The spectrum of collagen fibre abnormalities known to occur in EDS can result in occasional cardiac problems. Usually these are benign and have minimal impact on an individual's lifestyle but may require on-going non-invasive monitoring and outpatient review.
Mitral valve leaﬂet prolapse
The most common of these abnormalities is mitral valve leaﬂet prolapse. This abnormality is also seen in the normal population but is more common in people with collagen tissue disorders. Almost certainly the abnormal microstructure of collagen fibres in the valve leaﬂet underlies the cause of the abnormality. The valve leaﬂet has a structure rather like that of a sail on a yacht. If the material that is used to make a sail is slightly defective then over time and exposure to the wind the sail may stretch and give in places. Analogously in an individual with EDS, following exposure to high pressure pumping by the heart, part of the mitral valve can stretch and deform. Most often, curiously, this stretching occurs just in one place resulting in a characteristic 'parachute deformity'. The resultant leak is usually very well tolerated by the main pumping chamber of the heart which grows and adapts to cope with the increased work it has to do. Unless severe the leak does not need any sort of intervention. If the valve does leak severely then surgical repair of the valve or, if this is not possible, replacement by an artificial valve may be required.
Previously it was advised that individuals with leaking valves should receive antibiotics at the time of dental work to stop the valve getting infected. More recently it has been realised that the risk of infection is so low that antibiotic 'prophylaxis' actually is not required in this situation.
Aortic root dilation
The other well recognised but much rarer complication of EDS is that of aortic root dilation. Again because of slightly weaker collagen fibres the lower parts of the aortic root can be prone to stretching and widening. The aorta is a large diameter pipe that receives all the blood coming out of the heart carrying it to the rest of the body via its arterial branches. Self-evidently this structure is vitally important. Once again, if collagen fibres are slightly defective the overall strength of this pipe is lessened. As a result in individuals with Ehlers-Danlos syndrome it can be prone to stretching. If it starts to stretch beyond a certain point it can be prone to splitting (dissection) and rupturing which can be extremely dangerous. Not only this but stretching of this structure can cause another important heart valve, the aortic valve, to leak. Surgical operations may be required to repair or replace the stretched segment of aorta and to repair or, more commonly, replace the aortic valve. Sometimes these operations have to be done as an emergency, again increasing the risk to the patient.
Should I be concerned?
It should be emphasised however that cardiac surgical operations (especially aortic root replacement operations) are rare and the chances of any one individual requiring them is very low. Reassuringly the structure of both the mitral valve and aortic root can be monitored very easily and non-invasively using an ultrasound scanner (echo). If serial ultrasound scans undertaken over a period of years remain unchanged then there is very little to be concerned about. As a result, from the cardiac point of view, normal physical and sporting activity is not contraindicated for individuals with no or only minor and stable structural abnormalities on ultrasound. Clearly if more important abnormality is detected then review by a cardiologist is required.
Postural orthostatic tachycardia syndrome
In the recent past an association has been noted between EDS and an unusual but benign condition called Postural Orthostatic Tachycardia Syndrome (POTS). POTS is common in younger individuals especially in teenagers and people in their early twenties. The individual is aware of an unusual increase in heart rate on moving from a lying to a standing position, which can on occasion be quite debilitating. It is important to emphasise that the heart remains in its normal rhythm but that the rate increases inappropriately rapidly in response to the postural change. This inappropriately fast heart rate can be exacerbated by dehydration or concomitant illness. The causes of this condition, and the reason for it to be associated with EDS are both unknown. Symptoms can be minimised by keeping well hydrated and maintaining salt intake, avoiding hot baths or showers and sudden postural changes. Symptoms tend to resolve over time.
The views expressed are those of the author(s) and should not be construed to represent the opinions or policy of the Ehlers-Danlos Support UK or its Trustees