Manifestation of stenosis of the anterior interventricular branch of the left coronary artery: the Hiss beam legs blockade

The most common conduction disorder is right bundle branch block (RBBB). The prevalence of complete right bundle branch block (CRBBB) is 0.5—1.4%, and for incomplete RBBB, it is 0.6—4.7%. In some conditions, the CRBBB indicates a worsening of the prognosis. Objective. To compare the changes on the electrocardiogram as a sequential occurrence of a left anterior hemiblock and then a complete right bundle branch block with the results of coronary angiography to use this clinical case for prognostic purposes in other patients. Results. We present a clinical case of significant coronary stenosis with a bifascicular heart block in a 53-year-old patient without anginal pain with factors that increase the pre-test probability of coronary heart disease: hypertension, diabetes mellitus, gouty arthritis, 20 years history of smoking, and a sedentary lifestyle. The left anterior hemiblock was first identified on 09/09/20, CRBBB was diagnosed on the electrocardiogram on 06/15/24, and the intraventricular conduction disorder as a widening of the QRS complex increased over time (from 0.16 to 0.20 mm). It is known from the anatomy and physiology of the cardiac conduction system that both branches are supplied with blood from the left anterior descending artery (LADA). Coronary angiography showed 80% stenosis at the mouth of LADA. Stenoses of other arteries were not identified. The patient underwent LADA stenting. Conclusion. Cardiologists, internists, and general practitioners should pay special attention to all cases of a combination of complete right bundle branch block and anterior left bundle branch block, assess them for possible significant stenosis of the left anterior descending artery, and refer the patient to invasive coronary angiography. This approach helps to alter the course of the disease and improve the prognosis.