Surgery ups survival with common heart ailment
People with an enlargement of the heart walls that obstructs the flow of blood can expect to live longer after undergoing a surgical procedure to ease the condition, a study shows.
The disorder - hypertrophic cardiomyopathy (HCM) - is a leading cause of sudden death in young people. However, after the operation their risk of dying is pretty much in line with that of the general population, according to the newly reported findings.
HCM affects more than 500,000 Americans, so it’s actually more common than better-known conditions such as Crohn’s Disease or multiple sclerosis. HCM involves a thickening of the heart muscle walls, particularly the wall (or septum) that separates the two main pumping chambers.
That thickening can affect blood flow into and out of the heart, which may lead to symptoms such as shortness of breath, chest pain, dizziness, palpitations, or fainting after exertion. HCM can cause sudden death by sending the heart into a dangerous electrical rhythm and is the most common cause of death during athletic competition.
The primary cause of HCM seems to be genetic. About half of affected patients have a close relative with the disease.
Hypertrophic cardiomyopathy Definition
Hypertrophic cardiomyopathy (HCM) is a form of cardiomyopathy (disease of the heart muscle) involving thickening of the heart muscle. This interferes with the function of the heart.
Treatments may include medications such as beta-blockers to slow the heart’s contractions, and placement of an internal defibrillator to shock the heart back into normal rhythm. For patients with severe blood-flow obstruction whose symptoms don’t respond to medications, a surgical procedure - myectomy - which removes a portion of the thickened muscle wall, provides excellent symptom relief.
“The improvement in symptoms for myectomy patients has been well documented,” said Dr. Steve R. Ommen, a cardiologist at the Rochester, Minnesota-based Mayo Clinic College of Medicine, who led the current study. But “until now, we didn’t know whether feeling better translated into living longer.”
Hypertrophic cardiomyopathy Causes, incidence, and risk factors
In this condition, heart muscle becomes too thick to function properly. The thickening is often not symetrical, affecting one part of the heart more than others. It may interfere with the functioning of the heart by reducing the size of the ventricular chamber. It may also reduce the ability of the valves to work properly. The thickening of the heart muscle may, in some circumstances, obstruct the flow of blood out of the heart.
In addition, heart cells become tangled and jumbled up instead of maintaining their normal pattern. One consequence of the disarray of these cells is that the electrical impulses that normally run though the heart muscle cannot proceed normally, which can lead to abnormal heart rhythms (arrhythmias).
HCM is usually an inherited disorder, the consequence of several defects in the genes controlling heart muscle growth. The abnormal muscle growth usually occurs during periods of a person’s rapid general growth, typically during adolescence.
Younger people are likely to have a more severe form of the disease, but HCM may be diagnosed in people of all ages. HCM among people over 60 years of age is often associated with mild hypertension (High Blood Pressure).
As they report in the Journal of the American College of Cardiology, Ommen and colleagues evaluated the impact of myectomy on the survival of 1337 HCM patients who comprised three subgroups: 289 patients surgically treated for obstructive HCM; 228 patients medically treated for obstructive HCM; and 820 patients with non-obstructive HCM who did not need the operation.
According to the team, overall survival rates of the myectomy group at 1, 5, and 10 years after surgery were 98 percent, 96 percent, and 83 percent, respectively. Moreover, these rates did not differ from those in the US general population matched for age and gender, or in patients with non-obstructive HCM.
The group with HCM managed with medical treatment did not fare as well as the surgery group.
Based on the findings, Ommen concluded that “patients with severe symptoms related to HCM can now be counseled that surgical myectomy, a time-proven operation with low complication rates, can be expected to markedly improve symptoms and afford normal longevity.”
SOURCE: Journal of the American College of Cardiology, August 2, 2005.
Revision date: July 6, 2011
Last revised: by Andrew G. Epstein, M.D.