In about 60 to 70% of the cases, cardiac MRI shows thickening of more than 15 mm of the lower part of the ventricular septum. T1-weighted imaging may identify scarring of cardiac tissues while T2-weighted imaging may identify oedema and inflammation of cardiac tissue which is associated with acute clinical signs of chest pain and fainting episodes.Pulsus bisferiens may occasional be found during examination. Variants
Depending on whether the distortion of normal heart anatomy causes an obstruction of the outflow of blood from the left ventricle of the heart, HCM can be classified as obstructive or non-obstructive. The obstructive variant of HCM is hypertrophic obstructive cardiomyopathy (HOCM), also historically known as idiopathic hypertrophic subaortic stenosis(IHSS) or asymmetric septal hypertrophy (ASH). The diagnosis of left ventricular outflow tract obstruction is usually made by echocardiographic assessment and is defined as a peak left ventricular outflow tract gradient of ≥ 30 mmHg.Another, non-obstructive variant of HCM is apical hypertrophic cardiomyopathy (AHC), also called Yamaguchi syndrome. It was first described in individuals of Japanese descent. Cardiac catheterization
Upon cardiac catheterization, catheters can be placed in the left ventricle and the ascending aorta, to measure the pressure difference between these structures. In normal individuals, during ventricular systole, the pressure in the ascending aorta and the left ventricle will equalize, and the aortic valve is open. In individuals with aortic stenosis or with HCM with an outflow tract gradient, there will be a pressure gradient (difference) between the left ventricle and the aorta, with the left ventricular pressure higher than the aortic pressure.
Hypertrophic cardiomyopathy (HCM, or HOCM when obstructive) is a condition in which the heart becomes thickened without an obvious cause. The parts of the heart most commonly affected are the interventricular septum and the ventricles. This results in the heart being less able to pump blood effectively and also may cause electrical conduction problems.People who have HCM may have a range of symptoms. People may be asymptomatic, or may have fatigue, leg swelling, and shortness of breath. It may also result in chest pain or fainting. Symptoms may be worse when the person is dehydrated. Complications may include heart failure, an irregular heartbeat, and sudden cardiac death.HCM is most commonly inherited from a persons parents in an autosomal dominant pattern. It is often due to mutations in certain genes involved with making heart muscle proteins. Other inherited causes of left ventricular hypertrophy may include Fabry disease, Friedreichs ataxia, and certain medications such as tacrolimus. Other considerations for causes of enlarged heart are athletes heart and hypertension (high blood pressure). Making the diagnosis of HCM often involves a family history or pedigree, an electrocardiogram, echocardiogram, and stress testing. Genetic testing may also be done. HCM can be distinguished from other inherited causes of cardiomyopathy by its autosomal dominant pattern, whereas Fabry disease is X-linked and Friedreichs Ataxia is inherited in an autosomal recessive pattern.Treatment may depend on symptoms and other risk factors. Medications may include the use of beta blockers or disopyramide.