Ask the Doctors November 2014 Issue

Ask The Doctors: November 2014

I found out that I have hypertrophic cardiomyopathy (HCM) and that it may be an inherited condition. I really don’t have any symptoms, but I understand it can be serious. Can you tell me a little about HCM?

HCM is a primary disorder of the cardiac muscle cells, which are enlarged and arranged in a disorganized fashion. When cardiologists evaluate HCM with an echocardiogram, they see a dramatically-thickened septum (muscle between left and right ventricles). The wider septum along with other factors can actually choke off the flow of blood being pumped from the left ventricle to the aorta. This worrisome feature is known as dynamic outflow tract obstruction, and is worsened by intense contraction of the heart during exercise, dehydration, and drugs which dilate blood vessels (vasodilators). Such obstruction drops blood pressure, reduces blood flow through the coronary arteries, and can lead to chest discomfort, shortness of breath, palpitations, loss of consciousness (syncope) and even sudden death due to abnormal cardiac electrical activity (arrhythmias). Patients with symptoms from obstructive HCM are generally advised to avoid vigorous exercise, dehydration, and diuretic or vasodilator drugs. They are often prescribed beta-blocker medications, which reduce the forcefulness and rate of cardiac contraction, lowering the outflow tract obstruction.

Your relative lack of symptoms is reassuring. Together with your cardiologist, carefully review the major risk factors for sudden death, which if present could indicate the need for an implantable cardioverter-defibrillator (ICD). Individuals with severe symptoms unresponsive to medical therapy may require heart surgery or a cath lab-based technique (alcohol septal ablation) to relieve the obstruction. Regarding inheritance, about half of all patients with HCM have genetic mutations which are known to cause the disease, and most of the others are likely to have variations that simply haven’t been discovered yet. Children have a 50 percent chance of getting the abnormal gene from their affected parent, in an inheritance pattern known as autosomal dominant. The Heart Failure Society of America suggests that the “most-affected” individual in a family with HCM—and that may be you—undergo genetic testing. If he or she has one of the known mutations, then their children should be tested. If positive for the mutation, the offspring’s symptoms and echo can be assessed every 3-5 years. If negative, they require no further workup for HCM.

Not long after my heart attack I was diagnosed with atrial fibrillation (a-fib). I really only notice symptoms at night. My doctor has suggested I undergo ablation, but I seem fine with medication (sotalol). What should I know about the risks and benefits of ablation, and is it safe to put it off for awhile?

It is important for patients to realize that anti-arrhythmic drugs (AAD’s) like sotalol are only useful for controlling symptoms. They do not reduce likelihood of stroke, and they do not prolong life. The only therapy proven to achieve those goals is anticoagulation with warfarin, one of the newer agents such as dabigatran, or in certain low-risk individuals, aspirin. From your description, you are tolerating the sotalol, and it has been rather effective at controlling your symptoms, so you would derive no clear benefits from pursuing a catheter-based ablation. This sophisticated procedure is most helpful for individuals with intermittent (paroxysmal) a-fib who do not tolerate AAD’s or experience symptom control with their use. The risk of a severe or life-threatening complication from ablation, including stroke, cardiac injury, and esophageal perforation, runs in the one to three percent range. Pending a change in your symptoms or new study results, it seems not only safe but prudent for you to hold off on ablation.

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