Heart (valve) Disease

Heart disease is common in patients living with MPS I – Hurler disease. Medications are available to help manage the heart problems that occur as a result of MPS I. Cardiomyopathy (weak heart muscle) and endocardial fibroelastosis (scarred and stiff heart) are conditions that can occur in severely affected young people. Coronary artery disease caused by GAG storage in the heart blood vessels is like the coronary artery disease experienced by older people and can lead to death.

Most people with MPS I, including people living with Scheie disease, may develop problems with their heart valves. Eventually the damaged heart valves may need to be replaced surgically. The doctor may hear heart murmurs (sounds caused by turbulence in blood flow in the heart) if the valves become damaged by stored GAG. The heart valves are designed to close tightly in order to stop blood from flowing back in the wrong direction as blood passes from one chamber of the heart to another. If a valve is weakened, it may not shut firmly enough and a small amount of blood may shoot backwards, leading to turbulence and a murmur. A doctor may refer to this backward flow of blood due to a faulty heart valve as “regurgitation”. Conditions that involve regurgitation include mitral valve regurgitation (where the valve within the left side of the heart does not shut firmly enough) and aortic valve regurgitation (where the valve between the left side of the heart and the rest of the body does not shut firmly enough).

Images courtesy of the National MPS Society

Since heart problems occur so frequently in MPS I, individuals with MPS I often have a test known as an echocardiogram regularly (as determined by your doctor) to show whether any problems are beginning. The test is similar to the ultrasound screening of babies in the womb. It can identify problems with the heart muscle, heart function, and heart valves but, like many tests, it cannot detect all possible problems.

In people who are severely affected, the muscle of the heart may be weakened by storage of GAG, and the heart may also be under strain by having to pump blood through abnormal lungs. A number of affected individuals have high blood pressure. Occasionally, the coronary arteries of severely affected people may become narrowed and cause episodes of chest pain (angina). If a person with MPS I notices these symptoms, they should consult their doctor.