Sustained arrhythmias in hypertrophic obstructive cardiomyopathy

Patients with hypertrophic obstructive cardiomyopathy are subject to syncope and sudden death. Ambulatory monitoring discloses frequent and complex ventricular ectopy in many of these patients, and the occurrence of ventricular tachycardia suggests an increased risk of sudden death. We prospectively evaluated whether induced sustained arrhythmia could explain episodes of cerebral dysfunction in hypertrophic cardiomyopathy. Seven consecutive symptomatic patients (six of whom had an intraventricular gradient of 40 to 130 mm Hg) were subjected to atrial and ventricular stimulation. An electrophysiologic abnormality that would explain the symptoms was identified in every patient: supraventricular tachycardia was present in two, sustained ventricular tachycardia in three, ventricular fibrillation in one, and a prolonged QT interval and dispersion of ventricular refractoriness in one. Antiarrhythmic drugs were selected on the basis of the response to electrophysiologic testing. There has been no recurrence of symptoms in 120 patient-months of follow-up. This experience suggests that arrhythmias are the principal cause of syncope or sudden death in obstructive cardiomyopathy and that electrophysiologic study may be useful in selecting prophylactic therapy.     

Isolated right ventricular hypertrophic obstructive cardiomyopathy

Two cases of isolated hypertrophic cardiomyopathy of right ventricle without any involvement of interventricular septum or left ventricle are reported. Two cases reported in literature are also reviewed. In these cases symptoms are those of left ventricular hypertrophic obstructive cardiomyopathy. Right ventricular dominance on clinical examination and electrocardiogram and inspiratory increase in intensity of murmur are helpful clues. 2-Dimensional echocardiography with Doppler evaluation can confirm the diagnosis noninvasively.     

Noonan syndrome with hypertrophic obstructive cardiomyopathy

A case of a 20 years old female who had Noonan syndrome associated with obstructive cardiomyopathy was presented. It is well known that Noonan syndrome is frequently complicated with cardiac anomaly, and although no autopsies were performed two cases have been diagnosed clinically as Noonan syndrome accompanied with idiopathic cardiomyopathy in our country. The present case would be the first autopsied case in Japan of Noonan syndrome associated with idiopathic obstructive cardiomyopathy.     

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.     

Specificity of cellular and myofibrillar disorientation in hypertrophic obstructive cardiomyopathy

The specificity of the ultrastructural myocardial abnormalities in hypertrophic obstructive cardiomyopathy (HOCM) is undetermined. We undertook a quantitative study using myocardial biopsy specimens from the subaortic area in a patient with classical HOCM and compared them with hypertrophic left ventricular myocardium from a patient suffering from rheumatic valve disease. Myofibrillar disarray and side-to-side junctions were chosen as strictly quantifiable features. The former was seen as representing intracellular disorganization; the latter was seen as criterion for intercellular disorganization. The results showed that there is no preference for these abnormalities to occur in HOCM. Indeed, intracellular abnormalities more frequently occurred in the hypertrophic myocardium the patient without HOCM. Neither intracellular nor intercellular features can be regarded as specific for HOCM, even in a quantitative sense.     

室间隔射频消融术在梗阻性肥厚型心肌病中的应用

目的探讨室间隔射频消融术(PIMSRA)治疗梗阻性肥厚型心肌病(HOCM)的临床效果。方法收集2019年6~8月于我院心血管内科行PIMSRA的7例HOCM患者的临床资料,回顾分析该治疗方法的手术要点、术后管理重点和随访结果。结果7例患者手术均获成功,术中、术后未出现严重并发症,术后左心室流出道压力阶差下降明显,超声显示二尖瓣前叶收缩期前向运动现象明显减轻。出院后15 d、2个月、3个月随访,7例患者生存良好,疾病症状均缓解,心功能分级均有改善。结论PIMSRA治疗HOCM安全可靠,术后即刻可降低左室流出道压力阶差,改善患者临床症状。     

Infective endocarditis complicating hypertrophic obstructive cardiomyopathy: an unusual mural pattern

A patient with hypertrophic obstructive cardiomyopathy (HOCM) and an unusual right ventricular mural pattern of endocarditis that clinically mimicked a neoplasm is presented. To our knowledge, this is the first report of right ventricular mural endocarditis complicating HOCM.     

Surgical treatment of pediatric hypertrophic obstructive cardiomyopathy using an original approach

The authors offer an original technique of surgical correction of pediatric hypertrophic obstructive cardiomyopathy (HOCM), which allows excision of the hypertrophied area and elimination of the obstruction from the cone part of the right ventricle (RV) without penetrating into the LV cavity. 15 children aged 5 to 15 years have been operated on in Bakulev Scientific Center for Cardiovascular Surgery using this technique. 8 of the patients had simultaneous obstruction of the left and right ventricular outflow tract (LVOT and RVOT), 1 patient had RV obstruction. Medical therapy had failed in all cases. The follow-up period was 28 +/- 7 months. EchoCG examination, performed after the surgical treatment, found a decrease of the intraventricular gradient in LV from 72.9 +/- 8.9 to 12.7 +/- 5.5 mmHg; the mean gradient in RVOT also reduced from 43.6 +/- 5.7 to 4.3 +/- 2.7 mmHg. According to the EchoCG, septal thickness reduced from 31.5 +/- 6.5 to 16.5 +/- 4.1 mm. Sinus rhythm was noted in all the patients after the surgery and during the follow-up. The method proposed by the authors is preferable in surgical treatment of children with various forms of hypertrophic cardiomyopathy unresponsive to medical treatment and is a method of choice in a significant number of cases.     

Familial hypertrophic cardiomyopathy

Two genetically associated observations of the familial cardiomyopathy in a 34-year-old father and 2-day-old son are described. Verification of the lesions is performed by means of macro-and microscopic analysis including the post-mortem contrast cardioventriculography and histotopographic investigation. Specific changes in the interventricular septum and left ventricle are found in both cases as well as asymmetric hypertrophy and elimination of the cavity of the left ventricle in both father and son.     

Phenotypic diversity in hypertrophic cardiomyopathy

In recent years, the main focus of human genetic studies on hypertrophic cardiomyopathy (HCM) switched from discovering novel genes and defining disease-causing mutations to studies of mutation distribution in disease populations. Eventually these studies will define genotype-phenotype relationships, which may provide clues to understanding the disease process and help to select the most appropriate treatment strategy. Animal models engineered to recapitulate human disease provide a unique tool to investigate the pathogenic mechanisms and evaluate potential therapies. In this review, we present the spectrum of clinical HCM in the context of the genetic heterogeneity of this common human disease. Recent progress made in understanding molecular pathways that result in cardiac hypertrophy and the factors that modify these processes are discussed.     

Lack of reliable clinical predictors to identify obstructive sleep apnea in patients with hypertrophic cardiomyopathy

OBJECTIVE:

Obstructive sleep apnea is common among patients with hypertrophic cardiomyopathy and may contribute to poor cardiovascular outcomes. However, obstructive sleep apnea is largely unrecognized in this population. We sought to identify the clinical predictors of obstructive sleep apnea among patients with hypertrophic cardiomyopathy.

METHODS:

Consecutive patients with hypertrophic cardiomyopathy were recruited from a tertiary University Hospital and were evaluated using validated sleep questionnaires (Berlin and Epworth) and overnight portable monitoring. Ninety patients (males, 51%; age, 46±15 years; body mass index, 26.6±4.9 kg/m²) were included, and obstructive sleep apnea (respiratory disturbance index ≥15 events/h) was present in 37 patients (41%).

RESULTS:

Compared with the patients without obstructive sleep apnea, patients with obstructive sleep apnea were older and had higher body mass index, larger waist circumference, larger neck circumference, and higher prevalence of atrial fibrillation. Excessive daytime sleepiness (Epworth scale) was low and similar in the patients with and without obstructive sleep apnea, respectively. The only predictors of obstructive sleep apnea (using a logistic regression analysis) were age ≥45 years (odds ratio [OR], 4.46; 95% confidence interval [CI 95%], 1.47–13.54; p = 0.008) and the presence of atrial fibrillation [OR, 5.37; CI 95%, 1.43–20.12; p = 0.013].

CONCLUSION:

Consistent clinical predictors of obstructive sleep apnea are lacking for patients with hypertrophic cardiomyopathy, which suggests that objective sleep evaluations should be considered in this population, particularly among elderly patients with atrial fibrillation.