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Background: The transapical approach has been utilized in adult HCM patients with either midventricular obstruction or a small LV cavity; however, there are little data on its use in children., Methods: We retrospectively reviewed all patients (age <21 years) with HCM who underwent a transapical myectomy from January 2002 to December 2016. Indication for surgery was midventricular obstruction in 19/23 (83%) and small LV cavity in 4 (17%). Preoperative symptoms included: dyspnea (96%), chest pain (65%), presyncope (61%), and syncope (35%). The mean age at the time of operation was 14 ± 4.0 years (range, 4-20)., Results: Overall, 23 patients (12 males) underwent transapical myectomy. A concomitant transaortic approach was performed in 16/19 (84%) with obstruction. The intraventricular gradient decreased from 71 mm Hg (IQR 44-92 mm Hg) preoperatively to 18 mm Hg (IQR 8-34 mm Hg, P < .0001) after myectomy. In patients with a small LV cavity, the mean left ventricular end diastolic dimension (LVEDD) increased from 40 ± 3 mm to 46 ± 3 mm (P = .05) after myectomy. There were no early deaths. Postoperative morbidity included complete heart block in 3 patients, 2 of which required pacemakers. Median follow up was 3.5 years (IQR 1.6-5.6). Symptoms improved in 95% of patients; the number of patients in NYHA class 3 or 4 heart failure decreased from 10/23 (43%) preoperatively to 3/23 (13%) postoperatively (P < .0001). Overall survival at 5 years postsurgery was 100%. Transplant-free survival was 91% and 87% at 1 and 5 years, respectively., Conclusion: In children with HCM, transapical myectomy is an effective adjunct to a transaortic approach to abolish midventricular obstruction and it effectively increases LV stroke volume in patients with small LV cavities and nonobstructive HCM. It may be beneficial for these patients with significant symptoms and who have failed medical therapy as a treatment alternative to cardiac transplantation., (© 2018 Wiley Periodicals, Inc.)

Objective: Hypertrophic cardiomyopathy is underscored by profound phenotypic and genotypic heterogeneity. Echocardiographically, hypertrophic cardiomyopathy can be categorized into four morphological subtypes: reverse curve, sigmoidal, neutral contour, and apical variant. Previous studies indicate that reverse curve hypertrophic cardiomyopathy is the strongest predictor of a positive genetic test. Little is known about the spectrum and prevalence of mutations and genotype-phenotype correlations in apical hypertrophic cardiomyopathy., Design: Between 1999 and 2007, 1053 patients with the diagnosis of hypertrophic cardiomyopathy (60% male, age at diagnosis 44.4 ± 19 years) underwent sarcomeric genetic testing. Blinded to the genetic test results, each echocardiogram was scored for septal morphology and phenotyping was performed using the patient's medical record. Subset analysis was performed to elucidate the genotype, phenotype, and outcome of apical hypertrophic cardiomyopathy., Results: Overall, 71 patients (7%) had apical hypertrophic cardiomyopathy on echocardiography (63% male, mean age 47.8 ± 15 years, mean left ventricular wall thickness 19.8 ± 6 mm). Left ventricular outflow tract obstruction was uncommon (seven patients; 10%). Eighteen patients (25%) had a positive genetic test, with the majority of mutations found in MYBPC3 (six; 35%) and MYH7 (six; 35%). Follow-up was available on 68 patients (96%) with a median age of 57.3 years (range 19.3-82 years). Mean follow-up was 5.5 years (range 0.1-18.2 years). There was no statistical difference between the occurrence rates of adverse events between genotype-positive and genotype-negative groups., Conclusions: In this largest cohort of patients with genetic testing for hypertrophic cardiomyopathy, <10% exhibited apical disease. This least common subtype was associated with a negative genetic test result 75% of the time. In contrast to prior publications suggesting a predilection for ACTC1/TPM1 mutations in patients with apical hypertrophic cardiomyopathy, the two most common genotypes (MYBPC3-HCM and MYH7-HCM) remained most common among patients who had a positive genetic test., (© 2014 Wiley Periodicals, Inc.)