Coronary Ectasia and Ventricular Arrhythmia in a Patient With Prior Tick Exposure and Borrelia burgdorferi IgG Seroreactivity: A Case Report

Lyme borreliosis is a multisystem infectious disease caused by Borrelia burgdorferi and transmitted to humans through the bite of infected Ixodes ticks that most commonly affects the skin, joints, nervous system, and, less frequently, the heart. Lyme carditis typically presents with atrioventricular conduction abnormalities, whereas coronary vascular involvement is rarely described. We report a case of a 74-year-old man with exertional chest discomfort, dyspnea, and palpitations several months after an untreated tick bite. Electrocardiography demonstrated ventricular bigeminy with repolarization abnormalities, and 24-hour Holter monitoring showed a high burden of polymorphic premature ventricular complexes, with one episode of non-sustained ventricular tachycardia. Echocardiography demonstrated preserved left ventricular systolic function. Serological testing showed positive anti-B. burgdorferi IgG antibodies and negative IgM antibodies, consistent with prior exposure. Invasive coronary angiography revealed no obstructive epicardial coronary artery disease but demonstrated marked ectasia of the left anterior descending and right coronary arteries, both measuring up to 6.5 mm, with prolonged mural contrast retention. In the setting of exertional angina, persistent contrast retention within ectatic coronary segments, frequent ventricular ectopy, baseline bradycardia, and QTc prolongation, ranolazine was initiated as an antianginal therapy with potential antiarrhythmic benefit. At one-month follow-up, the patient reported marked improvement in symptoms. Repeat Holter monitoring showed a reduction in premature ventricular complexes to less than 5%, with no further episodes of non-sustained ventricular tachycardia. This case suggests that, in patients with coronary ectasia and a history compatible with prior untreated B. burgdorferi infection, Lyme-associated coronary vascular injury may be considered as a possible underlying mechanism, although definitive causality remains difficult to establish. Coronary ectasia with prolonged contrast retention should be recognized as a potential substrate for myocardial ischemia and ventricular arrhythmogenesis in patients without obstructive coronary artery disease. In selected patients with anginal symptoms and frequent ventricular ectopy, particularly when beta-blockers or conventional antiarrhythmic drugs are limited by bradycardia, QTc prolongation, or concern for conduction disease, ranolazine may offer a useful therapeutic option with combined antianginal and potential antiarrhythmic benefit.