High p16 expression and heterozygous RB1 loss are biomarkers for CDK4/6 inhibitor resistance in ER+ breast cancer

CDK4/6 inhibitors combined with endocrine therapy have demonstrated higher antitumor activity than endocrine therapy alone for the treatment of advanced estrogen receptor-positive breast cancer. Some of these tumors are de novo resistant to CDK4/6 inhibitors and others develop acquired resistance. Here, we show that p16 overexpression is associated with reduced antitumor activity of CDK4/6 inhibitors in patient-derived xenografts (n = 37) and estrogen receptor-positive breast cancer cell lines, as well as reduced response of early and advanced breast cancer patients to CDK4/6 inhibitors (n = 89). We also identified heterozygous RB1 loss as biomarker of acquired resistance and poor clinical outcome. Combination of the CDK4/6 inhibitor ribociclib with the PI3K inhibitor alpelisib showed antitumor activity in estrogen receptor-positive non-basal-like breast cancer patient-derived xenografts, independently of PIK3CA, ESR1 or RB1 mutation, also in drug de-escalation experiments or omitting endocrine therapy. Our results offer insights into predicting primary/acquired resistance to CDK4/6 inhibitors and post-progression therapeutic strategies.

Association between common cardiovascular risk factors and clinical phenotype in patients with hypertrophic cardiomyopathy from the European Society of Cardiology (ESC) EurObservational Research Programme (EORP) Cardiomyopathy/Myocarditis registry

AIMS

The interaction between common cardiovascular risk factors (CVRF) and hypertrophic cardiomyopathy (HCM) is poorly studied. We sought to explore the relation between CVRF and the clinical characteristics of patients with HCM enrolled in the EURObservational Research Programme (EORP) Cardiomyopathy registry.

METHODS AND RESULTS

1739 patients with HCM were studied. The relation between hypertension (HT), diabetes (DM), body mass index (BMI), and clinical traits was analysed. Analyses were stratified according to the presence or absence of a pathogenic variant in a sarcomere gene. The prevalence of HT, DM, and obesity (Ob) was 37, 10, and 21%, respectively. HT, DM, and Ob were associated with older age (P<0.001), less family history of HCM (HT and DM P<0.001), higher New York Heart Association (NYHA) class (P<0.001), atrial fibrillation (HT and DM P<0.001; Ob p = 0.03) and LV (left ventricular) diastolic dysfunction (HT and Ob P<0.001; DM P = 0.003). Stroke was more frequent in HT (P<0.001) and mutation-positive patients with DM (P = 0.02). HT and Ob were associated with higher provocable LV outflow tract gradients (HT P<0.001, Ob P = 0.036). LV hypertrophy was more severe in Ob (P = 0.018). HT and Ob were independently associated with NYHA class (OR 1.419, P = 0.017 and OR 1.584, P = 0.004, respectively). Other associations, including a higher proportion of females in HT and of systolic dysfunction in HT and Ob, were observed only in mutation-positive patients.

CONCLUSION

Common CVRF are associated with a more severe HCM phenotype, suggesting a proactive management of CVRF should be promoted. An interaction between genotype and CVRF was observed for some traits.

Yield from family screening in a national adolescent cardiac screening program

Introduction

Cascade family screening in patients with confirmed or suspected inherited cardiac disorders is now well established. This may refute or confirm a familial clinical diagnosis and is particularly relevant in young adolescent individuals as it may be too early to manifest a distinct phenotype.

Objectives

A large cohort of 2708 adolescents aged 14–16 years gave consent to participate in a national cardiac screening program (BEAT-IT). Individuals with suspected inherited cardiac disorders were extensively evaluated. Their relatives were also invited to undergo screening. This study reports the yield of this family cardiac screening program.

Methodology

Family members of probands with suspected or confirmed inherited cardiac conditions were offered cardiac screening. A standard clinical screening protocol for all first-degree family members included a resting 12-lead ECG and echocardiogram. Those with a channelopathy suspicion also underwent postural ECGs and exercise testing. Screening second-degree relatives was also performed in a cascade fashion when clinically indicated. Relatives with a normal baseline screen were offered surveillance if younger than 25 years or a proband clinical diagnosis. Those with an abnormal ECG and/or echocardiogram were referred for further evaluation.

Results

17 probands (63% females) were suspected of harbouring inherited heart disease. Another 2 were diagnosed with a clinical phenotype. The mean age was 15.3±0.58 years. All were Caucasian.

77 family members underwent cardiac screening, with a mean age of 42.5±16.43 at first evaluation. The majority were female (n=44, 57.1%). 12 (15.6%) had an abnormal ECG. 6 (7.8%) had an abnormal echocardiogram, with 2 (2.6%) consistent with cardiomyopathy. 8 (10.4%) were diagnosed with an inherited cardiac condition (n=2 HCM, n=1 DCM, n=5 LQTS). Another 7 (9.1%) are under surveillance because of a pathological ECG in the absence of a clinical phenotype.

The highest clinical yield was in the Long QT group (n=5, 55.6%). Family members (n=25) referred because of proband lateral TWI were the second most likely to require clinical follow-up because of a pathological ECG or a clinical diagnosis (n=7, 28.0%). Relatives referred because of isolated anterior TWI on the proband's ECG had the lowest diagnostic yield (n=17, 0%). After excluding families of probands with isolated anterior TWI (n=18), the overall clinical yield increased to 13.6%. Another 11.9% are under surveillance because of a pathological ECG.

Conclusion

The yield of family screening as part of a national cardiac screening program was 10.4%. This increases to 13.6% when excluding probands with anterior TWI, with 11.9% under surveillance because of a pathological ECG. To our knowledge, this is the first such study of its kind.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Beating Hearts MaltaResearch, Innovation and Development Trust (University of Malta)

Genetic variants as determinants of outcome in lamin A/C-related cardiac disease

Background

Current guidelines for the diagnosis and management of familial dilated cardiomyopathy highlight the variables “male sex” and “non-missense type variants” as risk factors for malignant ventricular arrhythmias.

Objective

Quantitative evaluation of prognostic differences between different LMNA variants associated with cardio-laminopathy.

Method

Analysis of cardiac event-free survival (sudden death, major arrhythmic events, death from heart failure and transplantation) with Kaplan-Meier approach in relation to gender & variant LMNA type. The data come from a specific database containing information on more than 1200 carriers of disease-causing LMNA variants. In the first analysis, the groups of comparison were truncating-type variants (LMNAtv) VS the global of pathogenic missense variants in the gene associated with cardiolaminopathy (LMNAm), segregated by gender. In the second analysis, it was considered missense LMNA affecting different residues (p.Arg190, p.Arg377 and p.Arg541), located in different functional domains, with enough data for comparison and with statistically different clinical behavior from that of global pathogenic variants in the gene. They were compared with the group of LMNAtv variants, as reference. The variants included were p.Arg377Cys/His, p.Arg541Cys/Ser/Gly/Pro/His and p.Arg190Trp/Gln/Pro, all of them pathogenic and associated with cardio-laminopathy.

Results

No significant differences were observed in survival between LMNAtv versus LMNAm variants (log rank=0.56) with slightly worse outcomes in males (log rank 0.03). Median survival time was 56 years for men compared to 60 years for women with LMNAtv, and 55 years compared to 66 years, respectively, among carriers of LMNAm (analysis A). In analysis B, statistically significant differences were observed between the groups considered (Log Rank p&lt;0.001). These differences were also clinically relevant (median survival time in groups p.Arg377, LMNAtv, p.Arg190 and p.Arg541 was 60, 58, 50 and 35 years, respectively). Importantly, more than 70% of the cardiac events observed were related to major ventricular arrhythmic episodes.

Conclusions

This quantitative analysis demonstrates that certain missense variants in LMNA may have a similar and even more adverse clinical course than the set of truncation-type variants. These findings highlight the relevance of the specific variant rather than the variant type in guiding actionable therapies to prevent adverse outcomes. Regarding the differences observed between genders, even though they are statistically significant, their magnitude could be clinically not relevant.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Health in Code

Alpha-protein kinase 3 (ALPK3) truncating variants cause an autosomal dominant form of hypertrophic cardiomyopathy

Background

More than half of hypertrophic cardiomyopathy (HCM) remains genetically unsolved. ALPK3 truncating variants (ALPK3tv) have been described as a cause of autosomal recessive cardiomyopathy in a small number of paediatric cases, but the pathogenicity in heterozygosity as a possible cause of autosomal dominant HCM is unknown.

Aims

To determine the frequency of heterozygous ALPK3tv in patients with HCM and to confirm their pathogenicity by means of burden testing in independent cohorts, family co-segregation studies, and functional analysis of an allelic series of ALPK3tv using human embryonic stem cell-cardiomyocytes (hESC-CM). Phenotype was compared with a cohort of 1679 genotyped HCM patients.

Methods and results

In a discovery cohort of 770 index patients with HCM, 12 (1.56%) were heterozygous for ALPK3tv, odds ratio (OR) 16.01 (95% confidence interval (95% CI): 7.89 to 29.74, p&lt;8.36e-11), compared to the Genome Aggregation Database (gnomAD) population. In a validation cohort of 2047 HCM probands, 32 (1.56%) carried heterozygous ALPK3tv, OR 16.17 (95% CI: 10.31 to 24.87; p&lt;2.2e-16, compared to gnomAD). Combined logarithm of odds score in 7 families with ALPK3tv was 2.99. In comparison with a large cohort of genotyped HCM patients, the phenotype of 51 HCM patients with ALPK3tv (probands and relatives) was characterised by a higher prevalence of apical/concentric patterns of hypertrophy (60%) compared to both sarcomere-positives or negatives (p&lt;0.001 overall), with the age at diagnosis (56±16ys) and maximum wall thickness (18±4mm) similar to sarcomere-negatives and LV systolic impairment at baseline (6%) and non-sustained ventricular tachycardia (31%) similar to sarcomere-positives. Short PR (10%, p=0.009 overall) and extensive fibrosis&gt;15% of LV segments (49%) were distinctive features. During follow-up (5.3±5.7 years), 4 (9%) patients died of heart failure or had cardiac transplantation (p=0.012 vs sarcomere-negatives and p=0.425 vs sarcomere-positives). Analysis of hESC-CM showed that ALPK3 heterozygotes had phenotypic characteristics of HCM, including increased contractile force and delayed membrane repolarization.

Conclusions

Heterozygous ALPK3tv are pathogenic and segregate with a characteristic HCM phenotype.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): MRC UK, UCLH BRC

Specific actin (ACTC1) missense variants are associated with different overlapping clinical phenotypes and outcomes

Introduction

Pathogenic variants in ACTC1 have been associated with hypertrophic (HCM), dilated (DCM), and left ventricular non-compaction (LVNC) cardiomyopathies. Phenotypes often overlap and atrial septal defects have also been reported. Prognostic data on carriers of these variants are scarce.

Methods and results

The proprietary database of a cardiovascular genetic laboratory was examined to assess penetrance and survival in the 438 carriers (191 families) of 75 missense variants in ACTC1 associated with disease. Their mean age at diagnosis was 32.4 (±18.7) years; 52% were male. The diagnosis was isolated HCM in 47%, LVNC in 17%, and DCM in 9%. LVNC with either HCM or DCM was present in an additional 8%; 13% had an atrial septal defect. Among carriers with echocardiographic information, left ventricular dilatation and dysfunction were described in 13% and 16%, respectively. Ventricular arrhythmias and conduction defects were reported in 94 and 93 carriers. Percentages have not been calculated for the latter, as we cannot ensure a denominator in whom cardiac conduction defects and arrhythmias were certainly discarded.

Overall, 50% of carriers were diagnosed by age 45, and 10% had experienced a major cardiac event. The p.Leu10Met and p.His90Tyr variants (23% of all carriers) demonstrated lower penetrance and a better prognosis than the p.Glu101Lys variant and the other missense variants.

Conclusions

Missense variants in ACTC1 are associated with a range of phenotypes that often overlap. Overall, penetrance and outcomes are age-dependent with a moderate rate of major cardiac events, which are highly dependent on the specific disease-causing variant

Funding Acknowledgement

Type of funding sources: None. Figure 1. The graph shows the percentage of carriers of pathogenic or likely pathogenic missense variants in the ACTC1 gene diagnosed at different ages. Considering all the missense variants in ACTC (in red), 50% of carriers had been diagnosed by age 45. It is worth highlighting the percentage of diagnosis (&gt;15%) in the first 15 years of life, which is higher than the figure usually observed in sarcomeric hypertrophic cardiomyopathy.Figure 2. The graph shows the survival free of major cardiovascular events (sudden, heart failure, stroke-related death, appropriate ICD therapy and heart transplant) in individuals with missense variants in ACTC1. Carriers and affected relatives without genetic study were included. Events were infrequent in two of the most informative variants (p.Leu10Met and p.His90Tyr), and significantly different compared with carriers of the other missense variants (p=0.036 for p.Leu10Met and p=0.015 for p.His90Tyr).

Narrowing of the neonatal region in the FBN1 gene

Background

Neonatal Marfan syndrome (MFS) is considered the most severe form of MFS and is characterized by early childhood death due to congestive heart failure. It has been suggested that genetic variants associated with this clinical presentation, cluster in a specific region between exons 24 and 32. It has been reported that patients carrying genetic variants in these exons have worse prognosis.

Purpose

Our purpose was to analyze cardiovascular outcome by location of the genetic variants in the “neonatal region” of the FBN1 gene.

Materials and methods

We analyzed clinical data on 1353 carriers and affected relatives with 683 missense pathogenic or likely pathogenic genetic variants of FBN1 gene (including cases identified in our laboratory and cases described in the literature) in whom age at last follow-up was available. Kaplan-Meier survival curves were generated to examine location of the genetic variant in the FBN1 gene in relation to survival free of surgical intervention or cardiovascular (CV) death (composite of deaths related to aortic dissection, heart failure/transplant, sudden, stroke or CV surgery).

Missense genetic variants were classified as located in the “neonatal region” (residues 952–1363, corresponding to exons 24–32) and in the “non-neonatal region” (residues 45–951 and 1364–2731). In the “neonatal region”, we have also analyzed a sub-region of “over-representation” of heart failure deaths in the first year of life, which we called “critical neonatal region” (amino acids 1028–1088, corresponding to exon 25 and few residues from exon 26) in comparison to the “non-critical neonatal region”.

Results

Data were examined on 1060 patients with missense variants located in the “non neonatal region” and on 293 patients with missense variants located in the “neonatal region”. Of these, 96 patients were carriers of missense variants in the “critical neonatal region”, the rest of patients carried variants in the neonatal region, outside this particular domain (“non-critical neonatal region”).

Patients carrying missense variants in the neonatal region had worse prognosis than those carrying variants outside this region. This poorer outcome was due to events occurring in patients carrying variants in the “critical neonatal region” (see Figure). These patients had the worse prognosis (p=0.000108, vs. the other groups). Furthermore, events in the non-critical neonatal region were similar to other missense variants located outside the neonatal region.

There were no differences in the “neonatal region” when analyzing by gender.

Conclusion

In our cohort, the worse prognosis seen in patients carrying missense pathogenic or likely pathogenic variants in the “neonatal region” compared to the “non-neonatal region”, was due to events in patients carrying missense variants in a small subregion which we called the “critical-neonatal region” (exons 25 and 26). These patients had the worse prognosis, irrespective of gender.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Health in Code Figure 1. Neonatal region FBN1

Molecular characterization of a cohort of individuals referred to genetic testing with suspected CPVT

Background

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is one of the most lethal inherited arrhythmogenic diseases and it mainly affects the young, in the absence of structural heart disease. This condition is difficult to diagnose and the first expression of disease can be an arrhythmic death. In the last years, genetic testing has become a useful tool in the challenging task of CPVT diagnosis.

The diagnostic yield of the genetic study is highly variable and dependent on the phenotypic characteristics of the individuals evaluated.

Purpose

This study aimed to address the clinical characteristics and genetic testing (GT) results in a cohort of individuals referred to genetic analysis with a non-definitive diagnosis of CPVT, in a real world-setting.

Methods

This is a retrospective cohort study of patients referred for GT with clinical suspicion of CPVT, but who did not strictly meet the diagnostic criteria for this disease (according to current guidelines). NGS genotyping was performed with a library of 251 genes. NGS-based genomic testing was performed with classification of identified variants according to American College of Medical Genetics and Genomics guidelines.

Results

One hundred and sixteen unrelated patients with available clinical information (patients' characteristics are summarized in TABLE1) were included in the analysis. Mean age at GT was 36 y/o (±19), 47% were women and 18% had a familial history of sudden cardiac death.

The first clinical manifestation was: exercise or stress induced syncope in 36%, exercise induced ventricular tachycardia in 30% and sudden cardiac arrest in 15.5% (78% during emotional or physical stress - 89% aborted sudden death). Mean age at sudden death was 20 y/o (±14).

GT was positive in 49.1% (n=57), negative in 37.9% (n=44) and inconclusive in 12.9% (n=15). We had identified pathogenic/likely pathogenic variants in CPVT-related genes in 40% of the referred patients: RYR2 (70.2%-n: 40), KCNJ2 (8.8%-n: 5), CASQ2 in homozygous/compound heterozygous carriers (3.5%-n: 2). In the RYR2 gene we detected 36 different genetic variants (13 were novel) in 40 different individuals. In addition, relevant variants were also identified in other genes associated with channelopathies (SCN5A, 3.5%, n: 2 and KCNQ1, 1.7%, n: 1) and in genes associated with structural heart disease: desmosomal genes (6.8%-DSP n: 1 and PKP2 n: 3) and sarcomeric genes (5.1%- MYBPC3 and MYH7) (figure 1A-B).

Conclusions

In our cohort of patients with non-definitive diagnosis of CPVT, the diagnostic yield of genetic testing was almost 50%. GT allowed confirmation of the suspicion of CPVT in 40% of the patients and, in addition, we were able to detect relevant genetic variants in other genes not associated with CPVT in 10% (differential diagnosis). The use of wide genetic panels would be useful in this context.

Funding Acknowledgement

Type of funding sources: None. Suspected CPVT. Genetic Testing.

Marfan syndrome: genetic variant determinants of cardiovascular outcomes

Background

Marfan syndrome is a systemic connective tissue disorder caused by genetic variants in the fibrillin-1 (FBN1) gene. Cardiovascular complications are the leading cause of mortality.

Purpose

To compare cardiovascular outcome by gender and by type of the genetic variant in the FBN1 gene.

Materials and methods

We analyzed clinical data on 1956 carriers and affected relatives with 1430 pathogenic or likely pathogenic genetic variants in the FBN1 gene (including cases identified in our laboratory and cases described in the literature) in whom age at last follow-up was available. We excluded patients with pathogenic or likely pathogenic genetic variants located in the so-called “neonatal region” (exon 24–32); they are recognized to have an early onset/severe phenotype.

Kaplan-Meier survival curves were generated to examine gender and type of genetic variant in relation to survival free of surgical intervention or cardiovascular (CV) death (composite of deaths related to aortic dissection, heart failure/transplant, sudden, stroke or CV surgery). Genetic variants were classified as truncating (nonsense, frameshift and splicing), “missense non-neonatal” and only those missense eliminating a Cysteine residue in the non-neonatal region (“Cys non-neonatal”).

Results

Data were examined on 896 patients with truncating variants (53% male; 47% female) and 1060 with missense variants, located outside the “neonatal region” (54% male; 46% female). Of these, 475 were missense variants substituting a cysteine residue (52% male; 48% female).

Those with truncating variants had worse prognosis versus those with missense and Cys variants (p=0.000108 and p=0.000115), with earlier onset of cardiovascular events. Overall, patients with missense variants had similar prognosis to those with missense variants eliminating a Cysteine residue. By age 65, however, almost 50% of patients with any type of variant had suffered a CV event, and with each variant type males had worse prognosis (see Figure 1). This was most evident in males aged 30 to 50 with missense variants that substituted a Cysteine residue, while female carriers of these variants had a prognosis similar to other missense variants (see Figure 2).

During the first decade carriers of missense and truncating variants mainly died of heart failure. From age 10 to 50, aortic dissection was the most common event, while later other events became more frequent, e.g. vascular intervention and sudden death.

Conclusion

In our cohort, male carriers of pathogenic or likely pathogenic variants had worse prognosis versus females. Carriers of truncating variants had the worst CV outcomes. However, it is noteworthy that by age 65, regardless of gender or mutation type, close to 50% of patients had experienced a major CV event/death.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Health in Code Figure 2. Type by gender

Prognostic value of reduced heart rate reserve during exercise stress-echocardiography in hypertrophic cardiomyopathy

Background

Heart rate reserve (HRR) during exercise evaluates chronotropic incompetence and is a prognostically important marker of cardiac autonomic dysfunction, additive to regional wall motion abnormalities (RWMA) in patients with coronary artery disease.

Objectives

To assess determinants and prognostic value of HRR in patients with hypertrophic cardiomyopathy (HCM).

Methods

From 1998 to 2019, we enrolled 774 HCM patients (age = 48.8±15.9 years, 410 men) with exercise stress echocardiography (ESE) in 10 certified centres of the international stress echo network. During ESE we assessed: left ventricular outflow tract obstruction (LVOTO, significant when &gt;50 mmHg); RWMA; HRR (peak/ rest heart rate), 344 in beta-blockers therapy (44.4%). Patients were followed for a median 49 months (IQ range, 25–78 months). The study end-point was all-cause mortality.

Results

During ESE, we observed stress-induced RWMA in 42 (5.4%) and LVOTO in 248 (33%); HRR was 1.92.±0.41. There were no difference in patients with normal and abnormal HRR with and without beta-blockers therapy (147, 41.1% vs 211, 58.9%, p=0.079). During follow-up, 43 deaths occurred. Beta blockers therapy in univariate analysis did not have prognostic role (HR 1.105, 95% CI 0.602–2.028, p=0.768). The lowest HRR quartile (≤1.62) had a 10-fold higher 6-year death rate (10.9%) than the highest quartile (&gt;2.16, 1.04%): see figure. At multivariable analysis, lowest HRR quartile (HR 2.074, 95% CI 1.082–6.773, p=0.034), age (HR 1.045, 95% CI 1.014–1.077, p=0.004), maximal wall thickness (HR 1.137, 95% CI 1.054–1.226, p=0.001), stress-induced RWMA s(HR 4.289, 95% CI 1.733–10.615, p=0.002) and ≥ moderate mitral regurgitation at rest (HR 3.127, 95% CI 1.507–6.488, p=0.002) predicted death.

Conclusions

A blunted HRR during ESE predicts adverse outcome independent of inducible RWMA in HCM patients. Autonomic dysfunction deserves consideration as a potential therapeutic target in this disease.

Figure 1

Funding Acknowledgement

Type of funding source: None

Gender variability in the clinical phenotype of hypertrophic cardiomyopathy

Introduction

Hypertrophic cardiomyopathy (HCM) is a structural heart disease defined by an increase in left-ventricular (LV) wall thickness, that may be complicated with a clinical syndrome of heart failure, arrhythmia and death.

Purpose

To characterize the clinically significant factors for female HCM patients and bring forward the awareness to gender-based differences in HCM.

Methods

We reviewed the patient records of 1297 patients age ≥18 years, diagnosed with HCM, from two tertiary medical centers in Spain and Israel, and analyzed 748 male and female patients matched for age ≥60 years at admission, BMI, hypertension, diabetes and obstructive HCM.

Results

Female patients were older at original diagnosis [median 54 years (38–66) vs. 50 years (35–60), p=0.007], and had higher rates of family history of both HCM (46% vs. 37%, p=0.01) and sudden cardiac death (23% vs. 15%, p=0.02). Female patients had lower rates of active smoking (11% vs. 25%, p&lt;0.001) and coronary disease (3% vs. 8%, p=0.007). In echocardiographic studies, females had a smaller LV cavity both during diastole [median 42mm (39–46) vs. 46 (42–50), p&lt;0.001] and during systole [median 24 (21–29) vs. 27 (23–31), p&lt;0.001]. Female patients had higher rates of significant mitral insufficiency (37% vs. 19%, p&lt;0.001), and despite no significant differences in the rates of obstructive HCM, diastolic dysfunction, left-atrial enlargement, atrial fibrillation, ventricular tachyarrhythmia or pulmonary disease, they also had more significant pulmonary hypertension (≥45mmHg, 29% vs. 14%, p&lt;0.001). Women had a lower functional capacity (p&lt;0.001 for differences in NYHA, see fig.), and lower exercise capacity [median 7.0 METs (5–10) vs. 10.0 (7–12), p&lt;0.001) and more abnormal blood pressure response to exercise (35% vs. 26%, p=0.03). Electrocardiographic features were similar across genders, except for a non-clinically significant shorter QRS duration in females. No significant differences were seen in 5-year mortality follow-up, which was ∼3% in the entire cohort.

Conclusions

Female patients suffering from HCM have a clinical phenotype defined by slightly later presentation (and shorter time until admission to a tertiary-center cardiomyopathy clinic), smaller LV cavity size, higher severity of mitral insufficiency and pulmonary hypertension and worse functional and exercise capacities. Genders did not differ in 5-year mortality, which was relatively low.

Functional and exercise capacity

Funding Acknowledgement

Type of funding source: None

Genotype/Phenotype correlation and prognosis for undescribed ACTC1 missense variants

Purpose

Establish the genotype/phenotype correlation for missense undescribed variants in ACTC1, and evaluate their prognostic implications.

Methods

A systematic screening for the ACTC1 gene was performed using NGS in 17,683 individuals with inherited cardiovascular disease, 6,984 of them with hypertrophic cardiomyopathy, 3,507 with dilated cardiomyopathy, and 760 left ventricular non-compaction. These phenotypes were clinically diagnosed by each center prior to the genetic study. Frequency of the variants was compared with gene gnomAD and ClinVar databases. A systematic review of the literature was performed to search for previously reported variants.

We evaluated available follow up data and constructed Kaplan-Meier survival curves free from cardiovascular death (sudden death, Heart transplant, heart failure death, appropriate ICD discharge and stroke related death). Log-rank test was used to compare event-free survival time between males and females.

Results

39 missense variants were identified in 283 carriers (125 index cases; 158 first-degree relatives). Twenty-two have not been previously described or identified in public databases. 17 have been reported in gnomAD or Clinvar. Carriers phenotypes were: 120 HCM; 43 LVNC; 16 DCM; three had cardiac septal defect and two had sudden death. Some of the carriers had overlapped or combined phenotypes: 7 HCM and LVNC, 7 septal defects and LVNC, 3 HCM and septal defects, 4 MCD and LVNC. 24 were healthy carriers, and we have no phenotypic data of the remaining individuals. Family studies were performed in 12 families out of the 22 undescribed variants, showing cosegregation in 8 variants. One case was “de novo”.

Interestingly, a rare variant, previously identified as VUS in ClinVar, showed a clearly cosegregation with HCM. The Leu10Met variant with a frequency of 9/282084 alleles in gnomAD (1/15671 individuals) was identified in 20 index cases, which represents 1/884 of all the genotyped (0.11%), and 1/387 patients with HCM (0.35%). We found it in 2/9289 patients with other phenotypes (p&lt;0.001).

51 patients (18%) presented an event during follow up. In several cases, carriers developed early atrial fibrillation.

The survival curve shows adverse events from the first decade of life, with a 10% cumulative rate of events at age 40, 80% survival at age 60, and a 60% survival at age 70. No significant differences in the incidence of cardiovascular death between men and women were observed.

Conclusion

HCM is the most frequent phenotype in carriers of ACTC1 variants, followed by LVNC, and DCM. Septal defects are not rare, and they are usually described in combination with cardiomyopathies.

Disease course seems to have a good prognosis. Sudden death is an exception at early ages and appears to be associated with severe morphological expression.

Given the presence of cosegregation with disease in rare variants, many of the ACTC1 variants may have an incomplete penetrance, and late disease expression.

ACTC1

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Health in Code

Novel Filamin C missense mutation associated with severe restrictive cardiomyopathy overlapping with left ventricular non-compaction

Introduction

Filamin C gene (FLNC) missense mutations have been previously reported in association with restrictive cardiomyopathy (RCM). The association of FLNC missense variants with non-compaction cardiomyopathy has been reported only in a single proband, but familiar or functional evidence on its causative effect is limited. Overlapping traits among cardiomyopathies related to the same genetic substrate is an emerging and a challenging scenario nowadays.

Purpose

To report a new pathogenic FLNC missense variant in association with a particular form of restrictive/non-compaction overlapping cardiomyopathy.

Methods

The probands fulfill the diagnostic criteria for RCM based on current guidelines. Genetic testing in the probands was performed by NGS, using a broad gene panel (containing over 240 genes). Clinical and genetic cascade screening were expanded to first-degree relatives when it was possible. All mutation carriers underwent clinical assessment including physical examination, 12-lead ECG, echocardiography, cardiac magnetic resonance (MRI), 24h Holter monitoring, and ergometry. None of them had major systemic illnesses nor clinical symptoms of muscular involvement.

Results

The p.Gly2011Arg variant in the FLNC gene was the only relevant variant in the three probands. This variant is virtually absent in the general population (gnomAD). The variant showed a de novo presentation in the first family and segregated with the phenotype in the four studied relatives from the second family (three affected carriers and one unaffected non-carrier). In the third case no familial information was available. This variant affects an ultraconserved residue and is located in a relevant sub-region of Filamin-C, which is necessary for its interaction with other Z-disc proteins. Detailed clinical information is available on all carriers (n=5, 1 male). The average age at diagnosis is 17 years [1–36]. An abnormal ECG was the earliest clinical manifestation (left ventricular hypertrophy by voltage criteria and extensive repolarization abnormalities). Significant hypertrabeculations, mainly at the anterolateral wall and basal anteroseptal segments, was present in all affected carriers. Interestingly, none of them showed an abnormal late-gadolinium enhancement pattern on MRI. The four carriers who were older than 35 years were found to have severe restrictive pattern on echocardiography (functional parameters and secondary features such as bi-atrial dilation), all four suffered from limiting dyspnea, and two are under pre-transplant workup (A-II-1 and B-III-1). One of them had a cardioembolic event (femoral acute ischemia, A-II-1). One relative has recently died from advanced heart failure (B-II-2).

Conclusion

This is the first description on this overlapping (restrictive/non-compaction cardiomyopathy) and aggressive phenotype associated with a missense FLNC variant. This description widens the clinical spectrum related to FLNC missense mutations.

Pedigrees and clinical characterization

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Health in Code

Value of a comprehensive exercise echocardiography assessment for patients with hypertrophic cardiomyopathy

Background

Exercise echocardiography (ExE) may assess left ventricular (LV) systolic and diastolic function, LV outflow tract (LVOT) obstruction and mitral regurgitation (MR). We aimed to assess the feasibility and prognostic value of the assessment of all these issues during exercise in patients with hypertrophic cardiomyopathy (HCM).

Methods

LV systolic and diastolic function, LVOT gradients, and MR were evaluated during ExE in 285 patients with HCM (age 60±14 years, 168 men) and preserved LVEF (≥50%). Recordings were obtained at rest and peak exercise for regional/global LV systolic function and at rest and within 1.5 min after exercise for the rest of assessments: LVOT gradients, MR and ratio of early LV inflow velocity to early tissue Doppler septal annulus velocity (E/e').

Results

Feasibility was 100%, 97%, 98% and 98% for LV systolic function, E/e', LVOT gradients, and MR assessments at exercise, respectively. Thirty-seven patients (13%) had LVOT obstruction at rest, and 76 (27%) developed exercise-induced LVOT obstruction. Mean resting LVEF was 63±3%. New wall motion abnormalities (WMAs) were detected in 38 patients (13%). E/e'&gt;15 was observed in 108 patients at rest (38%) and in 119 at exercise (42%). Corresponding figures for significant MR (moderate or severe) were 20 (7%) and 17 (6%). During follow-up of 3.9±2.5 years, 21 patients had a hard event (cardiac death or transplantation, appropriate discharge of a defibrillator, stroke, myocardial infarction, hospitalization for heart failure), 33 a combined event (hard plus new atrial fibrillation or syncope), and 53 a combined event plus any interventionism.

After adjustment, LV wall thickness, resting LVEF, maximal workload in Metabolic Equivalents (METs), and E/e' post-exercise resulted independent predictors of hard events (HR=1.45, 95% CI: 1.21–1.74, p&lt;0.001; HR=0.80, CI: 0.71–0.89, p&lt;0.001; HR=0.73, 95% CI: 0.62–0.86, p&lt;0.001; HR=1.08, 95% CI: 1.02–1.14, p&lt;0.009, respectively). Independent predictors of combined events included also LV wall thickness, resting LVEF, and METs, along with therapy with beta-blockers at the time of ExE (HR=1.29, 95% CI: 1.12–1.50, p=0.001; HR=0.89, CI: 0.81–0.97, p=0.012; HR=0.83, 95% CI: 0.74–0.93, p=0.001; HR=2.51, 95% CI: 1.20–5.25, p=0.015), whereas the model for combined events+any interventionism consisted of beta-blockers, LV wall thickness, LA dimension, METs and new WMAs. (HR=2.15, 95% CI: 1.20–3.86, p=0.01; HR=1.17, 95% CI: 1.03–1.32, p=0.02; HR=1.07, CI: 1.02–1.11, p=0.005; HR=0.90, 95% CI: 0.82–0.98, p=0.01; HR=2.33, 95% CI: 1.17–4.63, p=0.016)

Conclusions

A comprehensive assessment during ExE is feasible for patients with HCM and provides significant incremental prognostic information

Funding Acknowledgement

Type of funding source: None

Effect of hypokintic transformation on the clinical phenotype and functional capacity in hypertrophic cardiomyopathy

Background

Advanced hypertrophic cardiomyopathy (HCM) may be complicated by a dilated hypokinetic transformation. Reduced left ventricular ejection fraction (HFrEF) has been described in terms of specific risks of morbidity and mortality, and specifically in terms of increased risk for fatal arrhythmias. Nevertheless, recent publications have casted doubt regarding the role of arrhythmia in non-ischemic HFrEF and questioned the role of primary prevention strategies in these cases.

Methods

We've reviewed clinical characteristics of 883 patients age ≥40, diagnosed with HCM who were evaluated in the cardiomyopathy clinic in two tertiary medical centers in Israel and Spain.

Results

Forty-five patients (5%) suffered from hypokinetic transformation. They were younger at diagnosis (median 32 [IQR 24–55] vs. 49 [35–60], p&lt;0.001), had a lower body-mass index (28.4 [±4.7] vs. 26.0 [±3.9], p&lt;0.001), and suffered more from strokes (19% vs 6%, p&lt;0.001). They had lower had a lower NYHA class (p=0.001) and lower exercise capacity (7.3 [4.5–10.8] vs. 9.6 [6.7–12.0] METS, p&lt;0.001). Patients with hypokinetic HCM had higher rates of pacemaker and implanted defibrillator (ICD) implantations (41% vs 11%, p&lt;0.001) and (43% vs 13%, p&lt;0.001) respectively. These patients had a higher incidence of sustained ventricular tachyarrhythmias (14% vs 2%, p&lt;0.001). Among patients who had an ICD, patients suffering from hypokinetic transformation had received more appropriate ICD therapy (27% vs 12%, p&lt;0.001). These patients received more heart transplantations (13% vs 1%, p&lt;0.001), and had a trend for higher incidence rate of Sudden cardiac death (6% vs 2% p=0.06) and a higher 5-year mortality rates (21% vs. 5%, p&lt;0.001).

Conclusions

HCM patients suffering from hypokinetic transformation have lower functional and exercise capacities, are more likely to suffer from ventricular tachyarrhythmias and experience appropriate ICD therapy, and undergo heart transplantation. They also have a significantly lower 5-year survival.

Five-year survival

Funding Acknowledgement

Type of funding source: None

Genetic Alterations in the PI3K/AKT Pathway and Baseline AKT Activity Define AKT Inhibitor Sensitivity in Breast Cancer Patient-derived Xenografts

PURPOSE

AZD5363/capivasertib is a pan-AKT catalytic inhibitor with promising activity in combination with paclitaxel in triple-negative metastatic breast cancer harboring PI3K/AKT-pathway alterations and in estrogen receptor-positive breast cancer in combination with fulvestrant. Here, we aimed to identify response biomarkers and uncover mechanisms of resistance to AZD5363 and its combination with paclitaxel.

EXPERIMENTAL DESIGN

Genetic and proteomic markers were analyzed in 28 HER2-negative patient-derived xenografts (PDXs) and in patient samples, and correlated to AZD5363 sensitivity as single agent and in combination with paclitaxel.

RESULTS

Four PDX were derived from patients receiving AZD5363 in the clinic which exhibited concordant treatment response. Mutations in PIK3CA/AKT1 and absence of mTOR complex 1 (mTORC1)-activating alterations, for example, in MTOR or TSC1, were associated with sensitivity to AZD5363 monotherapy. Interestingly, excluding PTEN from the composite biomarker increased its accuracy from 64% to 89%. Moreover, resistant PDXs exhibited low baseline pAKT S473 and residual pS6 S235 upon treatment, suggesting that parallel pathways bypass AKT/S6K1 signaling in these models. We identified two mechanisms of acquired resistance to AZD5363: cyclin D1 overexpression and loss of AKT1 p.E17K.

CONCLUSIONS

This study provides insight into putative predictive biomarkers of response and acquired resistance to AZD5363 in HER2-negative metastatic breast cancer.

P3688Familial recurrent autoimmune myocarditis associated with a truncating nonsense mutation of the desmoplakin gene

Background

Arrhythmogenic cardiomyopathy (AC) is an important cause of ventricular arrhythmias in children and young adults. AC is associated with mutation of desmosomal proteins, however, cardiac disease penetrance is incomplete and the clinical course varies widely without recognizable exogenous or epi/genetic co-factors. Importantly, DSP mutation carriers may also display entirely non-cardiac e.g. dermatological phenotypes.

Methods and results

In two brothers with recurrent fulminant myocarditis, mutation screening of 218 cardiomyopathy-related genes identified a truncating mutation Arg1458* of desmoplakin (DSP). DSP immunhistology unexpectedly revealed complete loss (“knockout”) of DSP protein in endomyocardial biopsies (EMBs), but none of the histological anomalies of AC. Criteria for histological diagnosis of myocarditis were not either fulfilled, and cardiac MRI revealed no features associated with AC. Screening for infections was negative, there was no substance abuse, medication or vaccination. Possible disease triggers were competitive sport events. Myosin and troponin I autoantibodies were detected at titers up to 1:320.

We used allele-specific RT-PCR to distinguish if the patients' allele classified as “normal” was actually defective due to promotor mutation or epigenetic silencing. RT-PCRs were done on EMBs and peripheral blood mononuclear cells (PBMCs). In a cohort of dilated cardiomyopathy (DCM) patients we were able to detect DSP transcripts in both, PBMC and left-ventricular heart tissue. RNA sequencing of human PBMC subpopulations suggested that DSP transcription may be restricted to certain immune cell subtypes. RT-PCRs revealed that both Arg1458* carriers have a functional second DSP allele, indicating that their “DSP knockout” occurs at the protein level and may be due to protein instability and degradation within desmosomes.

We screened additional existing cohorts for such variants and identified stopgain variant Gln307Ter in a 37-yrs-old woman with ARVC. This patient's sister died from heart failure at the age of 39. In a 59-yrs-old female LVNC patient, stopgain variant Y1391X was identified. Here, family history was unclear, her brother probably died from coronary artery disease. In a 71-yrs-old female DCM patient with no family history, stopgain variant Tyr1512Ter was identified.

Conclusions

The described patients with DSP truncations strongly suggest the existence of additional genetic or exogenous modifiers driving pathogenesis either way. DSP defects may cause recurrent myocarditis, and mutation screening is advisable to enable early detection of high-risk patients with similar phenotypes. Our finding of complete myocardial DSP protein loss emphasizes that DNA sequencing may miss critical molecular disturbances. It is indispensable to also analyze transcriptome and protein level in the tissue actually affected in a patient in order to recognize his/her individual pathogenesis.

Computerized registry of patients with hemorrhagic hereditary telangiectasia (RiHHTa Registry) in Spain: Objectives, methods, and preliminary results

INTRODUCTION

Hereditary hemorrhagic telangiectasia (HHT) is a rare disease with autosomal dominant inheritance that causes systemic vascular affectation.

MATERIAL AND METHOD

After development a multicentric Spanish national registry, called RiHHTa, main clinical manifestations and diagnostic procedures of the first patients introduced are described.

RESULTS

141 patients were included, of which 91 (64.5%) were women. The mean age at diagnosis was 42 years. Mutations in the ACVRL1 gene predominated over the ENG gene. The initial symptom was recurrent epistaxis in 130 (92.2%) patients and in three (2.1%), brain abscess. Pulmonary arteriovenous (AV) fistula were detected in 36 (45%) of the 79 patients who underwent thoracic CT angiography. The contrast echocardiography detected very few bubbles (grade I) or none, in 36 (45%) of these 79 affected patients. In 43 (67.2%) of the 64 patients with an abdominal CT angiography, hepatic vascular malformations were detected, mostly telangiectasias, AV and arterio-portal fistula, and extrahepatic in 14 (10%) subjects. More than half of the patients were screened for the presence of brain arteriovenous malformations which was found in 3.9% of them. The upper part of the intestinal tube was the most (95%) affected region.

CONCLUSION

The RiHHTa Registry allows improving the management of patients with HHT. An inadequate use of thoracic CT angiography and the usefulness of abdominal CT angiography has been detected in order to define subtypes of hepatic vascular involvement and detect extrahepatic vascular involvement.

Corrigendum: Effect of age on pro-inflammatory miRNAs contained in mesenchymal stem cell-derived extracellular vesicles

This corrects the article DOI: 10.1038/srep43923.

Effect of age on pro-inflammatory miRNAs contained in mesenchymal stem cell-derived extracellular vesicles

Stem cells possess significant age-dependent differences in their immune-response profile. These differences were analysed by Next-Generation Sequencing of six age groups from bone marrow mesenchymal stem cells. A total of 9,628 genes presenting differential expression between age groups were grouped into metabolic pathways. We focused our research on young, pre-pubertal and adult groups, which presented the highest amount of differentially expressed genes related to inflammation mediated by chemokine and cytokine signalling pathways compared with the newborn group, which was used as a control. Extracellular vesicles extracted from each group were characterized by nanoparticle tracking and flow cytometry analysis, and several micro-RNAs were verified by quantitative real-time polymerase chain reaction because of their relationship with the pathway of interest. Since miR-21-5p showed the highest statistically significant expression in extracellular vesicles from mesenchymal stem cells of the pre-pubertal group, we conducted a functional experiment inhibiting its expression and investigating the modulation of Toll-Like Receptor 4 and their link to damage-associated molecular patterns. Together, these results indicate for the first time that mesenchymal stem cell-derived extracellular vesicles have significant age-dependent differences in their immune profiles.

WITHDRAWN: Accuracy of Peak Treadmill Exercise Echocardiography to Detect Multivessel Coronary Artery Disease: Comparison with Post-exercise Echocardiography

The publisher regrets that this was an accidental duplication of an article that has already been published in Eur. J. Echocardiogr., 4 (2003) 182-190, . The duplicate article has therefore been withdrawn.

Accuracy of peak treadmill exercise echocardiography to detect multivessel coronary artery disease: comparison with post-exercise echocardiography

AIMS

Although peak exercise echocardiography has been reported for both bicycle and treadmill exercise and has shown higher sensitivity than post-exercise imaging, little is known about its utility for identifying multivessel involvement. We sought to compare feasibility and accuracy of peak treadmill exercise echocardiography vs post-exercise echocardiography for identification of multivessel coronary artery disease and to assess its incremental value when combined with clinical and exercise test variables.

METHODS AND RESULTS

The study group included 335 patients (228 men; mean (+/- SD) age 60 +/- 11 years). Two hundred and seventy-nine patients were included on the basis of having had an exercise echocardiography and a coronary angiography within 4 months of the exercise test. To avoid bias to coronary angiography, a subgroup of 56 consecutive non-diabetic patients referred for exercise echocardiography with pretest probability of coronary artery disease <10% and had atypical chest pain or were asymptomatic were also included and considered as having no coronary artery disease. Multivessel coronary artery disease (> or = 50% diameter stenosis in >1 vessel) was confirmed in 170 patients, whereas 165 patients were considered to have one-vessel coronary artery disease or no coronary lesions. Positive exercise echocardiography was defined as ischaemia or necrosis in at least two coronary territories. Post-exercise images were acquired within 125 s after exercise (49 +/- 15). Mean heart rate (bpm) was 139 +/- 19 at peak vs 117 +/- 22 at post-exercise imaging (P<0.001). Interpretable peak and post-exercise images were obtained for all patients. Sensitivity for predicting multivessel disease was higher with peak than with post-exercise imaging (79 vs 55%, P<0.001), with lower specificity (79 vs 88%, P<0.05). Predictive positive value was similar (80 vs 83%). Negative predictive value was again higher with peak imaging (78 vs 66%, P<0.01). Total accuracy was not different (79 vs 72%). A stepwise logistic regression analysis identified peak exercise echocardiography positivity for multivessel coronary artery disease as the strongest independent predictor of multivessel disease (odds ratio (OR): 7.36); also significant were male gender (OR: 4.22), diabetes mellitus (OR: 4.28), previous myocardial infarction (OR: 3.12) and increment of product heart rate x blood pressure (OR: 1.00).

CONCLUSIONS

Peak treadmill exercise echocardiography is technically feasible and has higher sensitivity and negative predictive value for predicting multivessel disease than post-treadmill exercise echocardiography. This method adds independent and incremental values to clinical and exercise variables for the diagnosis of multivessel coronary artery disease. Therefore, in the clinical setting, peak exercise echocardiography should be performed to diagnose multivessel coronary artery disease.

Comparison of two-dimensional echocardiography and pulsed Doppler tissue imaging during dobutamine-atropine stress testing to detect coronary artery disease

In order to compare the diagnostic accuracy of two-dimensional (2-D) echocardiography and pulsed Doppler tissue imaging (pDTI) during dobutamine-atropine stress testing (DAST) to detect significant coronary lesions, 41 patients underwent DAST (up to 40 microg/k/min of dobutamine with additional atropine during submaximal heart rate responses) and coronary angiography. Pulsed Doppler tissue sampling of territories corresponding to the left anterior descending (LAD), left circumflex (LCx), and right coronary arteries (RCAs) were performed in the apical four-chamber plus aorta and two-chamber apical views. The measurements were repeated at rest, at low dose (10 microg/k/min), and at peak stress. Pulsed DTI measurements included peak early systolic (Vs), peak early diastolic (Ve), and peak late diastolic (Va) velocities. Harmonic 2-D echocardiography was recorded at rest, low dose, peak stress, and recovery, and compared with pDTI assessment. Positive 2-D echocardiography was considered as infarction or ischemic response. The results were evaluated for the prediction of significant coronary stenosis (50% luminal narrowing). Feasibility of pDTI was 100%, 95%, and 98% for the LAD, the LCx, and RCA territories, respectively. At rest, Vs in territories supplied by arteries with coronary artery disease (CAD) (6.3 +/- 2.0 cm/sec) was not different from those without (6.6 +/- 2.1 cm/sec). Vs increased less in territories supplied by arteries with than without CAD (75 +/- 107% vs 102 +/- 69%, P = NS). Ve was lower in territories with CAD at rest (6.0 +/- 2.1 cm/sec vs 8.2 +/- 3.4 cm/sec, P < 0.0001) and low dose (7.2 +/- 2.1 cm/sec vs 8.8 +/- 3.6 cm/sec, P < 0.01), but similar at peak stress (7.6 +/- 3.5 cm/sec vs 8.1 +/- 3.3 cm/sec). Ve increase was similar in territories with (36 +/- 74%) than without CAD (15 +/- 6 4%). Va was similar at rest and low dose in territories with and without CAD (9.2 +/- 2.7 cm/sec vs 9.1 +/- 2.3 cm/sec and 10.9 +/- 3.1 vs 10.3 +/- 3.6 cm/sec, respectively), but lower at peak stress in territories with CAD (13.3 +/- 4.6 cm/sec vs 15.3 +/- 4.5 cm/sec, P = 0.05). The Va increase was lower in territories with CAD (43 +/- 37% vs 77 +/- 72%, P < 0.05). In a territory-based analysis, a failure to achieve Vs > or =10.5 cm/sec at peak stress in the LAD and LCx, and > or =10.0 cm/sec in the RCA territory, was found to be the more accurate limit to detect CAD in the corresponding arteries: sensitivity (95% confidence intervals): 63% (55-71), P = NS vs 2-D echocardiography: 59% (51-67); specificity 76% (68-84), P < 0.01 vs. 2-D echocardiography: 95% (89-100); and accuracy 69% (63-75), P = NS vs 2-D echocardiography: 76% (70-82). Thus, pDTI is feasible during DAST but not more accurate than 2-D echocardiography for the detection of significant CAD in a territory-based study.

Sudden death in hypertrophic cardiomyopathy: identification of high risk patients

OBJECTIVES

We sought to identify patients with hypertrophic cardiomyopathy (HCM) at high risk of sudden death (SD).

BACKGROUND

Relatively low mortality rates in HCM make conventional analysis of multiple clinical risk markers for SD problematic. This study used a referral center registry to investigate a smaller number of generally accepted noninvasive risk markers.

METHODS

We studied 368 patients (14 to 65 years old, 239 males) with HCM. There were five variables: nonsustained ventricular tachycardia (NSVT), syncope, exercise blood pressure response (BPR), family history of sudden death (FHSD) and left ventricular wall thickness (LVWT).

RESULTS

During follow-up (3.6+/-2.5 years [range 2 days to 9.6 years]), 36 patients (9.8%) died, 22 of them suddenly. Two patients received heart transplants. The six-year SD-free survival rate was 91% (95% confidence interval [CI] 87% to 95%). In the Cox model, there was a significant pairwise interaction between FHSD and syncope (p = 0.01), and these were subsequently considered together. The multivariate SD risk ratios (with 95% CIs) were 1.8 for BPR (0.7 to 4.4) (p = 0.22); 5.3 for FHSD and syncope (1.9 to 14.9) (p = 0.002); 1.9 for NSVT (0.7 to 5.0) (p = 0.18) and 2.9 for LVWT (1.1 to 7.1) (p = 0.03). Patients with no risk factors (n = 203) had an estimated six-year SD-free survival rate of 95% (95% CI 91% to 99%). The corresponding six-year estimates (with 95% CIs) for one (n = 122), two (n = 36) and three (n = 7) risk factors were 93% (87% to 99%), 82% (67% to 96%) and 36% (0% to 75%), respectively. Patients with two or more risk factors had a lower six-year SD survival rate (95% CI) compared with patients with one or no risk factors (72% [56% to 88%] vs. 94% [91% to 98%]) (p = 0.0001).

CONCLUSIONS

This study demonstrates that patients with multiple risk factors have a substantially increased risk of SD sufficient to warrant consideration for prophylactic therapy.

Accuracy of exercise echocardiography to detect coronary artery disease in left bundle branch block unassociated with either acute or healed myocardial infarction

To search for the value of treadmill exercise echocardiography in the detection of coronary artery disease in noninfarcted patients with left bundle branch block, we studied 35 patients (17 with coronary artery disease). We found high sensitivity, specificity, and accuracy (76%, 83%, and 80%, respectively).