Debra L. Beck and Eugene Braunwald, MD
Date Published: July 12, 2019
In 2016, the United States had 26,203 confirmed and 36,429 probable cases of Lyme disease (LD), a tick-borne bacterial infection. It is estimated, however, that the true incidence approaches 300,000 cases annually. Lyme disease incidence is also dramatically increasing in Canada, carried by migratory birds that are affected by climate change. In this review, Yeung and Baranchuk discuss the diagnosis and treatment of Lyme carditis, an early disseminated manifestation of Lyme disease infection (within 1 to 2 months with a range of 1 to 28 weeks).
The pathophysiology of Lyme carditis involves the direct myocardial invasion by bacteria and a subsequent immunologic and exaggerated inflammatory response. High-degree atrioventricular (AV) block is the most common presentation (90%), but it is usually transient in nature and resolves with antibiotic therapy.
Lyme carditis can also present as sinus node disease, intra-atrial block, atrial fibrillation, supraventricular tachycardia, sinus node dysfunction, bundle branch block, and ventricular tachycardia and fibrillation. Acute myocarditis, pericarditis, endocarditis, and pancarditis have also been reported.
Yeung and Baranchuk outline a systematic approach to the diagnosis of Lyme carditis in patients with high-degree AV block to facilitate timely identification and avoid unnecessary implantation of permanent pacemakers in otherwise healthy young individuals. Their Suspicious Index in Lyme Carditis (SILC) score can be associated with the mnemonic “CO-STAR”, standing for Constitution symptoms, Outdoor activity/endemic area, Sex, Tick bit, Age, and Rash.
Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine features a unique update program by Dr. Braunwald, creating a “living textbook” by featuring twice monthly updates including “Hot off the Press” and Late-Breaking Clinical Trials (links to authors’ presentation slides are also included).
Learn more about Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine, 11th Edition. Download a free chapter here.