Where genome meets phenome: rationale for integrating genetic and protein biomarkers in the diagnosis and management of dilated cardiomyopathy and heart failure.

This review provides the rationale for integrating genomic and protein biomarkers in the evolving diagnosis and management of dilated cardiomyopathy (DCM) and its causal pathway to heart failure (HF), with a larger objective to serve as a template for genomic and phenomic profiling of other cardiovascular disease. DCM is a major cause of HF and accounts for more than half of heart transplantation in adults and children worldwide. DCM may remain asymptomatic for years, but HF and/or arrhythmias, both late manifestations of the disease, ultimately cause significant morbidity and mortality. A significant proportion of DCM has a genetic etiology. DCM can also result from environmental injury such as infection, toxins, or catecholamine excess. While molecular genetic testing can identify those at risk for genetic DCM, epigenetic and sentinel phenomic staging can help to identify those at highest risk in need for intervention. Phenomic staging includes integrating clinical and imaging features, transcriptomics, higher order proteomics and metabolomics interactions, and epidemiological data. This principle can be applied in family members of patients with DCM, where genetic testing and clinical phenotyping are indicated. This will allow the design of specific interventions tailored to individuals sharing similar risks, to alter the natural history of DCM and obviate complications such as HF/arrhythmias.

Diastolic heart failure: progress, treatment challenges, and prevention.

Diastolic heart failure (DHF) is an important entity, the significance of which is increasingly recognized. This report examines the available evidence regarding the role, significance, and mechanisms of DHF. Epidemiologic studies have documented the rising burden of DHF, and experimental data are revealing the unique mechanisms distinguishing it from systolic heart failure. Despite controversies on the definition of DHF, or heart failure with preserved ejection fraction, standardized clinical criteria with supplementary imaging and structural data have identified DHF as a distinct pathophysiological entity. The mechanisms underlying DHF include abnormal matrix dynamics, altered myocyte cytoskeleton, and impaired active relaxation. The commonly held belief that survival of patients with DHF is better than that of patients with systolic heart failure has been challenged by updated data. The heterogeneous etiologies or risk factors for the condition include aging, diabetes, hypertension, and ischemia, making a common diagnostic or treatment pathway difficult. Novel therapeutic targets that address the pathophysiology of this disease are under consideration, although there are no proven therapies for DHF to date. Exacerbating factors include volume and sodium indiscretion, arrhythmias, ischemia, and comorbidities. Strategies to ameliorate or to obviate these precipitating factors are most effective in preventing DHF and its exacerbations. Meanwhile, prevention of DHF through appropriate and aggressive risk factor identification and management must remain the cornerstone of clinical intervention.

Prevalence and determinants of anemia in adults with complex congenital heart disease and ventricular dysfunction (subaortic right ventricle and single ventricle physiology).

Anemia is well recognized as a marker of poor prognosis in patients with acquired heart disease and heart failure. Adults with complex congenital heart disease and ventricular dysfunction (subaortic right ventricle or single-ventricle physiology) represent a different population, because they are typically much younger and have less co-morbidity compared with patients with acquired forms of heart disease. The purpose of this study was to evaluate the prevalence and determinants of anemia in this population. Baseline hemoglobin levels were recorded at the time of the initial clinic visit, and final hemoglobin levels were those recorded before death or transplantation or at study completion. Anemia was defined as hemoglobin <135 g/L in men and <120 g/L in women. One hundred sixty-seven patients (100 men, mean age 34 +/- 8 years, mean ejection fraction 35 +/- 9%) were included, 66 with atrial switch operations, 42 with congenitally corrected transposition of the great arteries, and 59 with Fontan physiology. The mean hemoglobin level at baseline was 149 +/- 22 g/L and at follow-up was 139 +/- 29 g/L. The overall prevalence of anemia was 29% at completion. Hyponatremia, decreased renal function, and the use of warfarin were independent predictors of anemia. In conclusion, anemia is common in patients with complex congenital heart disease and ventricular dysfunction, in particular those with Fontan physiology.

Anticonvulsant actions of gap junctional blockers in an in vitro seizure model.

Gap junctions (gjs) are increasingly recognized as playing a significant role in seizures. We demonstrate that different types of gap junctional blocking agents reduce the duration of evoked seizure-like primary afterdischarges (PADs) in the rat in vitro CA1 hippocampal pyramidal region, following repetitive tetanization of the Schaffer collaterals. Intracellular acidosis, which is known to block gap junctional communication, decreased the PADs, whereas alkalinization increased the PADs. Cellular excitability was not significantly depressed as determined by input/output relations recorded before and during perfusion of the gj blockers blockers carbenoxolone and sodium propionate. There was a small decrease following 1-octanol perfusion and a large decrease following NH(4)Cl application. Carbenoxolone diminished PAD duration, but increased neuronal excitability in whole-cell recordings. After robust PADs were established, the expression of several gj proteins including connexins (Cxs) 26, 32, 36, and 43, as measured by Western blotting, was unchanged, although the level of nonphosphorylated Cx43 was decreased. Our data support the concept that blocking gap junctional communication is an anticonvulsant mechanism.

Heart failure and ventricular dysfunction in patients with single or systemic right ventricles.

BACKGROUND: Previous studies suggested a high incidence of congestive heart failure in patients with single and/or systemic right ventricles. The corresponding risk in an adult population is unknown. METHODS AND RESULTS: A cohort of 188 consecutive adult patients with single or systemic right ventricles was prospectively assessed with gated radionuclide angiography (n=135) or 2D echocardiography (n=188) and followed up clinically. Clinical assessment showed 82.4% of the patients were in New York Heart Association class I or II, 13.3% were in class III, and 4.3% were in class IV. Heart failure occurred in 22.2% of patients with transposition of the great arteries and a Mustard procedure, 32.3% of patients with congenitally corrected transposition of the great arteries, and 40% of Fontan-palliated patients. Symptomatic patients had significantly lower anaerobic thresholds (10.3 +/- 2.8 versus 13.2 +/- 4.8 mL center dot kg(-1) center dot min(-1), P=0.006) and peak (center dot)VO(2) (15.2 +/- 4.8 versus 20.3 +/- 6.8 mL center dot kg(-1) center dot min(-1), P<0.00029). Systemic ventricular ejection fraction in symptomatic versus asymptomatic patients at rest was 34.8 +/- 15.7% versus 46.7 +/- 13.4% (P=0.00001). Mortality was 47.1% among symptomatic patients and 5% among asymptomatic patients at 15.7 years of postoperative follow-up. Seven of 12 patients with potentially correctable surgical lesions died or persisted in heart failure despite surgery. Best predictors for mortality were New York Heart Association class, systemic ejection fraction, and age at operation. CONCLUSIONS: Patients with single or systemic right ventricles have significant risk for heart failure accompanied by high mortality. This study suggests the importance of identifying this group of patients who are at risk for heart failure and considering strategies to preserve ventricular function.