University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

191

Pages:

2
Author:

Mariam A. A.

Cardiovascular Genetics Inherited Cardiovascular Diseases Long QT syndrome: QTc interval is the QT interval adjust by heart rate − QTc interval > 440 milliseconds is considered prolonged. − 450 to 470 milliseconds are considered borderline. − The average QTc for someone who has Long-QT Syndrome is 490 milliseconds. Symptoms • Symptoms only develop with an episode of torsades de pointes (polymorphic ventricular tachycardia) o A few seconds: Extreme Dizziness o More than 10 seconds: syncope o More than a few minutes: death Mechanism • In most cases there is a mutation in the genes which code for one of the ion channels o Jo Lind said remember one example: So LQT1 syndrome is caused by a mutation in the gene KCNQ1 which encodes for the Ik5 potassium channel α subunit • There are various phenotypes of LQ, depending on the gene affected and how it is affected o These phenotypes can be exacerbated by particular environmental conditions Hypertrophic Cardiomyopathy: Hypertrophic cardiomyopathy (HCM) is a condition in which the heart muscle becomes thick. The thickening makes it harder for blood to leave the heart, forcing At least 11 causative genes identified the heart to work harder to pump blood. Hypertrophic cardiomyopathy is often asymmetrical. Dilated Cardiomyopathy: Dilated cardiomyopathy (DCM) is a condition in which the heart becomes weakened and enlarged and cannot pump blood efficiently. The decreased heart function can affect the lungs, liver, and other body systems. For many individual, dilated cardiomyopathy is a condition which will not limit the quality of life. Some people experience significant symptoms and there is sometimes a risk of sudden death. In some patients, symptoms of left- and right-sided congestive heart failure develop gradually. Arrhythmogenic Right Ventricular Cardiomyopathy: The disease is a type of non-ischaemic cardiomyopathy that involves primarily the right ventricle. It is characterised by hypokinetic areas involving the free wall of the right ventricle, with fibro-fatty replacement of the right ventricular myocardium, + associated arrhythmias originating in the right ventricle. Genetic Testing – ARVC is an autosomal dominant trait with reduced penetrance – there is mutation identified in one of several genes encoding components of the desmosomes. If the cell-cell interactions are insufficiently tight, damage may occur more easily at places where these forces then exert their most unfavourable effects. Treatment / management – Implantable defibrillator can constantly monitor the rate and rhythm of the heart + can deliver therapies by way of an electrical shock when electrical manifestations of the heart activity exceed the preset number. Some of the many genes identified to be associating with the problem.