Numerical Simulation Study on the Mechanism of Formation of Apical Aneurysm in Hypertrophic Cardiomyopathy With Midventricular Obstruction

Apical aneurysm was observed to be associated with midventricular obstruction (MVO) in hypertrophic cardiomyopathy (HCM). To investigate the genesis of the apical aneurysm, the idealized numerical left ventricular models (finite-element left ventricle models) of the healthy left ventricle, subaortic obstruction, and midventricular obstruction in HCM of left ventricle were created. The mechanical effects in the formation of apical aneurysm were determined by comparing the myofiber stress on the apical wall between these three models (healthy, subaortic obstruction, and midventricular obstruction models). In comparing the subaortic obstruction model and MVO model with HCM, it was found that, at the time of maximum pressure, the maximum value of myofiber stress in MVO model was 75.0% higher than that in the subaortic obstruction model (654.5 kPa vs. 373.9 kPa). The maximum stress on the apex of LV increased 79.9, 69.3, 117.8% than that on the myocardium around the apex in healthy model, subaortic obstruction model, and MVO model, respectively. Our results indicated that high myofiber stress on the apical wall might initiate the formation process of the apical aneurysm.

Efficacy of Everolimus Low-Dose Treatment for Cardiac Rhabdomyomas in Neonatal Tuberous Sclerosis: Case Report and Literature Review

Background: Cardiac rhabdomyomas (CRs) are the most common cardiac tumors in newborns. Approximately 80–90% of cases are associated with tuberous sclerosis complex (TSC). In selective cases, Everolimus has resulted in a remarkable tumoral regression effect in children with TS. The optimal dosage for neonates is still unknown. Case presentation: We describe the use of Everolimus in a neonate with multiple biventricular CRs, causing subaortic obstruction, in which a low-dose treatment (0.1 mg/die), in an effort to maintain serum trough levels of 3–7 ng/mL, was successfully used off-label, without adverse effects. Conclusions: We showed that a low-dose Everolimus regimen may be an effective and safe treatment for CR regression in TS neonates, when the minimum therapeutic range was maintained.

Surgical treatment for the single ventricle with subaortic obstruction. Clinical case of the Damus-Kaye-Stansel procedure

We present a case of hemodynamic correction for the single ventricle combined with subaortic obstruction and coarctation in an infant. The Damus-Kaye-Stansel procedure with modified double-barrel technique was performed. The pulmonary flow was provided with modified Blalock-Taussig shunt. The early postoperative period was characterized by multiple organ failure. Subsequently, the infant underwent the next stages of hemodynamic correction with good long-term results.

Comment on "Surgical treatment for the single ventricle with subaortic obstruction. Clinical case of the Damus-Kaye-Stansel procedure"

.

Primary prevention of sudden cardiac death in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) has been regarded as the most common non-trauma-related cause of sudden cardiac death (SCD) in young people, including competitive athletes. The traditional clinical profile of HCM patients at highest risk of SCD is largely comprised of young asymptomatic patients, particularly children and adolescents. Prophylactic drug treatment to prevent SCD is ineffective and obsolete whereas the introduction of implantable cardioverter defibrillators (ICD) has changed the clinical course and natural history of the disease. The ICDs are largely responsible for reducing HCM-related mortality to 0.5%/year and have been shown to be effective despite the often complex HCM phenotype, including extreme and diverse patterns of left ventricular hypertrophy, dynamic subaortic obstruction, microvascular ischaemia, and diastolic dysfunction. An important principle related to ICD decisions in HCM patients surrounds the unpredictable nature of the arrhythmic substrate, often associated with substantial delays of 5–10 years between implant and initial intervention. Selection of patients most likely to benefit from primary prevention ICD therapy is based on non-invasive testing including echocardiography or cardiac magnetic resonance imaging, history taking, exercise testing, and ambulatory electrocardiogram (ECG). Conventional risk markers are (1) family history (one or more HCM-related SCDs in close relatives); (2) recent unexplained syncope; (3) multiple repetitive (or prolonged) non-sustained ventricular tachycardia on ambulatory ECG; (4) massive left ventricular hypertrophy (wall thickness ≥30 mm); and (5) hypotensive blood pressure response to exercise, although this is not a sole indication for ICD implants. ICD decisions within current risk stratification guidelines can be challenging, particularly in patients with just one risk factor or when available evidence is ambiguous or insufficient to assign SCD risk level with confidence.