Abstract
BACKGROUND: Excessive prolongation of the PR interval indicates the potential for atrioventricular (AV) asynchrony, resulting in severe impairment of cardiac function. CASE PRESENTATION: A 72-year-old man presented to the cardiology department with a history of worsening shortness of breath and chest tightness over the past 3 years. The electrocardiogram (ECG) showed sinus rhythm with a prolonged PR interval of 400 ms. The echocardiogram revealed mild mitral valve regurgitation with mitral E-A fusion during ventricular diastole. The patient received left bundle branch area pacing to shorten the AV conduction time. CONCLUSION: In patients with symptomatic AV block, reflected by an excessively prolonged PR interval, prompt decision-making regarding cardiac pacing therapy can help relieve clinical symptoms and enhance the patient's quality of life.