Lyme disease is a complex of infections that are transmitted by deer ticks and other insects. It can cause general flu-like symptoms as well as joint and muscle pain. Neurological and cardiac symptoms occur in less then 10% of Lyme cases, usually when treatment is omitted or delayed (one month or more after the tick bite).
One bacteria involved in Lyme, Borrelia, can invade the heart muscle and cause a condition known as carditis, or infection of the heart tissues. If left untreated, it can cause heart block, which results when the electrical signal of the heart (that causes the heart to contract) gets interrupted. This can occur in varying degrees of severity, designated as first, second, and third degree heart block.
Third degree heart block, called atrioventricular block, is the most severe and may require the implantation of a pacemaker, which regulates the heartbeat and restores the normal function of the heart.
When the conduction of the heart’s electrical signal is not working properly, abnormal heart rhythms can occur. One of the most common is atrial fibrillation, in which the heart beats very fast and causes palpitations, dizziness, and difficulty breathing.
Atrial fibrillation is treated with medication to regulate the heartbeat and help the heart pump more efficiently. Blood-thinning medication is usually required also because blood can pool in the heart when the heart is pumping too fast. Clots that form in the heart can travel to the lungs, causing a pulmonary embolus, or to the brain, causing a stroke.
If a patient has pre-existing heart disease, a procedure called cardiac catheterization may be needed to open clogged arteries of the heart so blood flow to the heart is improved. Coronary artery bypass graft is a surgical procedure performed when multiple arteries are too clogged and must be repaired through “open heart” surgery.
If the heart valves (which separate the four chambers of the heart) are damaged through Lyme infection or preexisting heart disease, valve replacements can also be performed.
After cardiac surgery, it is recommended that patients participate in a cardiac rehabilitation program where the heart is monitored as patients engage in physical therapy exercises to strengthen the heart.
If heart function becomes impaired to the point where the heart does not pump enough blood to the rest of the body, congestive heart failure may occur. This is uncommon, as treatment with antibiotics usually prevents cardiac involvement. With congestive heart failure, blood flow backs up instead of going forward from the heart to the rest of the body. This can result in swelling in the lungs or body, mostly seen in the hands, abdomen, legs, or feet.
Treatment for congestive heart failure includes medications that help the heart to pump more efficiently and which help remove the extra fluid that accumulates in the body. Patients are instructed to monitor themselves for lung congestion, shortness of breath, swelling, and weight gain. Hospitalizations may be required if shortness of breath, excessive swelling, or increased weight gain occurs.
A low sodium diet is recommended for any type of heart disease because salt in the diet can cause fluid retention, which makes the heart work harder and increases blood pressure. Patients should use salt substitutes and avoid foods high in sodium, such as frozen prepared meals, deli meat, breakfast meat, fast food, and boxed or canned foods. A “heart-healthy” diet is recommended, which includes whole grains, fresh fruits and vegetables, and meats low in saturated fat (poultry, fish, and lean beef). Foods high in sugar and saturated fat should also be avoided.
Heart complications are uncommon (seen in less than 10% of Lyme cases) and can be avoided if Lyme disease is treated with effective antibiotics early, preferably within the first month. Not all cardiac complications result in congestive heart failure if treated promptly. If heart complications do occur, many times medications and a heart healthy diet are effective for helping patients to have a long and satisfactory quality of life.
If Lyme disease patients experience palpitations, dizziness, fainting, shortness of breath, or swelling of feet or hands, they should notify their physician so they can be evaluated for cardiac complications. Tests which might be used to determine the degree of cardiac involvement are lab work, electrocardiogram, echocardiogram, chest x-ray, and MRI. Sometimes a biopsy of the heart tissue is taken for evaluation. Treatment is based on the severity and degree of symptoms. Cardiac complications are rare and their potential should not be a source of anxiety for people who experience Lyme infection.