Evolving Approaches to Genetic Evaluation of Specific Cardiomyopathies

Contemporary genetic testing in inherited cardiac disease: tools, ethical issues, and clinical applications

Inherited cardiac diseases comprise a wide and heterogeneous spectrum of diseases of the heart, including the cardiomyopathies and the arrhythmic diseases in structurally normal hearts, that is, channelopathies. With a combined estimated prevalence of 3% in the general population, these conditions represent a relevant epidemiological entity worldwide, and are a major cause of cardiac morbidity and mortality in the young. The extraordinary progress achieved in molecular genetics over the last three decades has unveiled the complex molecular basis of many familial cardiac conditions, paving the way for routine use of gene testing in clinical practice. In current practice, genetic testing can be used in a clinically affected patient to confirm diagnosis, or to formulate a differential diagnosis among overlapping phenotypes or between hereditary and acquired (nongenetic) forms of disease. Although genotype–phenotype correlations are generally unpredictable, a precise molecular diagnosis can help predict prognosis in specific patient subsets and may guide management. In clinically unaffected relatives, genetic cascade testing is recommended, after the initial identification of a pathogenic variation, with the aim of identifying asymptomatic relatives who might be at risk of disease-related complications, including unexpected sudden cardiac death. Future implications include the identification of novel therapeutic targets and development of tailored treatments including gene therapy. This document reflects the multidisciplinary, ‘real-world’ experience required when implementing genetic testing in cardiomyopathies and arrhythmic syndromes, along the recommendations of various guidelines.

Left ventricular hypertrabeculation/noncompaction, cardiac phenotype, and neuromuscular disorders

BACKGROUND

The prognosis of patients with left ventricular hypertrabeculation/noncompaction (LVHT) and its association with neuromuscular disorders (NMDs) is a controversial topic. The aim of this study was to assess whether the prognosis of LVHT patients is dependent on cardiac phenotype and the presence of NMDs.

METHODS

Consecutive patients who were diagnosed with LVHT between 1995 and 2016 were included in the study. Cardiac phenotype was classified according to the recommendations of the European Society of Cardiology as: "dilated" if the left ventricular end-diastolic diameter (LVEDD) was >57 mm and left ventricular fractional shortening (FS) was ≤25%; "hypertrophic" if LVEDD was ≤57 mm, FS > 25%, and left ventricular posterior wall (LVPWT) and interventricular septal thickness (IVST) were both >13 mm; "intermediate" if LVEDD was >57 mm and FS > 25% or if LVEDD was ≤57 mm and FS ≤ 25%; and "normal" if LVEDD was ≤57 mm, FS > 25%, and IVST and LVPWT ≤ 13 mm. Therapy was carried out by the treating physicians.

RESULTS

LVHT was diagnosed in 273 patients (80 females, 53 ± 16 years). The phenotype was assessed as dilated in 46%, hypertrophic in 8%, intermediate in 17%, and normal in 29% of the patients. Of these patients, 72% underwent neurological examinations, and an NMD was found in 76%. Over a period of 7.4 years (±5.7), 84 patients died and six underwent cardiac transplantation. The highest mortality rate was observed in the dilated and the lowest in the hypertrophic cardiac phenotype groups. Among the dilated phenotype, mortality was higher in patients with than without NMDs.

CONCLUSION

Patients with LVHT and dilated cardiac phenotype have a worse prognosis than patients with a hypertrophic or intermediate/normal cardiac phenotype, especially if they suffer from NMDs.

Redefining the role of biomarkers in heart failure trials: expert consensus document

Heart failure is a growing cardiovascular disease with significant epidemiological, clinical, and societal implications and represents a high unmet need. Strong efforts are currently underway by academic and industrial researchers to develop novel treatments for heart failure. Biomarkers play an important role in patient selection and monitoring in drug trials and in clinical management. The present review gives an overview of the role of available molecular, imaging, and device-derived digital biomarkers in heart failure drug development and highlights capabilities and limitations of biomarker use in this context.

Circulating Biomarkers in Heart Failure

Biological markers have served for diagnosis, risk stratification and guided therapy of heart failure (HF). Our knowledge regarding abilities of biomarkers to relate to several pathways of HF pathogenesis and reflect clinical worsening or improvement in the disease is steadily expanding. Although there are numerous clinical guidelines, which clearly diagnosis, prevention and evidence-based treatment of HF, a strategy regarding exclusion of HF, as well as risk stratification of HF, nature evolution of disease is not well established and requires more development. The aim of the chapter is to discuss a role of biomarker-based approaches for more accurate diagnosis, in-depth risk stratification and individual targeting in treatment of patients with HF.