventricular extrasystoles on Holter monitoring, but the difference was not statistically significant in this series.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Echocardiography, electrocardiography, and radiography of cats with dilatation cardiomyopathy, hypertrophic cardiomyopathy, and hyperthyroidism.
The echocardiographic, ECG, and radiographic findings of sequentially examined cats with dilatation cardiomyopathy (DCM, n = 7), hypertrophic cardiomyopathy (HCM, n = 8), and hyperthyroidism (HT, n = 20) were compared with those of healthy control cats (n = 11). Cats with DCM were easily differentiated from healthy cats by echocardiography and from cats with HCM and HT by a dilated left ventricle at end-diastole with a mean +/- SD of 2.20 +/- 0.36 cm, reduced fractional shortening (2.9% +/- 3.7%), reduced aortic amplitude (0.07 +/- 0.05 cm), reduced left ventricular wall amplitude (0.09 +/- 0.09 cm), and increased E-point septal separation (0.83 +/- 0.29 cm). The cats with HCM were most consistently recognized echocardiographically by increased left ventricular wall thickness at end-diastole (0.75 +/- 0.12 cm). Some cats with HT had abnormal echocardiograms with left ventricular wall hypertrophy. These cats could usually be differentiated from the cats with HCM because of normal or increased ventricular wall amplitude, aortic amplitude, or percentage of thickening of the left ventricular wall and interventricular septum. Left atrial enlargement (left atrial diameter greater than 1.57 cm or left atrium/aorta greater than 1.75) was commonly detected by the echocardiogram in cats with DCM, HCM, or HT. The echocardiogram was helpful in differentiating the type of cardiomyopathy (DCM, HCM, or HT) when plain thoracic radiographs indicated that cardiomegaly existed. The ECG may have indicated incorrectly that there was left ventricular enlargement in some cats with HT, and it did not indicate consistently that left ventricular enlargement existed when present in cats with DCM or HCM. The ECG was a poor indicator of left atrial enlargement in all cats.
Animals↗
Small coronary artery disease in cardiomyopathy: hypertrophic cardiomyopathy resembling dilated cardiomyopathy.
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Cardiomyopathy, Dilated↗
Hypertensive hypertrophic cardiomyopathy or hypertrophic cardiomyopathy with hypertension? A study of 78 patients.
Hypertensive hypertrophic cardiomyopathy may be a distinctive cardiac condition resulting from hypertension. Alternatively, this disease may represent the coincidence of a common disease, hypertension, with a relatively rare cardiomyopathy. A consecutive series of patients with hypertrophic cardiomyopathy and hypertension were studied and compared with age- and gender-matched patients with cardiomyopathy alone. Thirty-nine patients were identified as having hypertension; they ranged in age from 31 to 84 years (average 60 +/- 13); 82% were greater than 50 years old; 18 (46%) were women. When these patients were compared with the age-matched group with hypertrophic cardiomyopathy alone, there were no clinical or electrocardiographic differences between the two groups. By echocardiography, the hypertensive and nonhypertensive groups had a similar incidence of systolic anterior motion (77 versus 64%, respectively), mitral annular calcification (31 versus 31%), septal thickness greater than 20 mm (56 versus 46%) and outflow tract gradient greater than 20 mm (59 versus 67%). A posterior wall thickness greater than 13 mm was more frequent in the hypertensive group (54%) compared with the nonhypertensive group (31%) (p = 0.02). The findings show that hypertrophic cardiomyopathy with associated hypertension is a disease of the elderly. But, with the exception of thicker walls, the clinical and echocardiographic features of the patients with hypertension were indistinguishable from those of the age-matched and, hence, elderly group of patients with cardiomyopathy without hypertension. These findings suggest that hypertension may make hypertrophy worse, but that it is not the primary cause of the cardiomyopathy. Thus, the condition might be better termed "hypertrophic cardiomyopathy with hypertension."
Adult↗
[Hypertrophic cardiomyopathy. Arrhythmia in hypertrophic cardiomyopathy].
Hypertrophic cardiomyopathy is a relatively common genetic disorder with heterogeneity in mutations, forms of presentation, prognosis and treatment strategies. Hypertrophic cardiomyopathy is recognized as the most common cause of sudden cardiac death that occurs in young people, including athletes. The clinical diagnosis is complemented with the ecocardiographic study, in which an abnormal myocardial hypertrophy of the septum can be observed in the absence of a cardiac or systemic disease (arterial systemic hypertension, aortic stenosis). The annual sudden mortality rate is 1% and, in selected populations, it ranges between 3 and 6%. The therapeutic strategies depend on the different subsets of patients according to the morbidity and mortality, sudden cardiac death, obstructive symptoms, heart failure or atrial fibrillation and stroke. High risk patients for sudden death may effectively be treated with the automatic implantable cardioverter-defibrillator.
Adolescent↗
Noninvasive assessment of left ventricular diastolic function by pulsed Doppler echocardiography in patients with hypertrophic cardiomyopathy.
Hypertrophic cardiomyopathy is a primary myocardial disease in which symptoms may frequently result from impaired left ventricular relaxation, filling and compliance. In the present investigation, Doppler echocardiography was utilized to measure transmitral flow velocity and thereby assess left ventricular diastolic performance noninvasively in a group of 111 patients representative of the broad clinical spectrum of hypertrophic cardiomyopathy. In patients with hypertrophic cardiomyopathy, all Doppler indexes of diastolic relaxation and filling differed significantly (p less than 0.001) from those obtained in 86 control subjects without heart disease, namely, prolongation of isovolumic relaxation (94 +/- 24 versus 78 +/- 12 ms) and of the early diastolic peak of flow velocity (244 +/- 55 versus 220 +/- 28 ms), as well as slower deceleration (3.4 +/- 1.4 versus 4.9 +/- 1.3 m/s2) and reduced maximal flow velocity in early diastole (0.5 +/- 0.2 versus 0.6 +/- 0.1 m/s). As an apparent compensation for impaired relaxation and early diastolic filling, the atrial contribution to left ventricular filling was increased, as shown by increased late diastolic flow velocity (0.4 +/- 0.3 versus 0.3 +/- 0.1 m/s) and reduced ratio of maximal flow velocity in early diastole to that in late diastole (1.4 +/- 0.8 versus 2.1 +/- 0.9). The vast majority of patients with hypertrophic cardiomyopathy (91 [82%] of 111) showed evidence of impaired left ventricular diastolic performance, as assessed from the Doppler waveform. Abnormal Doppler diastolic indexes were identified with similar frequency in patients with (78%) or without (83%) left ventricular outflow obstruction, as well as in patients with (84%) or without (80%) cardiac symptoms. However, patients with nonobstructive hypertrophic cardiomyopathy showed more severe alterations in the Doppler indexes of diastolic function than did patients with obstruction. Thus, abnormal diastolic performance as assessed by Doppler echocardiography was apparent in the vast majority of the study patients with hypertrophic cardiomyopathy, independent of the presence or absence of cardiac symptoms or a subaortic pressure gradient. The high frequency with which diastolic abnormalities are identified in asymptomatic patients with hypertrophic cardiomyopathy suggests that impaired diastolic performance may be present at a time in the natural history of the disease when functional limitation is not yet evident.
Adolescent↗
Increased nuclear proto-oncogene expression in hypertrophic cardiomyopathy.
Hypertrophic cardiomyopathy is characterized by an unexplained hypertrophy of the left ventricle, particularly the interventricular septum. Although point mutations in the beta-myosin chain gene have been found in several US families in familiar hypertrophic cardiomyopathy, the pathogenetic pathways leading to myocyte hypertrophy, the most important feature, are still not clear. To examine whether activation (expression) of nuclear proto-oncogenes may play a role in hypertrophic cardiomyopathy, endomyocardial biopsies from 13 patients with hypertrophic cardiomyopathy were examined using monoclonal antibodies against c-myc, c-fos and c-jun. The nuclear proto-oncogenes c-fos, c-jun and c-myc were expressed in 53, 60, and 50%, respectively, of patients with hypertrophic cardiomyopathy. In control biopsies, c-myc was detectable in only 10% of the patients, while c-fos and c-jun were always undetectable. These results show that nuclear proto-oncogenes are induced in patients with hypertrophic cardiomyopathy, although the triggering mechanisms remain unknown.
Antibodies, Monoclonal↗
[Hypertrophic cardiomyopathy].
Hypertrophic cardiomyopathy is a heterogeneous, progressive disease with a variable age of debut. Hypertrophic cardiomyopathy is characterized by myocardial hypertrophy with a bizarre fibre disarray. Angina pectoris, dyspnoea and syncope are the most frequent symptoms. Hypertrophic cardiomyopathy is an important cause of sudden death, especially in children and young adults. The aetiology is genetic in more than 60% of the cases, with an autosomal dominant mode of inheritance. More than 50 different mutations involving six genes have so far been associated with the development of hypertrophic cardiomyopathy. These mutations are located to genes coding for several of the proteins in the cardiac sarcomere. The protein changes seem to compromise contractility as well as sarcomere assembly, thereby secondarily causing compensatory hypertrophy. The management of hypertrophic cardiomyopathy has been markedly improved within the last few years. This emphasizes the importance of determining prognostic markers in each patient. A specific genetic diagnosis may prove to be of major importance.
Adult↗
Assessing a murmur, saving a life: current trends in the management of hypertrophic cardiomyopathy.
Hypertrophic cardiomyopathy, formerly called idiopathic hypertrophic subaortic stenosis (IHSS), is the leading cause of sudden cardiac death in young people. Hypertrophic cardiomyopathy is a non-dilated cardiomyopathy primarily affecting the left ventricle, left atria, intraventricular septum, and mitral valve. It is an autosomal dominant genetic disorder that impairs diastolic and systolic function. Diagnosis is complex due to the heterogeneity of the disease. Symptoms and morphology are not always related and clinical signs may be absent or limited to a soft systolic murmur. The first symptom of hypertrophic cardiomyopathy is frequently sudden cardiac death. Echocardiogram is an accurate diagnostic tool. Asymptomatic patients are generally not treated. Treatment for symptomatic patients begins with beta or calcium channel blockers. Antiarrhythmics may be added to protect against sudden cardiac death. Surgical intervention is done if other treatments fall and involves removal of a portion of the obstructive septum. Operative mortality is 5% with a 60% reduction in symptoms. A promising alternative to surgery is dual-chamber pacemakers. Patient and family teaching is the emphasis of long-term management.
Adolescent↗
[Myocardial interstitial fibrosis and diastolic dysfunction in hypertrophic cardiomyopathy].
Hypertrophic cardiomyopathy is an autosomal dominant disease characterized by asymmetrical left ventricular hypertrophy, myocyte disarray, interstitial fibrosis, and small vessel disease. More than 100 mutations in 10 genes, all encoding for sarcomeric proteins, have been identified as responsible for this disease. While the etiology of hypertrophic cardiomyopathy has been extensively elucidated, its pathogenesis is not completely understood. Mutated proteins are incorporated in the sarcomere and impair myocyte contractility. This probably triggers the compensatory local release of trophic factors, which influence the development of the typical anatomical features of the disease. Modifying genes or the effect of environmental or local factors is likely to play a role. Interstitial fibrosis is a morphological characteristic of hypertrophic cardiomyopathy and, increasing chamber stiffness, is an important determinant of diastolic dysfunction. Studies on transgenic animals with hypertrophic cardiomyopathy emphasize the role of interstitial fibrosis in this disease. Recently our group has shown that collagen turnover, evaluated through serum markers of collagen metabolism, is more active in patients with hypertrophic cardiomyopathy than in normal subjects and that patients with passive diastolic dysfunction accumulate collagen I. These studies are potentially relevant as they allow to assess the effects of therapy with cardioreparatory drugs.
Cardiomyopathy, Hypertrophic↗
Calcium-antagonist receptors in the atrial tissue of patients with hypertrophic cardiomyopathy.
Hypertrophic cardiomyopathy is characterized by a nondilated, hypertrophied left ventricle in the absence of any overt cause. A possible role of adrenergic innervation or of cellular calcium regulation is suggested by the presence of hyperdynamic left ventricular function and by the clinical and symptomatic improvement seen in patients treated with beta-receptor antagonists or calcium antagonists. Therefore, we measured the density of calcium-antagonist receptors and beta-adrenoceptors in the atrial myocardium of 16 patients with hypertrophic cardiomyopathy and 19 patients with various other cardiac disorders. For comparison, we also measured the number of voltage-sensitive sodium channels. Calcium-antagonist binding sites, measured as the amount of dihydropyridine bound to atrial tissue, were increased by 33 percent in patients with hypertrophic cardiomyopathy (mean [+/- SD], 397 +/- 104 fmol per milligram of protein in patients with hypertrophic cardiomyopathy, as compared with 299 +/- 108 in patients with other cardiac disorders; P less than 0.01). The densities of saxitoxin-binding sites on voltage-sensitive sodium channels and beta-adrenoceptors were the same in the two groups, although the density of beta-adrenoceptors was higher in atrial samples from patients receiving beta-receptor antagonists (165 +/- 86 fmol per milligram of protein [patients receiving beta-blockers] vs. 85 +/- 60 [patients not receiving beta-blockers]; P less than 0.04). The increase in the number of calcium-antagonist receptors in hypertrophic cardiomyopathy suggests that abnormal calcium fluxes through voltage-sensitive calcium channels may play a pathophysiologic part in the disease.
Adolescent↗
Hypertrophic cardiomyopathy.
Hypertrophic cardiomyopathy is a diverse clinical and pathophysiologic disorder of unknown cause that principally involves the left ventricle and is manifested as asymmetric or concentric hypertrophy. If asymmetric, the hypertrophy is usually greatest in the ventricular septum, but variations occur in which the hypertrophy may be maximal at the mid-ventricular level, at the apex, 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 systolic anterior motion (SAM) of the anterior or posterior mitral leaflet(s) with mitral leaflet-septal contact. SAM occurs as the result of the Venturi forces created by the rapid ejection of blood through an outflow tract that is narrowed by upper septal hypertrophy, drawing the mitral leaflet(s) anteriorly. 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. Ventriculomyectomy 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. In symptomatic patients with resting obstruction this form of surgery more dramatically relieves the systolic abnormalities and the accompanying symptoms than any form of medical therapy currently available. The extent of hypertrophy is believed to be the principal determinant of impaired left ventricular relaxation and increased chamber stiffness that characterize diastole in hypertrophic cardiomyopathy. Diastolic dysfunction is common to most such patients irrespective of the presence or absence of outflow obstruction. Calcium entry blockers may improve the left ventricular relaxation process and relieve symptoms in patients with hypertrophic cardiomyopathy, particularly the subgroup with no obstruction to outflow. Atrial and ventricular arrhythmias are responsible for a significant proportion of the morbidity and mortality, and their prevalence appears to depend on the presence of obstruction and the extent of hypertrophy. Thus, the major manifestations of hypertrophic cardiomyopathy in systole and diastole, as well as the disturbances in rhythm, appear to be related to the site and/or extent of the hypertrophic process. We have learned much about hypertrophic cardiomyopathy in the 30 years since its modern description. The vast majority of symptomatic patients can now be improved with specific medical or surgical therapy.(ABSTRACT TRUNCATED AT 400 WORDS)
Arrhythmias, Cardiac↗
Missense mutation of the beta-cardiac myosin heavy-chain gene in hypertrophic cardiomyopathy.
Hypertrophic cardiomyopathy occurs as an autosomal dominant familial disorder or as a sporadic disease without familial involvement. We describe a missense mutation of the beta-cardiac myosin heavy chain (MHC) gene, a G to T transversion (741 Gly-->Trp) identified by direct sequencing of exon 20 in four individuals affected with familial hypertrophic cardiomyopathy. Three individuals with sporadic hypertrophic cardiomyopathy, whose parents are clinically and genetically unaffected, had sequence variations of exon 34 of the alpha-cardiac MHC gene (a C to T transversion, 1658 Asp-->Asp, resulting in FokI site polymorphism), of intron 33 of the alpha-cardiac MHC gene (a G to A and an A to T transversion), and also of intron 14 of the beta-cardiac MHC gene (a C to T transversion in a patient with Noonan syndrome). Including our case, 30 missense mutations of the beta-cardiac MHC gene in 49 families have been reported thus far worldwide. Almost all are located in the region of the gene coding for the globular head of the molecule, and only one mutation was found in both Caucasian and Japanese families. Missense mutations of the beta-cardiac MHC gene in hypertrophic cardiomyopathy may therefore differ according to race.
Adolescent↗
Persistent ST segment elevation: a new ECG finding in hypertrophic cardiomyopathy.
Hypertrophic cardiomyopathy is a primary disease of myocardium resulting in myocardial hypertrophy without any inciting pressure or volume overload. The typical triad of symptoms includes exertional angina, syncope, and shortness of breath. Sudden cardiac death, the most dreadful complication of this disorder, can be the first manifestation of the disease and is more common in young patients. Elderly patients, on the other hand, may have a relatively benign course with normal or near-normal life span. The electrocardiogram (ECG) and echocardiography are the two most useful measures to diagnose hypertrophic cardiomyopathy. The electrocardiographic features of hypertrophic cardiomyopathy are numerous, including ST segment elevation that may simulate other ST segment elevation syndromes, including acute myocardial infarction, variant angina pectoria, acute pericarditis, bundle branch blocks, ventricular paced rhythm, dyskinetic ventricular segment, ventricular aneurysm, left ventricular hypertrophy, Wolff-Parkinson-White syndrome, and early repolarization syndrome. This report describes a case of an asymptomatic patient who presented with ST segment elevation of acute injury type and, therefore, was admitted to rule out silent myocardial infarction. Myocardial infarction was ruled out by cardiac enzyme levels, but ST segment elevation remained persistent in all of the subsequent ECGs. Echocardiography was performed, which clearly showed hypertrophic cardiomyopathy with left ventricular outflow tract obstruction and a high intracavity pressure gradient. Subsequently, retrieval of old ECGs showed a similar type of ST segment elevation in the patient's previous ECGs.
Cardiomyopathy, Hypertrophic↗
Hypertrophic cardiomyopathy.
Hypertrophic cardiomyopathy is a fascinating disease of marked heterogeneity. Hypertrophic cardiomyopathy was originally characterized by massive myocardial hypertrophy in the absence of known cause, a dynamic left ventricular outflow obstruction, and increased risk of sudden death. It is now well accepted that multiple mutations in genes encoding for the cardiac sarcomere are responsible for the disease. Complex morphologic and pathophysiological differences, disparate natural history studies, and novel treatment strategies underscore the challenge to the practicing cardiologist when faced with the management of the patient with hypertrophic cardiomyopathy.
Cardiomyopathy, Hypertrophic↗
Does treatment influence the natural history of patients with hypertrophic cardiomyopathy?
Hypertrophic cardiomyopathy is a cardiac disorder of unknown aetiology which is characterised by hypertrophy of a non-dilated left ventricle. The course of hypertrophic cardiomyopathy may be relatively benign, but the risk of sudden death due to ventricular arrhythmias is an important clinical problem. Those patients at greatest risk of sudden death appear to be those with the combination of diagnosis in childhood, a family history of hypertrophic cardiomyopathy and sudden death, and syncopal episodes. The treatment of hypertrophic cardiomyopathy-associated ventricular tachycardia with 'conventional' antiarrhythmic agents (disopyramide, quinidine, mexiletine) has seldom been successful. However, treatment of this arrhythmia with amiodarone in well-matched but non-parallel groups of patients has resulted in suppression of arrhythmia and improved survival compared with that seen with 'conventional' antiarrhythmic agents.
Amiodarone↗
Hypertrophic cardiomyopathy.
Hypertrophic cardiomyopathy is a multigenetic cardiac disease with autosomal dominant pattern of inheritance and incomplete penetrance, with the exclusion of those cases caused by mutations in the mitochondrial genome. The disease is usually caused by mutations in several sarcomeric contractile protein genes. Mutations have been found in four genes that encode components of the thick filament: beta myosin heavy chain (5), essential myosin light chains (6), regulatory myosin light chains (6), and cardiac myosin binding protein -C (7), (8); in five genes that encode thin filament proteins: cardiac actin (9), cardiac troponin T (10), cardiac troponin C (11), cardiac troponin I (12), and alpha-tropomyosin (10); and in the sarcomeric cytoskeletal protein titin (13). In addition to mutations in contractile sarcomeric proteins, mutations in other genes encoding for non-sarcomeric proteins also have been identified in patients with-non pure form of hypertrophic cardiomyopathy. As a complex cardiac disease, hypertrophic cardiomyopathy has unique pathophysiological characteristics and a various morphological, functional, and clinical features.
Cardiomyopathy, Hypertrophic↗