Race, gender and clinical presentation in apical hypertrophic cardiomyopathy

Funding Acknowledgements

Type of funding sources: None.

Background

The apical variant of hypertrophic cardiomyopathy (ApHCM) has male predominance and is a relatively rare phenotype in Western population. Characteristics of female and black patients diagnosed with ApHCM are very limited in the existing literature.

Purpose

We aimed to investigate whether gender and race are associated with a different clinical presentation and CMR findings in apical HCM.

Methods

We retrospectively analysed 150 patients (113 males and 37 females) with a diagnosis of apical HCM who have been followed in our inherited cardiac conditions (ICC) clinic between 2010 and 2020. Only patients with a CMR study and apical hypertrophy defined as ≥ 13mm at the time of diagnosis were included.

Demographics and clinical characteristics were obtained from electronic records. Volumetric CMR data were taken from confirmed reports while other parameters were measured by standard protocol. "Pure" ApHCM was defined as isolated apical hypertrophy and "mixed" with both apical and septal hypertrophy but with the apex thickest (1). Apical displacement of papillary muscles (PM) was defined when the base of PM originated from the apical one-third of the left ventricle (LV) in the apical 4- or 2-chamber views. Giant T-wave inversion was defined as T-wave inversion that is equal or greater than 10 mm (1 mV) in any electrocardiogram lead.

Results

Our study population included patients of White (55, 37%), Black (37, 25%), Asian (36, 24%) and Mixed/Others (22, 15%) ethnicity.  Black patients were more likely to have a diagnosis of hypertension at presentation when compared to White (70% vs 40%, p = 0.01) and to Asian and Mixed/Other patients (70% vs 48%, p = 0.03). Similarly, they were more likely to have "mixed" ApHCM than White (49% vs 20%, p = 0.003) and Asian and Mixed/Other (49% vs 26%, p = 0.02) patients.

Females were diagnosed at an older age (63 ± 12 vs 52 ± 14, p < 0.001) and were less likely to have deep T-wave inversion on their ECG at presentation (14% vs 32%, p = 0.03) compared to their male counterparts. Females in this cohort also had higher representation of black ethnicity and were more likely to have hypertension (68% vs 47%, p = 0.03). Apart from the expected gender related differences in volumes and LV mass, there were no differences in cardiomyopathy-specific parameters we investigated.

Conclusions

In our cohort, females with ApHCM presented at an older age and were less likely to have giant T-wave inversion on ECG. Black patients with ApHCM were more likely to have hypertension and the "mixed" type of the disease.

P3683Diagnosis of arrhythmogenic cardiomyopathy and overlap with cardiac adaptation to exercise: insights from a cardiac magnetic resonance study

Background

The diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC) is often challenging and some structural abnormalities typical of the disease may overlap with changes reflective of cardiac adaptation to exercise.

Purpose

The aim of the study was to assess the performance of the cardiac magnetic resonance (CMR) 2010 Task Force Criteria (TFC) in a cohort of patients with definite diagnosis of ARVC and define the overlap with a cohort of highly trained athletes of similar age and sex.

Methods

We compared the CMR features of 43 patients (mean age 49±17 years, 49% males, 32 (74%) genotyped) with a definite diagnosis of ARVC according to the revised TFC to 97 (mean age 45±16 years, 61% males) highly-trained athletes of similar age and sex, in whom cardiac disease was excluded after comprehensive work-up.

Results

The CMR was abnormal in 37 (86%) patients. The right ventricle (RV) was affected in isolation in 17 (39%) patients, with 18 (42%) patients exhibiting biventricular involvement and 2 (5%) patients showing isolated left ventricular (LV) involvement. The most common RV abnormalities were regional wall motion abnormalities (RWMA) (n=34; 79%), RV dilatation fulfilling a major or minor volume TFC (n=18; 42%), impaired systolic function (RV ejection fraction (EF) ≤45%: n=17; 40%) and myocardial fibrosis (n=13; 30%). The predominant LV abnormality was myocardial fibrosis (n=20; 47%), with a small proportion of patients exhibiting RWMA (n=6; 14%) and impaired systolic function (LVEF <50%: n=6; 14%). Twenty-three (53%) patients fulfilled a major (n=14; 32%) or a minor (n=9; 21%) CMR TFC. Sixteen (16%) athletes exceeded the cut-off values for RV volumes used as a major (n=10; 10%) or a minor (n=6; 6%) TFC with an inverse relationship between age and RV volumes (r=−41, p=0.001). None of the athletes fulfilled the TFC for RV ejection fraction. Applying the CMR TFC to the ARVC patient population showed a sensitivity of 33% for the major and 28% for the minor criteria. Applying the RV volume and systolic function TFC values in the entire study population showed a sensitivity of 53%, a specificity between 83% and an accuracy of 0.68.

Conclusions

The great majority (86%) of patients with ARVC demonstrates structural abnormalities suggestive of cardiomyopathy on CMR but only 53% fulfills any of the CMR TFC. Only a small proportion (16%) of older athletes demonstrate significant RV dilatation that overlaps with the volume criteria for ARVC, in juxtaposition to younger athletes who exhibit a greater degree of overlap. The emergence of ARVC as a biventricular disease provides an opportunity to re-evaluate the diagnostic criteria and include LV involvement in conjunction with RV involvement to improve diagnostic accuracy.

Acknowledgement/Funding

CRY (Cardiac Risk in the Young) charity

Porcelain adherence to dental cast CP titanium: effects of surface modifications

OBJECTIVES

A reaction layer forms on cast titanium surfaces due to the reaction of the molten titanium with the investment material. Such a layer prevents strong adhesion between titanium and porcelain. This study characterized the effects of surface modifications on cast titanium surfaces and titanium-ceramic adhesion.

METHODS

ASTM grade II CP titanium was cast into an MgO-based mold. Castings were devested by sandblasting with alumina particles, and subjected to surface modification by immersion in one of the following solutions: (1) 35% HNO3-5% HF at room temperature for 1min; (2) 50% NaOH-10% CuSO4 x 5H2O at 105 degreesC for 10min; (3) the NaOH-CuSO4 solution followed by the HNO3-HF solution; (4) 50% NaOH-10% NaSO4 at 105 degreesC for 10 min; (5) the NaOH-NaSO4 solution followed by the HNO3-HF solution; and (6) 50% NaOH solution at 105 degreesC for 10min. Surfaces only sandblasted with alumina were used as controls. Specimen surfaces were characterized by XRD and SEM/EDS, and hardness-depth profiles were determined. All specimens were sandblasted with 110 microm alumina particles before porcelain firing. An ultra-low-fusing porcelain (Vita Titankeramik) was fused on the titanium surfaces. The titanium-ceramic adhesion was characterized by a biaxial flexure test, and area fraction of adherent porcelain (AFAP) was determined by X-ray spectroscopy.

RESULTS

EDS analyses revealed a substantial amount (13-17 wt%) of Al on the control, and specimens modified with Methods 2, 4, and 6. XRD revealed residual stress in the titanium surfaces and corundum on the control, and Methods 2, 4, and 6 specimens. A new Ti(Cu, Al)2 phase was identified on the titanium surfaces modified by immersion in 50% NaOH-10% CuSO4 x 5H2O aqueous solution. Reduced residual stress was observed on Method 1, 3, and 5 specimens. No corundum peaks were detected on these specimens. Compared to the control, significantly lower (P < 0.05) hardness values were found for Methods 1-3 and Method 5 specimens at 20 microm below the surfaces and for Method 1-5 specimens at 50 microm below the surfaces. Significantly higher (P < 0.05) AFAP values were found for surfaces modified with Methods 2-6 compared to the control and Method 1, and no significant differences were found among Methods 1-6, and between control and Method 1.

SIGNIFICANCE

Based on the results from the present study, porcelain adherence to cast CP titanium can be improved by the caustic baths used in the study.

Molecular cloning and characterization of 13 out genes from Erwinia carotovora subspecies carotovora: genes encoding members of a general secretion pathway (GSP) widespread in gram-negative bacteria

The chemical mutagen ethylmethanesulphonate (EMS) has been used to generate mutants of Erwinia carotovora subspecies carotovora which are defective in the secretion of pectinases (Pel) and cellulases (Cel) but unaltered for protease (Prt) secretion. Such mutants, called Out-, still synthesize Pel and Cel but these enzymes accumulate within the periplasm. Cosmid clones carrying wild-type E. carotovora ssp. carotovora DNA, identified by their ability to restore the Out+ phenotype when transferred to some Out- mutants, were classified into six complementation groups using cosmids and cosmid derivatives. Analysis of the nucleotide sequence of a 12.7 kb DNA fragment, encompassing complementing cosmid inserts, revealed a coding capacity for 13 potential open reading frames (ORFs), and these were designated outC-outO. Some of the out gene products were visualized using a T7 gene 10 expression system. The predicted Out proteins are highly similar to components of extracellular enzyme secretion systems from a diverse range of eubacteria including Erwinia chrysanthemi, Klebsiella oxytoca, Aeromonas hydrophila, Pseudomonas aeruginosa and Xanthomonas campestris. Lower levels of similarity exist between Ecc Out proteins and components of macromolecular trafficking systems from Bacillus subtilis, Haemophilus influenzae, Agrobacterium tumefaciens, Yersinia pestis and a protein involved in the morphogenesis of filamentous bacteriophages such as M13.

Short tandem repeats shared by B- and C-hordein cDNAs suggest a common evolutionary origin for two groups of cereal storage protein genes

We have identified cDNA clones coding for the major sulphur-rich and sulphur-poor groups of barley storage proteins (the B- and C-hordeins, respectively). Hybridization studies have revealed unexpected homologies between B- and C-hordein mRNAs. Using a deletion mutant (Risø 56), we have mapped some C-hordein-related sequences within, or closely associated with, B-hordein genes at the Hor 2 locus. Nucleotide sequencing has shown that the primary structure of B-hordein polypeptides can be divided into at least two domains: domain 1 (repetitive, proline-rich, sulphur-poor), which is homologous to C-hordein sequences, and domain 2 (non-repetitive, proline-poor, sulphur rich), which makes up two-thirds of the polypeptide and is partially homologous to a 2S globulin storage protein found in dicotyledons. The coding sequences that are homologous in B- and C-hordein mRNAs have an asymmetric base composition (>80% C-A) and are largely composed of a degenerate tandem repeat based on a 24 nucleotide consensus that encodes Pro-Gln-Gln-Pro-Phe-Pro-Gln-Gln. We discuss the evolutionary implications of the domain structure of the B-hordeins and the unusual relationship between the two groups of barley storage proteins.