In Lyme carditis, what is the most common objective manifestation observed?

In Lyme carditis, the most common objective manifestation observed is atrioventricular (AV) block. This condition arises as a result of Lyme disease, which is caused by the spirochete Borrelia burgdorferi transmitted through tick bites. The bacteria can affect the heart leading to inflammation of the conduction system, primarily manifesting as varying degrees of heart block, most notably first-degree AV block and higher degrees such as second-degree and complete heart block.

The presence of AV block is an important clinical finding, as it indicates a specific involvement of the cardiac conduction system due to Lyme borreliosis. This arrhythmia can become symptomatic, potentially presenting with dizziness, palpitations, or syncope, depending on the severity of the heart block and the individual patient's response.

While skin rashes, such as erythema migrans, are characteristic of Lyme disease and can appear early in the disease course, they are subjective findings and often visible upon examination but do not reflect the systemic implications that cardiac manifestations like AV block do. Severe headache can occur with Lyme disease but is not a direct manifestation of carditis. Joint pain is also common in Lyme disease, particularly in later stages, but again, it is subjective and lacks the