Genotype-phenotype correlations in hypertrophic cardiomyopathy: a multicenter study in Portugal and Spain of the TPM1 p.Arg21Leu variant.

INTRODUCTION AND OBJECTIVES: TPM1 is one of the main hypertrophic cardiomyopathy (HCM) genes. Clinical information on carriers is relatively scarce, limiting the interpretation of genetic findings in individual patients. Our aim was to establish genotype-phenotype correlations of the TPM1 p.Arg21Leu variant in a serie of pedigrees. METHODS: TPM1 was evaluated by next-generation sequencing in 10 561 unrelated probands with inherited heart diseases. Familial genetic screening was performed by the Sanger method. We analyzed TPM1 p.Arg21Leu pedigrees for cosegregation, clinical characteristics, and outcomes. We also estimated the geographical distribution of the carrier families in Portugal and Spain. RESULTS: The TPM1 p.Arg21Leu variant was identified in 25/4099 (0.61%) HCM-cases, and was absent in 6462 control individuals with other inherited cardiac phenotypes (P<.0001). In total, 83 carriers (31 probands) were identified. The combined LOD score for familial cosegregation was 3.95. The cumulative probability of diagnosis in carriers was 50% at the age of 50 years for males, and was 25% in female carriers. At the age of 70 years, 17% of males and 46% of female carriers were unaffected. Mean maximal left ventricular wall thickness was 21.4 ±7.65mm. Calculated HCM sudden death risk was low in 34 carriers (77.5%), intermediated in 8 (18%), and high in only 2 (4.5%). Survival free of cardiovascular death or heart transplant was 87.5% at 50 years. Six percent of carriers were homozygous and 18% had an additional variant. Family origin was concentrated in Galicia, Extremadura, and northern Portugal, suggesting a founder effect. CONCLUSIONS: TPM1 p.Arg21Leu is a pathogenic HCM variant associated with late-onset/incomplete penetrance and a generally favorable prognosis.

Utilidad clínica del estudio genético en pacientes con miocardiopatía dilatada / Clinical utility of genetic testing in patients with dilated cardiomyopathy

Introducción y objetivos: La miocardiopatía dilatada (MCD) es la causa más frecuente de trasplante cardiaco. Se considera que es familiar hasta en el 50% de los casos. Nuestro objetivo es describir los resultados genéticos obtenidos en una cohorte de pacientes con MCD, de los cuales una elevada proporción había acabado en trasplante cardiaco.MétodosSe incluyeron pacientes con MCD a los que se realizó next-generation sequencing (NGS, «secuenciación de nueva generación») de al menos 80 genes relacionados con la enfermedad. Se analizaron retrospectivamente los datos clínicos de los pacientes, la historia familiar y los resultados del estudio genético. En los casos en los que fue posible, se realizó una evaluación de sus familiares de primer grado.ResultadosFueron evaluados 87 pacientes con MCD y 308 familiares de 70 familias distintas. La prevalencia clínica de enfermedad familiar fue del 37% (32 pacientes) y el 44% (38 pacientes) habían precisado un trasplante cardiaco. En 43 pacientes (49%) se encontró al menos una variante relevante, en 25 pacientes (29%) se identificaron variantes de significado incierto y en 19 pacientes (22%) el estudio fue negativo. La mayoría de las mutaciones se encontraron en genes sarcoméricos y la rentabilidad del estudio fue mayor en los pacientes con MCD familiar.ConclusionesEl estudio genético NGS en nuestra población de pacientes con MCD tuvo una elevada rentabilidad, alcanzando el 69% en los casos familiares. El espectro mutacional fue heterogéneo y con frecuencia la identificación de la etiología específica de la enfermedad aportó información pronóstica. (AU)

Introduction and objectives: Dilated cardiomyopathy (DCM) is the most frequent cause of heart transplantation. The prevalence of familial disease can reach 50%. Our objective was to describe the genetic basis of DCM in a cohort with a high proportion of transplanted patients.MethodsWe included patients with DCM and genetic testing performed using next-generation sequencing (NGS) that included at least 80 genes. Clinical data, family history and genetic results were retrospectively analysed. When possible, assessment of first-degree relatives was carried out.ResultsEighty-seven DCM patients and 308 relatives from 70 families were evaluated. Clinical prevalence of familial disease was 37% (32 patients). Forty-four percent of patients (38 patients) had required heart transplantation. A relevant variant was found in 43 patients (49%), 25 patients (29%) carried variants of unknown significance and in 19 patients (22%) the study was negative. Most genetic variants were found in sarcomeric genes and the yield of genetic testing was higher in patients with familial DCM.ConclusionsThe yield of genetic testing in our DCM cohort was high, reaching 69% in familial cases. Mutational spectrum was heterogeneous and the identification of the specific aetiology of the disease often provided prognostic information. (AU)

Prognostic Value of Reduced Heart Rate Reserve during Exercise in Hypertrophic Cardiomyopathy.

BACKGROUND: Sympathetic dysfunction can be evaluated by heart rate reserve (HRR) with exercise test. OBJECTIVES: To determine the value of HRR in predicting outcome of patients with hypertrophic cardiomyopathy (HCM). METHODS: We enrolled 917 HCM patients (age = 49 ± 15 years, 516 men) assessed with exercise stress echocardiography (ESE) in 11 centres. ESE modality was semi-supine bicycle in 51 patients (6%), upright bicycle in 476 (52%), and treadmill in 390 (42%). During ESE, we assessed left ventricular outflow tract obstruction (LVOTO), stress-induced new regional wall motion abnormalities (RWMA), and HRR (peak/rest heart rate, HR). By selection, all patients completed the follow-up. Mortality was the predetermined outcome measure Results: During ESE, RWMA occurred in 22 patients (2.4%) and LVOTO (≥50 mmHg) in 281 (30.4%). HRR was 1.90 ± 0.40 (lowest quartile ≤ 1.61, highest quartile > 2.13). Higher resting heart rate (odds ratio 1.027, 95% CI: 1.018-1.036, p < 0.001), older age (odds ratio 1.021, 95% CI: 1.009-1.033, p < 0.001), lower exercise tolerance (mets, odds ratio 0.761, 95% CI: 0.708-0.817, p < 0.001) and resting LVOTO (odds ratio 1.504, 95% CI: 1.043-2.170, p = 0.029) predicted a reduced HRR. During a median follow-up of 89 months (interquartile range: 36-145 months), 90 all-cause deaths occurred. At multivariable analysis, lowest quartile HRR (Hazard ratio 2.354, 95% CI 1.116-4.968 p = 0.025) and RWMA (Hazard ratio 3.279, 95% CI 1.441-7.461 p = 0.004) independently predicted death, in addition to age (Hazard ratio 1.064, 95% CI 1.043-1.085 p < 0.001) and maximal wall thickness (Hazard ratio 1.081, 95% CI 1.037-1.128, p < 0.001). CONCLUSIONS: A blunted HRR during ESE predicts survival independently of RWMA in HCM patients.

Clinical utility of genetic testing in patients with dilated cardiomyopathy. / Utilidad clínica del estudio genético en pacientes con miocardiopatía dilatada.

INTRODUCTION AND OBJECTIVES: Dilated cardiomyopathy (DCM) is the most frequent cause of heart transplantation. The prevalence of familial disease can reach 50%. Our objective was to describe the genetic basis of DCM in a cohort with a high proportion of transplanted patients. METHODS: We included patients with DCM and genetic testing performed using next-generation sequencing (NGS) that included at least 80 genes. Clinical data, family history and genetic results were retrospectively analysed. When possible, assessment of first-degree relatives was carried out. RESULTS: Eighty-seven DCM patients and 308 relatives from 70 families were evaluated. Clinical prevalence of familial disease was 37% (32 patients). Forty-four percent of patients (38 patients) had required heart transplantation. A relevant variant was found in 43 patients (49%), 25 patients (29%) carried variants of unknown significance and in 19 patients (22%) the study was negative. Most genetic variants were found in sarcomeric genes and the yield of genetic testing was higher in patients with familial DCM. CONCLUSIONS: The yield of genetic testing in our DCM cohort was high, reaching 69% in familial cases. Mutational spectrum was heterogeneous and the identification of the specific aetiology of the disease often provided prognostic information.

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 evaluate the prognostic value of these assessments during exercise in patients with hypertrophic cardiomyopathy (HCM). METHODS: LV systolic function, LV-derived filling pressures, LVOT gradients, and MR were prospectively evaluated during treadmill ExE in 285 patients with HCM and preserved LV ejection fraction (EF) (≥50%). Recordings were obtained at rest and peak exercise for LV systolic function and at rest and post-exercise for LVOT gradients, MR, and ratio of early LV inflow velocity to early tissue Doppler annulus velocity (E/e´). RESULTS: Thirty-seven patients (13%) had LVOT obstruction at rest, and 76 (27%) developed exercise-induced LVOT obstruction. New wall motion abnormalities were detected in 38 patients (13%). E/e´>14 was observed in 129 patients at rest (45%) and in 134 at post-exercise (47%). Corresponding figures for significant MR (moderate or severe) were 21 (7%) and 17 (6%). During follow-up (3.9 ± 2.5 years), 27 patients had a hard event, 39 a combined event (hard plus new atrial fibrillation or syncope), and 58 a combined event or intervention. Exercise electrocardiographic testing, exercise LVEF, and the combination of positive ExE and increased E/e´ with exercise predicted outcome. The worst event rate corresponded to patients with raised E/e' values at post-exercise and positive ExE (annualized hard event-rate of 5.9%). CONCLUSIONS: A comprehensive assessment during ExE is feasible for patients with HCM and preserved LV systolic function, and provides significant incremental prognostic information.

Prognostic implications of pathogenic truncating variants in the TTN gene.

INTRODUCTION AND OBJECTIVES: TTN gene truncating variants (TTNtv) are a frequent cause of dilated cardiomyopathy (DCM). However, there are discrepant data on the associated prognosis. Our objectives were to describe the prevalence of TTNtv in our cohort and to compare the clinical course with that described in the literature. METHODS: We included patients with DCM and genetic testing performed using next-generation sequencing. Through a systematic literature research, we collected information about carriers and affected relatives with TTNtv. We compared the cumulative percentage of affected carriers and the survival free of cardiovascular death. RESULTS: One hundred and ten DCM patients were evaluated. A total of 13 TTNtv distributed in 14 probands were identified (12.7%). We found a 21.4% prevalence in familial cases. No significant differences in the relation between age and clinical disease expression were identified. Survival free of cardiovascular death curves constructed from data in the literature seems not to overestimate the risk in our population. CONCLUSIONS: The identification of TTNtv in patients with DCM is frequent and provides relevant information about the disease prognosis. The risk of cardiovascular death should not be underestimated. Age related penetrance need to be considered in the familial evaluation.

The impact of diabetes mellitus on the clinical phenotype of hypertrophic cardiomyopathy.

AIMS: Diabetes mellitus (DM) aggravates the clinical features of ischaemic and hypertensive heart diseases and worsens the prognosis of heart failure patients. Hypertrophic cardiomyopathy (HCM) and diabetes coexist fairly frequently in elderly patients but the impact of DM on the clinical phenotype of HCM is yet unknown. We sought to describe if predominant features of heart failure in DM patients exist independently in HCM. METHODS AND RESULTS: We reviewed clinical characteristics of 937 patients, age ≥40, diagnosed with HCM, from two tertiary medical centres in Spain and Israel. A propensity score matched cohort of 294 patients was also analysed. Our cohort comprised 102 HCM patients with diabetes (8.7%). Patients with DM were older at diagnosis {median 56 [interquartile range (IQR) 47-67] vs. 53 (IQR 43-63), P = 0.02} and had a higher prevalence of comorbidities. Hypertrophic cardiomyopathy patients with DM had a higher prevalence of diastolic dysfunction, pulmonary hypertension, significant mitral regurgitation, and pacemaker implantation. Hypertrophic cardiomyopathy patients with DM had a higher New York Heart Association (NYHA) class (P < 0.001) and lower exercise capacity [7.0 METS (IQR 5.0-10.0) vs. 9.0 METS (IQR 6.6-11.0), P = 0.002]. These findings were independent of age, gender, country of origin, hypertension, and coronary artery disease. Patients with diabetes had a significantly higher 15-year mortality (22% vs. 15%, P = 0.03), with no differences in sudden cardiac death, appropriate implanted cardioverter-defibrillator therapy, or heart transplantation. CONCLUSION: Hypertrophic cardiomyopathy patients with diabetes are older and have a higher cardiovascular risk profile. They have a lower functional capacity and more heart failure symptoms due to diastolic dysfunction.

Formin Homology 2 Domain Containing 3 (FHOD3) Is a Genetic Basis for Hypertrophic Cardiomyopathy.

BACKGROUND: The genetic cause of hypertrophic cardiomyopathy remains unexplained in a substantial proportion of cases. Formin homology 2 domain containing 3 (FHOD3) may have a role in the pathogenesis of cardiac hypertrophy but has not been implicated in hypertrophic cardiomyopathy. OBJECTIVES: This study sought to investigate the relation between FHOD3 mutations and the development of hypertrophic cardiomyopathy. METHODS: FHOD3 was sequenced by massive parallel sequencing in 3,189 hypertrophic cardiomyopathy unrelated probands and 2,777 patients with no evidence of cardiomyopathy (disease control subjects). The authors evaluated protein-altering candidate variants in FHOD3 for cosegregation, clinical characteristics, and outcomes. RESULTS: The authors identified 94 candidate variants in 132 probands. The variants' frequencies were significantly higher in patients with hypertrophic cardiomyopathy (74 of 3,189 [2.32%]) than in disease control subjects (18 of 2,777 [0.65%]; p < 0.001) or in the gnomAD database (1,049 of 138,606 [0.76%]; p < 0.001). FHOD3 mutations cosegregated with hypertrophic cardiomyopathy in 17 families, with a combined logarithm of the odds score of 7.92, indicative of very strong segregation. One-half of the disease-causing variants were clustered in a small conserved coiled-coil domain (amino acids 622 to 655); odds ratio for hypertrophic cardiomyopathy was 21.8 versus disease control subjects (95% confidence interval: 1.3 to 37.9; p < 0.001) and 14.1 against gnomAD (95% confidence interval: 6.9 to 28.7; p < 0.001). Hypertrophic cardiomyopathy patients carrying (likely) pathogenic mutations in FHOD3 (n = 70) were diagnosed after age 30 years (mean 46.1 ± 18.7 years), and two-thirds (66%) were males. Of the patients, 82% had asymmetric septal hypertrophy (mean 18.8 ± 5 mm); left ventricular ejection fraction <50% was present in 14% and hypertrabeculation in 16%. Events were rare before age 30 years, with an annual cardiovascular death incidence of 1% during follow-up. CONCLUSIONS: FHOD3 is a novel disease gene in hypertrophic cardiomyopathy, accounting for approximately 1% to 2% of cases. The phenotype and the rate of cardiovascular events are similar to those reported in unselected cohorts. The FHOD3 gene should be routinely included in hypertrophic cardiomyopathy genetic testing panels.

Direct oral anticoagulants in patients with hypertrophic cardiomyopathy and atrial fibrillation.

BACKGROUND: Chronic anticoagulation with vitamin K antagonists (VKAs) is recommended in patients with hypertrophic cardiomyopathy (HCM) and atrial fibrillation (AF). Direct oral anticoagulants (NOACs) are an alternative to VKAs but there are limited data to support their use in HCM. We sought to describe the pattern of use, thromboembolic events, bleeding and quality of life in patients with HCM and AF treated with NOACs. METHODS: Data from patients treated with NOACs (n=99) and VKA (n=433) at 9 inherited cardiac diseases units were retrospectively collected. Annual rates of embolic events, serious bleeding and death were analysed and compared. Quality of life and treatment satisfaction were evaluated with SF-36 and SAFUCA questionnaires in 80 NOAC-treated and 57 VKA-treated patients. RESULTS: After median follow-up of 63 months (IQR: 26-109), thromboembolic events (TIA/stroke and peripheral embolism) occurred in 10% of patients on oral anticoagulation. Major/clinically relevant bleeding occurred in 3.8% and the global mortality rate was 23.3%. Thromboembolic event rate was 0.62 per 100patient-years in the NOAC group vs. 1.59 in the VKA group [subhazard ratio (SHR) 0.32;95%CI:0.04-2.45; p=0.27]. Major/clinically relevant bleeding occurred in 0.62 per 100person-years in the NOAC group vs. 0.60 in the VKA group (SHR 1.28;95%CI 0.18-9.30; p=0.85). Quality of life scores were similar in both groups; however, NOAC-treated patients achieved higher scores in the SAFUCA. CONCLUSIONS: HCM patients with AF on NOACs showed similar embolic and bleeding rates to those on VKA. Although quality of life was similar in both groups, the NOAC group reported higher treatment satisfaction.

Extensa familia con síndrome de Marfan en la que se demuestra la patogenicidad de una variante «sinónima» (p. Ile2118=) en el gen de la fibrilina 1 / A large family with Marfan syndrome demonstrating the pathogenicity of a «synonymous» variant (p. ile2118=) in the fibrillin-1 gene

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Prognostic role of stress echocardiography in hypertrophic cardiomyopathy: The International Stress Echo Registry.

BACKGROUND: Stress echo (SE) may have a role in the outcome in patients with hypertrophic cardiomyopathy (HCM). OBJECTIVES: The aim was to assess the prognostic value of SE in a retrospective multicenter study in HCM. METHODS: We enrolled 706 HCM patients. The employed stress was exercise (n=608) and/or vasodilator (n=146, dipyridamole in 98 and adenosine in 48). We defined SE positivity according to clinical/hemodynamic criteria including: symptoms (all stress modalities), exercise-induced hypotension (failure to increase or fall >20mmHg, exercise) and exercise-induced left ventricular outflow tract obstruction (left ventricular outflow tract obstruction >50mmHg); and ischemic criteria, such as new wall motion abnormalities (new wall motion abnormality) and/or reduction of coronary flow reserve velocity (CFVR≤2.0) on left anterior descending coronary artery with vasodilator stress assessed in 116 patients. All patients completed the clinical follow-up. RESULTS: Positive SE showed more frequently CFVR reduction, exercise-induced hypotension, left ventricular outflow tract obstruction, and symptoms (38, 23, 20 and 15% respectively), but new wall motion abnormality only in 6%. During a median follow-up of 49months 180 events were observed, including 40 deaths. Clinical/hemodynamic criteria did not predict outcome (X2 0.599, p=0.598), whereas ischemia-related SE criteria (X2: 111.120, p<0.0001) was significantly related to outcome. Similarly, mortality was predicted with SE ischemic-criteria (X2 16.645, p<0.0001). CONCLUSIONS: SE has an important prognostic significance in HCM patients, with ischemia-related end-points showing greater predictive accuracy than hemodynamic endpoints. New wall motion abnormalities and impairment of CFVR should be specifically included in SE protocols for HCM.

Phenotype and prognostic correlations of the converter region mutations affecting the ß myosin heavy chain.

OBJECTIVES: The prognostic value of genetic studies in cardiomyopathies is still controversial. Our objective was to evaluate the outcome of patients with cardiomyopathy with mutations in the converter domain of ß myosin heavy chain (MYH7). METHODS: Clinical characteristics and survival of 117 affected members with mutations in the converter domain of MYH7 were compared with 409 patients described in the literature with mutations in the same region. RESULTS: Twenty-five mutations were evaluated (9 in our families including 3 novel (Ile730Asn, Asp717Gly and Arg719Pro)). Clinical diagnoses were hypertrophic (n=407), dilated (n=15), non-compaction (n=4) and restrictive (n=5) cardiomyopathies, unspecified cardiomyopathy (n=11), sudden death (n=50) and 35 healthy carriers. One hundred eighty-four had events (cardiovascular death or transplant). Median event-free survival was 50±2 years in our patients and 53±3 years in the literature (p=0.27). There were significant differences in the outcome between mutation: Ile736Thr had fewer events than other mutations in the region (p=0.01), while Arg719Gln (p<0.01) had reduced event-free survival. CONCLUSIONS: Mutations in the converter region are generally associated with adverse prognosis although there are differences between mutations. The identification of a mutation in this particular region provides important prognostic information that should be considered in the clinical management of affected patients.

Exercise echocardiography and cardiac magnetic resonance imaging to predict outcome in patients with hypertrophic cardiomyopathy.

AIMS: We have observed that wall motion abnormalities (WMAs) during exercise echocardiography (ExE) are associated to events in hypertrophic cardiomyopathy (HCM). Our objective was to evaluate ExE and cardiac magnetic resonance (CMR) to predict outcome in HCM. METHODS AND RESULTS: ExE and CMR were performed in 148 patients with HCM. During follow-up (7.1 ± 2.7 years), there were 7 hard events (Hard-E) and 26 combined events (Comb-E). Exercise WMAs were observed in 13 patients (8.8%), perfusion defects in 10 (6.8%), and late gadolinium enhancement (LGE) in 48 (32.4%). WMAs were seen in 57% of patients with Hard-E vs. 6% without (P = 0.001) and in 23 and 6% with and without Comb-E (P = 0.005). Perfusion defects were also more frequent in patients with Hard-E than without (43 vs. 5%, P = 0.007) and in patients with Comb-E than without (23 vs. 5%, P = 0.002). LGE (g) was greater in patients with Comb-E than without [median (25th-75th percentile) 0 (0-21.1) vs. 0 (0-9.3) g P = 0.04]. Univariable predictors of Comb-E included NYHA class ≥2, peak double product, ΔWMSI, and CMR data. Peak double product [Hazard ratios (HR) = 0.99, confidence intervals (CI) 95% 0.99-0.99, P = 0.02] and ΔWMSI (HR = 404, CI 95% 12-13681, P = 0.001) remained independent predictors. Peak WMSI correlated with myocardial mass with LGE (r = 0.20, P = 0.02) and with perfusion defect area (r = 0.40, P < 0.001). LGE affecting ≥15% of the left ventricle was observed in 38% of patients with exercise WMAs vs. 12% without (P = 0.009). CONCLUSION: CMR data are associated to exercise WMAs in patients with HCM. ExE and CMR may help to predict outcome in them.

Prognostic value of exercise echocardiography in patients with hypertrophic cardiomyopathy.

BACKGROUND: Although exercise echocardiography may assess left ventricular (LV) function and LV outflow tract (LVOT) gradients during exercise in patients with hypertrophic cardiomyopathy (HCM), its value for predicting outcomes has not been studied. The aim of this study was to determine whether exercise echocardiography predicts outcomes in patients with HCM. METHODS: LV function and LVOT gradients were evaluated during exercise echocardiography in 239 patients with HCM. RESULTS: Sixty patients (25.1%) had LVOT obstruction at rest, and 43 (18%) developed exercise-induced LVOT obstruction. The mean resting LV ejection fraction was 69 ± 9%, and the mean resting wall motion score index was 1.00 ± 0.06. Wall motion abnormalities during exercise were seen in 19 patients (7.9%). During follow-up of 4.1 ± 2.6 years, 19 patients had hard events (cardiac death, cardiac transplantation, appropriate discharge of a defibrillator, stroke, myocardial infarction, or hospitalization for heart failure), and 41 patients had composite end points of hard or soft events (including atrial fibrillation and syncope). Exercise wall motion abnormalities occurred in 31.5% of patients with hard events compared with 5.9% of patients without hard events (P < .001). After adjustment, LV wall thickness (hazard ratio [HR], 1.13; 95% confidence interval [CI], 1.05-1.21; P = .002), resting wall motion score index (HR, 21.59; 95% CI, 2.38-196.1, P = .006), and metabolic equivalents (HR, 0.74; 95% CI, 0.63-0.88; P = .001) remained independent predictors of hard events. Change in wall motion score index was also independently associated with hard events (HR, 52.30; 95% CI, 3.81-718.5; P = .003) and with the composite end point (HR, 39.51; 95% CI, 3.79-412.4; P = .002). LVOT obstruction was not associated with either end point. CONCLUSIONS: Assessment of exercise capacity and LV systolic function during exercise echocardiography may have a role in risk stratification of patients with HCM.

Cardiotrophin-1 plasma levels are associated with the severity of hypertrophy in hypertrophic cardiomyopathy.

AIMS: Cardiotrophin-1 (CT-1) is a cytokine that induces hypertrophy in cardiomyocytes and is associated with left ventricular hypertrophy (LVH) in hypertensive patients. The objective of this study was to evaluate whether plasma CT-1 is associated with hypertrophic cardiomyopathy (HCM). METHODS AND RESULTS: The study was performed in 124 patients with HCM. All patients underwent a full clinical evaluation and an echocardiogram. Left ventricular hypertrophy was evaluated by the measurement of the maximal LV wall thickness and the Spirito's LVH score. Plasma CT-1 was measured by an enzyme-linked immunosorbent assay. Compared with controls, patients with HCM exhibited higher (P < 0.001) plasma CT-1 levels. Significant correlations were found between CT-1 and maximal LV wall thickness (r = 0.284, P = 0.001) and the Spirito's LVH score (r = 0.287, P = 0.006) in HCM patients. In addition, the levels of CT-1 were higher (P = 0.02) in patients with severe LVH (maximal LV wall thickness ≥30 mm) than in patients with mild or moderate LVH (maximal LV wall thickness <30 mm). CONCLUSIONS: These findings show that plasma CT-1 is associated with the severity of LVH in patients with HCM. Further studies are required to ascertain whether CT-1 is a diagnostic biomarker of this cardiomyopathy.

Severe cardiac conduction disturbances and pacemaker implantation in patients with hypertrophic cardiomyopathy.

The aims of this study were to determine the prevalence of severe cardiac conduction disturbances in a cohort of 451 patients with hypertrophic cardiomyopathy and to describe the characteristics of, and outcomes in, those who required a permanent pacemaker. A pacemaker was implanted in 48 patients (11%): 20 had sinus node dysfunction and 28 had an atrioventricular conduction disturbance. Primary bradyarrhythmia (which was not related to iatrogenic atrioventricular block or therapeutic ablation of the atrioventricular node) was the reason for permanent pacemaker implantation in 36 patients (8%). In 18% of cases, at least one other family member had a permanent pacemaker. In this patient series, a high prevalence of severe cardiac conduction disturbance leading to permanent pacemaker implantation was observed. Severe cardiac conduction disturbance in hypertrophic cardiomyopathy may also have a familial component.

Trastornos graves de la conducción cardiaca e implante de marcapasos en pacientes con miocardiopatía hipertrófica / Severe cardiac conduction disturbances and pacemaker implantation in patients with hypertrophic cardiomyopathy

El objetivo de este estudio es analizar la prevalencia de trastornos graves de la conducción cardiaca en una cohorte de 451 pacientes con miocardiopatía hipertrófica, describiendo las características y la evolución de aquellos que requirieron marcapasos. En 48 pacientes (11%) se implantó un marcapasos: 20 casos por disfunción del nodo sinusal y 28 casos por trastorno de la conducción auriculoventricular. Las bradiarritmias primarias (las no relacionadas con bloqueo auriculoventricular iatrogénico o ablación terapéutica del nodo auriculoventricular) fueron causa de implante en 36 pacientes (8%). En un 18% se detectó un marcapasos en al menos otro miembro de la familia. En nuestra serie, encontramos una elevada prevalencia de trastornos graves de la conducción cardiaca que determinaron el implante de marcapasos. Los trastornos severos de la conducción en la miocardiopatía hipertrófica tienen también una presentación familiar (AU)

The aims of this study were to determine the prevalence of severe cardiac conduction disturbances in a cohort of 451 patients with hypertrophic cardiomyopathy and to describe the characteristics of, and outcomes in, those who required a permanent pacemaker. A pacemaker was implanted in 48 patients (11%): 20 had sinus node dysfunction and 28 had an atrioventricular conduction disturbance. Primary bradyarrhythmia (which was not related to iatrogenic atrioventricular block or therapeutic ablation of the atrioventricular node) was the reason for permanent pacemaker implantation in 36 patients (8%). In 18% of cases, at least one other family member had a permanent pacemaker. In this patient series, a high prevalence of severe cardiac conduction disturbance leading to permanent pacemaker implantation was observed. Severe cardiac conduction disturbance in hypertrophic cardiomyopathy may also have a familial component (AU)

Screening mutations in myosin binding protein C3 gene in a cohort of patients with Hypertrophic Cardiomyopathy.

BACKGROUND: MyBPC3 mutations are amongst the most frequent causes of hypertrophic cardiomyopathy, however, its prevalence varies between populations. They have been associated with mild and late onset disease expression. Our objectives were to establish the prevalence of MyBPC3 mutations and determine their associated clinical characteristics in our patients. METHODS: Screening by Single Strand Conformation Polymorphisms (SSCP) and sequencing of the fragments with abnormal motility of the MyBPC3 gene in 130 unrelated consecutive HCM index cases. Genotype-Phenotype correlation studies were done in positive families. RESULTS: 16 mutations were found in 20 index cases (15%): 5 novel [D75N, V471E, Q327fs, IVS6+5G>A (homozygous), and IVS11-9G>A] and 11 previously described [A216T, R495W, R502Q (2 families), E542Q (3 families), T957S, R1022P (2 families), E1179K, K504del, K600fs, P955fs and IVS29+5G>A]. Maximum wall thickness and age at time of diagnosis were similar to patients with MYH7 mutations [25(7) vs. 27(8), p = 0.16], [46(16) vs. 44(19), p = 0.9]. CONCLUSIONS: Mutations in MyBPC3 are present in 15% of our hypertrophic cardiomyopathy families. Severe hypertrophy and early expression are compatible with the presence of MyBPC3 mutations. The genetic diagnosis not only allows avoiding clinical follow up of non carriers but it opens new possibilities that includes: to take preventive clinical decisions in mutation carriers than have not developed the disease yet, the establishment of genotype-phenotype relationship, and to establish a genetic diagnosis routine in patients with familial HCM.