Deer ticks transmit the bacterium Borrelia burgdorferi that is responsible for causing Lyme disease. According to the "Journal of Invasive Cardiology," “an estimated 4 to 10 percent of all patients in the United States with untreated Lyme disease develop Lyme carditis.” The principal cardiac symptom involves conduction defects. Pericarditis and myocarditis can occur as well.
Heart Block
The Canadian Lyme Disease Foundation states that cardiac symptoms associated with Lyme disease present 21 days after exposure. People who exhibit cardiac symptoms with no other cardiac risk factors should be screened for Lyme disease. The incidence of Lyme carditis is increasing and manifests with varying degrees of atrioventricular or AV block.
AV block caused by Lyme disease is treatable and generally reversible. The Merck Manual defines heart block as a delay in the conduction of an electrical impulse once it passes through the AV node and the bundle branches which are located between the atria and ventricles of the heart. Heart block is divided into three groups, including first degree, second degree and complete heart block. The degrees signify the extent of delay in conduction. A slower heart rate and an irregular heart rate are signs of heart block. Complete heart block is the most serious arrhythmia commonly causing fatigue, dizziness and fainting.
Pericarditis
The Johns Hopkins Arthritis Center lists pericarditis as a cardiac symptom occurring in 4 to 10 percent of midterm manifestations of Lyme disease. Later manifestations, such as cardiac involvement, present weeks to months following exposure. Pericarditis is inflammation of the pericardium, which is a two layer sac that surrounds the heart. Sharp chest pain is a symptom caused by the two irritated layers rubbing against each other. The MayoClinic.com includes shortness of breath when reclining, fatigue, low-grade fever, dry cough and swelling in the legs and abdomen as additional symptoms of pericarditis.
Myocarditis
Acute myocarditis is a rare complication of Lyme disease. Myocarditis is the inflammation of the heart muscle. It directly impacts the heart’s strength to pump blood normally. The MayoClinic.com lists symptoms as fast or irregular heart rate, chest pain, shortness of breath, fatigue and fluid retention in the legs, ankles and feet.
