Sudden death in hypertrophic cardiomyopathy

Article Abstract:

A study of implantable defibrillators in patients with hypertrophic cardiomyopathy conclusively shows that ventricular tachycardia or ventricular fibrillation is the cause of most sudden deaths in these patients. Hypertrophic cardiomyopathy is a disease of heart muscle. The study showed that an implantable defibrillator could stop these arrhythmias soon after they start. These devices are surgically inserted in the chest and deliver a shock to the heart whenever an arrhythmia begins. Only one-third of the patients had a history of cardiac arrest. The others received the device to prevent a first occurrence of cardiac arrest.

Health aspects, Care and treatment, Editorial, Prevention, Sudden death, Defibrillators, Cardiovascular instruments, Implanted, Cardiovascular implants

---

Preclinical diagnosis of familial hypertrophic cardiomyopathy by genetic analysis of blood lymphocytes

Article Abstract:

Familial hypertrophic cardiomyopathy causes the enlargement of the heart muscle; this disorder is inherited as a dominant trait. Unfortunately, it has been difficult to diagnose this disease until the heart muscle has already become hypertrophic. Children carrying the gene often have no clinical abnormalities, and sometimes the sudden death of a young adult is the first indication that something is wrong. It would be valuable to have a genetic test, both for the purpose of counselling patients and also for the possible development of preventive interventions. Previous research has shown that the disease gene is located close to and on the same chromosome as the gene for a portion of the myoglobin molecule (specifically, the heavy chain). Since myoglobin is an important constituent of muscle tissue, this gene seemed to be the best place to look for specific mutations using the techniques of molecular biology. The gene for the heavy chain of beta cardiac myosin is transcribed by lymphocytes circulating in the blood. Why these cells transcribe this gene is not known, but this phenomenon, called ectopic transcription, provides researchers with the convenient opportunity to use blood, rather than heart muscle biopsy, for genetic testing. Using reverse transcription to make a DNA copy of the RNA from the lymphocytes and then amplifying the DNA using the polymerase chain reaction, researchers were able to obtain enough DNA for analysis from a patient with familial hypertrophic cardiomyopathy and from 15 adult family members. A mutation in the beta cardiac myosin heavy chain was found in the patient and in eight relatives. When 14 family members under 21 were then examined for this mutation, it was found in seven. These seven individuals included five who had already developed abnormalities detectable by electrocardiography (ECG). The sensitivity of the genetic test was illustrated by the positive finding in two children, two and four years of age, who did not yet have signs of heart disorders. It is anticipated that these children will develop signs and symptoms as they grow older. It was concluded that the seven remaining children and their future offspring were not at risk for this familial heart disorder. (Consumer Summary produced by Reliance Medical Information, Inc.)

Diagnosis, Myoglobin, Lymphocytes

---

Characteristics and prognostic implications of myosin missense mutations in familial hypertrophic cardiomyopathy

Article Abstract:

Fifty percent of families with the genetic disorder familial hypertrophic cardiomyopathy may have a mutation in the gene that encodes for the heavy-chain portion of beta cardiac myosin, or heart muscle protein. Familial hypertrophic cardiomyopathy is a form of heart disease that can cause sudden death in adolescents and young adults. Of 25 unrelated families with familial hypertrophic cardiomyopathy, 12 of the families had mutations in the heavy-chain gene of beta cardiac myosin. Seven different types of mutations occurred among the 12 families. All were missense mutations, or mutations in which one amino acid of a protein is substituted for another. Six of the mutations involved the substitution of an amino acid with a different charge than that of amino acid in the normal protein. Individuals with this type of mutation had a significantly shorter life expectancy, of only 33 years on average, compared to those with a mutation that did not change the amino acid charge. Individuals with different types of mutations had the same symptoms.

Myosin

Similar abstracts:

• Abstracts: Magnitude of left ventricular hypertrophy and risk of sudden death in hypertrophic cardiomyopathy. The upper limit of physiologic cardiac hypertrophy in highly trained elite athletes
• Abstracts: Cost and enrollment implications of targeting different source population for an HIV treatment program. Cost-effective use of nevirapine to prevent vertical HIV transmission in sub-Saharan Africa
• Abstracts: Mutations in the gene for cardiac myosin-binding protein C and late-onset familial hypertrophic cardiomyopathy
• Abstracts: Efficacy of bilateral prophylactic mastectomy in women with a family history of breast cancer. Breast cancer after prophylactic bilateral mastectomy in women with a BRCA1 or BRCA2 mutation
• Abstracts: The risks of spontaneous preterm delivery and perinatal mortality in relation to size at birth according to fetal versus neonatal growth standards

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.