Extracardiac medical and neuromuscular implications in restrictive cardiomyopathy

Translating emerging molecular genetic insights into clinical practice in inherited cardiomyopathies

Cardiomyopathies are primarily genetic disorders of the myocardium associated with higher risk of life-threatening cardiac arrhythmias, heart failure, and sudden cardiac death. The evolving knowledge in genomic medicine during the last decade has reshaped our understanding of cardiomyopathies as diseases of multifactorial nature and complex pathophysiology. Genetic testing in cardiomyopathies has subsequently grown from primarily a research tool into an essential clinical evaluation piece with important clinical implications for patients and their families. The purpose of this review is to provide with a contemporary insight into the implications of genetic testing in diagnosis, therapy, and prognosis of patients with inherited cardiomyopathies. Here, we summarize the contemporary knowledge on genotype-phenotype correlations in inherited cardiomyopathies and highlight the recent significant achievements in the field of translational cardiovascular genetics.

Cardiomyopathy in neurological disorders

According to the American Heart Association, cardiomyopathies are classified as primary (solely or predominantly confined to heart muscle), secondary (those showing pathological myocardial involvement as part of a neuromuscular disorder) and those in which cardiomyopathy is the first/predominant manifestation of a neuromuscular disorder. Cardiomyopathies may be further classified as hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, or unclassified cardiomyopathy (noncompaction, Takotsubo-cardiomyopathy). This review focuses on secondary cardiomyopathies and those in which cardiomyopathy is the predominant manifestation of a myopathy. Any of them may cause neurological disease, and any of them may be a manifestation of a neurological disorder. Neurological disease most frequently caused by cardiomyopathies is ischemic stroke, followed by transitory ischemic attack, syncope, or vertigo. Neurological disease, which most frequently manifests with cardiomyopathies are the neuromuscular disorders. Most commonly associated with cardiomyopathies are muscular dystrophies, myofibrillar myopathies, congenital myopathies and metabolic myopathies. Management of neurological disease caused by cardiomyopathies is not at variance from the same neurological disorders due to other causes. Management of secondary cardiomyopathies is not different from that of cardiomyopathies due to other causes either. Patients with neuromuscular disorders require early cardiologic investigations and close follow-ups, patients with cardiomyopathies require neurological investigation and avoidance of muscle toxic medication if a neuromuscular disorder is diagnosed. Which patients with cardiomyopathy profit most from primary stroke prevention is unsolved and requires further investigations.

Delineating the role of alterations in lipid metabolism to the pathogenesis of inherited skeletal and cardiac muscle disorders: Thematic Review Series: Genetics of Human Lipid Diseases

As the specific composition of lipids is essential for the maintenance of membrane integrity, enzyme function, ion channels, and membrane receptors, an alteration in lipid composition or metabolism may be one of the crucial changes occurring during skeletal and cardiac myopathies. Although the inheritance (autosomal dominant, autosomal recessive, and X-linked traits) and underlying/defining mutations causing these myopathies are known, the contribution of lipid homeostasis in the progression of these diseases needs to be established. The purpose of this review is to present the current knowledge relating to lipid changes in inherited skeletal muscle disorders, such as Duchenne/Becker muscular dystrophy, myotonic muscular dystrophy, limb-girdle myopathic dystrophies, desminopathies, rostrocaudal muscular dystrophy, and Dunnigan-type familial lipodystrophy. The lipid modifications in familial hypertrophic and dilated cardiomyopathies, as well as Barth syndrome and several other cardiac disorders associated with abnormal lipid storage, are discussed. Information on lipid alterations occurring in these myopathies will aid in the design of improved methods of screening and therapy in children and young adults with or without a family history of genetic diseases.

Cardiac abnormalities in Anderson-Fabry disease and Fabry's cardiomyopathy

Fabry's disease is an X-linked lysosomal storage disease most often associated with renal dysfunction and death due to renal failure in patients' fourth and fifth decades of life. However, cardiac manifestations including arrhythmias, angina and heart failure are common and probably underrecognized. Furthermore, Fabry's disease is now recognised as also affecting female carriers, who manifest signs later than males. A variant of Fabry's has been identified that only affects cardiac tissue, which presents as an unexplained hypertrophy of the left ventricle in middle-aged patients, possibly with women more affected than men. Given that epidemiological studies report a prevalence of Fabry's cardiomyopathy among middle-aged patients with cardiac hypertrophy to be anywhere from one to 12%, it is reasonable to screen these patients for alpha-galactosidase A deficiency. Although mortality data is lacking from randomised, controlled trials of galactosidase replacement therapy, there are some reports of improvement in cardiac endpoints. Therefore patients with known Fabry's disease should be screened early for cardiac involvement, as treatment benefit may not be seen once cardiac fibrosis has developed.

A retro-inverso TAT-like peptide designed to deliver cysteamine to cells

A retro-inverso, TAT-like peptide wherein lysine residues are replaced with cysteine residues bearing a disulfide-linked cysteamine group is found to engage in thiol-disulfide exchange with cysteine. These peptides are transported into cells and localize to lysosomes. Cellular uptake is enhanced in peptides bearing two cysteamine groups over those with one or none, by factors of approximately 1.5 and 12, respectively.

Management of patients undergoing multivalvular surgery for carcinoid heart disease: the role of the anaesthetist

BACKGROUND

The management of patients with carcinoid heart disease poses two major challenges for the anaesthetist: carcinoid crisis and low cardiac output secondary to right ventricular (RV) failure. Carcinoid crises may be precipitated by the administration of catecholamines and histamine-releasing drugs.

METHODS

We analysed a series of 11 patients [six males, median (range) age 60 (42-73) yr] with severe symptomatic carcinoid heart disease who underwent multivalve surgery (right-sided valves, n=8; right- and left-sided valves, n=3) between 2001 and 2007.

RESULTS

All patients received octreotide intraoperatively [650 (300-1050) microg] to prevent carcinoid symptoms and vasoplegia. Those patients on a greater preoperative octreotide regime required additional intraoperative octreotide [median (range) dose 320 (300-850) vs 750 (650-1050) mug]. Similarly, the use of greater doses of aprotinin (> 5 KIU) was associated with greater requirements for octreotide [475 (300-700) vs 750 (320-1050) microg] and higher glucose levels (> or =8.5 mmol litre(-1)). Catecholamines were generally required in those patients who presented with a worse New York Heart Association functional class. Overall mortality was 18% (n=2) and only one episode of mild intraoperative carcinoid crisis was observed.

CONCLUSIONS

Carcinoid crisis and RV failure still remain the primary challenges for the anaesthesiologist while managing patients with carcinoid heart disease. Our study supports the administration of catecholamines to wean patients off cardiopulmonary bypass, particularly in the presence of myocardial dysfunction. Those patients on higher octreotide dosages may require close intraoperative glucose monitoring. Despite high operative mortality, surgical outcome has been improved potentially due to earlier patient referral and better perioperative management.