Left Ventricular Systolic Dysfunction (LVSD, but commonly referred to as heart failure) is a chronic, progressive cardiac syndrome in which a damaged heart fails to beat efficiently and deliver enough blood to meet the body's needs. Although coronary heart disease (CHD) is the most common cause, for example, myocardial infarction, and many of the conditions are intertwined, there are several other causes of heart failure including cardiomyopathies, hypertension and valve disease.
Cardiomyopathies can be caused by genetic disorders/defects, viral illness, some endocrine conditions, autoimmune diseases, and excessive use of alcohol and drugs. Pharmacology treatment of diagnosed LVSD is predominately the same, although it is recognised that lifestyle advice may differ depending on the cause or exposure to environmental factors.
For the purpose of this assessment I have chosen to focus upon cardiomyopathy which have commonly been subdivided into a specific diagnosis of either hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), restrictive cardiomyopathy (RCM) and arrhythmogenic right ventricular dysplasia (ARVD). HCM and DCM are commonly ‘diagnosed’ separately and as an individual diagnosis but there is suggestion that a single gene defect can result in the syndrome of heart failure.
Mrs Jane Thomson is a 24 year old lady with a diagnosis of heart failure with an underlying cause of hypertrophic cardiomyopathy, the only other feature in her past medical history was of bulimia during her teenage years. Hypertrophic cardiomyopathies often have a preserved systolic function with an impaired left ventricular compliance and diastolic dysfunction but Jane also had signs and symptoms of left ventricular dysfunction.
Diagram available online at http://adam.about.com/reports/Hypertrophic-cardiomyopathy.htm
There was evidence in Jane’s family history/family tree of sudden deaths in younger relatives and it was identified through more detailed genetic testing blood test that the sarcomere protein MYH7 gene on chromosome 14 was defective in her and some of her immediate extended family. Some family members had sudden early deaths and no other current family members identified with the deficient gene showed signs and symptoms of heart failure.
Mutations and misprints of gene MYBPC3 have also been shown to be present in individuals with HCA (Zaragoza et al, 2007) but this was not identified in Jane or her extended family. Some family members had sudden infant/young deaths, and as mentioned earlier, some carried the defective gene with no obvious problems. This leads us to the suggestion that perhaps environmental factors could also have contributed to the homeostatic imbalances Jane was experiencing.
Morita (2005) stated that ‘recent insights into molecular genetic causes of myocardial diseases have highlighted the importance of single-gene defects in the pathogenesis of heart failure’. The...