Lyme Carditis Explained: What You Need to Know

Echocardiography & Lyme Disease

What is Lyme Disease?

This illness is spread by black-legged ticks, also known as the American dog tick, a small parasitic bug primarily found in the northeastern, north-central, and Pacific coastal regions of the United States. They thrive in areas of high humidity and ample vegetation and are known to transmit bacteria, viruses, and parasites that cause disease in humans.

Ticks feed on the blood of mammals, birds, reptiles, and amphibians and can pass on the bacteria, borrelia burgdorferi, to the host. Their bites can cause irritation and pose concerns for both humans and veterinarians alike. According to the Center for Disease Control, about 5-10% of patients with Lyme disease have prolonged symptoms such as ongoing fatigue, muscle pain, or cognitive difficulties (CDC, 2024).

Cardiac Involvement

When borrelia burgdorferi enters myocardial tissues, it can affect the heart’s conduction system and result in varying degrees of heart block. Electrical signals are unable to reach the ventricles, which can contribute to bradycardia and ectopy.

In this lesson, we will share a case of lyme carditis and discuss the echocardiographic analysis.

The Parasternal View

Normally, the sinoatrial node generates an electrical signal that causes the atria (upper chambers) to contract. The impulse then travels through the atrioventricular node to the ventricles (lower chambers) so that they can contract. In cases of heart block, the electrical signals make it to the ventricles at a slower rate, only some of the time, or not at all. These translate into the different types of heart block. The following case example discusses the echocardiographic findings associated with lyme carditis and how to assess it like an expert.