31 Apical hypertrophic cardiomyopathy: the variant less known

IntroductionHypertrophic cardiomyopathy (HCM) is a heterogenous disease. Apical HCM is a comparatively rare subtype. Apical HCM tends to be sporadic with different clinical features and lower frequency of detected gene mutations [figure 1]. We evaluated the spectrum of apical HCM-associated gene mutations, genotype–phenotype correlations, and clinical outcomes of patients in our cohort.Methods30 patients (29 probands) with apical HCM were retrospectively identified at a specialist cardiomyopathy clinic. Records were reviewed and variables were recorded including: demographics, clinical characteristics, family history, presenting symptoms, device therapy, arrhythmia burden, and other co-morbidities. ECG, cardiac imaging and genetic test results were analyzed.ResultsThe group consisted of 21/30 (70%) men; mean age 57 years. 3 probands (10.3%) in the study had a family history of HCM. Another 3 probands (10.3%) had a family history of sudden cardiac death in a first degree relative. Women were older than men at initial visit, 57 years versus 49 years. Of the 26 patients who had an ECG available for analysis, all were abnormal by established criteria. Female patients were more likely to have a family history of HCM (22% versus 4.7% of males). They have a higher burden of symptoms and higher rates of mid-cavity obstruction compared to males (88% versus 33%). Genetic analysis was performed on 24/30 patients (80%).The results are summarized in table 1. 75% of female probands had a pathogenic variant in a sarcomere gene. No male proband had a sarcomere mutation. One male relative of a female proband inherited the familial MYBPC3 mutation.Abstract 31 Figure 1Apical HCM ECG[Figure omitted. See PDF]Abstract 31 Table 1Genotypes of apical HCMAAD Sex Presentation FHx SCD Mutation 63 F Palpitations No No MYBPC3 p.Arg502Gln 68 F Palpitations No No MYH7 p.Arg1079Gln 66 F Palpitations No No TNNI3 p. Arg162Gln 61 F Palpitations Apical No MYBPC3 p.Lys814del 21 F Syncope Septal No TNNI3 p.Arg 141Gln 16 F Syncope LVNC Yes ACTC1 p.Glu101Lys 41 M Family screening Apical No MYBPC3 c.2441_2443delAga 59 M Chest pain No No PTPN11 p.Thr468Met 47 M Chest pain No No SCL22A5 p. Arg83Le AAD: age at diagnosis, FHx : family history of apical or classical HCM or other cardiomyopathy, SCD in a first degree relative from HCMConclusionThe two most commonly affected genes in our cohort were MYBPC3 (3 patients) and TNNI3 (2 patients), with mutations also found in MYH7, ACTC1, PTPN11 and SCL22A5 [