Episodic Left Bundle Branch Block-A Comprehensive Review of the Literature

Unmasking Coronary Artery Disease With Intermittent Left Bundle Branch Block: A Case Report

Intermittent left bundle branch block (LBBB) is an unusual phenomenon, with very few cases documented in the literature. It is often considered a reflection of underlying conditions known to increase the risk of cardiovascular morbidity and death, including coronary artery disease (CAD), cardiomyopathy, hypertensive heart disease, and aortic valve disease. In rare instances, coronary vasospasm is the sole underlying condition. It is typically diagnosed by ECG and managed according to the underlying cause. We describe a case of intermittent LBBB presenting with chest pain. The ECG showed dynamic changes with transient/intermittent LBBB. An angiogram was performed, revealing significant coronary lesions. The patient was eventually managed conservatively and discharged on dual antiplatelet therapy for a duration of one year with a one-month clinic follow-up where his condition improved. Intermittent LBBB represents a transient disturbance in the intraventricular conduction system, where diseased conduction occurs secondary to an underlying cause, but normal conduction eventually restores. This results in complexes where LBBB appears alongside normally conducted beats in a single ECG tracing. There is limited knowledge about the prognosis of patients with intermittent LBBB; therefore, patients with LBBB should undergo careful evaluation due to the known association with serious cardiac pathologies, particularly cardiac ischemia. It is important to consider the potential adverse effects on ventricular function.

New-Onset Intermittent Deceleration-Dependent Left Bundle Branch Block Following Induction of General Anesthesia in a Healthy Patient: A Case Report

This case report aims to highlight an atypical presentation of deceleration-dependent aberrancy (DDA) following the induction of general anesthesia in a patient with no known cardiac history. It emphasizes the critical role of intraoperative monitoring and the potential effects of anesthetic agents on the cardiac conduction system. A 46-year-old Hispanic male with no significant past medical or surgical history presented for surgical repair of a comminuted radial fracture. Following anesthesia induction with propofol, midazolam, and fentanyl, he developed a transient left bundle branch block (LBBB) exhibiting deceleration-dependent characteristics. Despite stable hemodynamics, the LBBB pattern appeared at heart rates below 60 beats per minute and resolved with heart rates above 90 beats per minute. This was managed intraoperatively with glycopyrrolate. Postoperative evaluations, including a 12-lead ECG, echocardiogram, and nuclear stress test, indicated normal biventricular function with a small to moderate reversible perfusion defect. The patient did not report cardiac symptoms postoperatively and did not prefer to undergo a coronary angiogram. This report underscores the importance of recognizing rate-dependent LBBB as a potential intraoperative complication, even in patients without pre-existing cardiac conditions. The transient nature of DDA, influenced by anesthetic agents and managed through careful monitoring and pharmacological intervention, highlights the necessity for vigilance in perioperative settings. This case contributes to a growing body of evidence suggesting that anesthetic management may require tailored approaches for patients experiencing or at risk for conduction abnormalities. This case illustrates the complexities of cardiac conduction disturbances such as DDA in the context of general anesthesia, serving as a reminder of the importance of thorough monitoring and the judicious use of rate-modifying drugs. It fosters a deeper understanding of the interaction between anesthesia and cardiac electrophysiology. Further research is needed to explore the mechanisms and management strategies for anesthetic-related cardiac conduction abnormalities.

Chest Pain With Exercise-Induced Left Bundle-Branch Block-Is There a Connection?

This case report describes a patient in their early 60s with chest pain during exertion.

Left Bundle Branch Block: Characterization, Definitions, and Recent Insights into Conduction System Physiology

Left bundle branch block (LBBB) is not just a simple electrocardiogram alteration. The intricacies of this general terminology go beyond simple conduction block. This review puts together current knowledge on the historical concept of LBBB, clinical significance, and recent insights into the pathophysiology of human LBBB. LBBB is an entity that affects patient diagnosis (primary conduction disease, secondary to underlying pathology or iatrogenic), treatment (cardiac resynchronization therapy or conduction system pacing for heart failure), and prognosis. Recruiting the left bundle branch with conduction system pacing depends on the complex interaction between anatomy, site of pathophysiology, and delivery tools.

Non-ischemic Painful Intermittent Left Bundle Branch Block With Infra-Hisian Block Treated Successfully With Biventricular Pacemaker: A Case Report and Literature Review

Non-ischemic painful left bundle branch block (LBBB) is defined as chest pain that occurs simultaneously with the appearance of left bundle branch block and resolves with the disappearance of the left bundle branch block in patients without evidence of myocardial ischemia. The underlying mechanism of this rare clinical occurrence has not been fully understood, but it has been proposed that it results from ventricular dyssynchrony. In this case report, we present a 65-year-old male with non-ischemic chest pain who was found to have intermittent left bundle branch block (ILBBB) with infra-Hisian conduction delay, treated successfully with a biventricular pacemaker. After excluding the presence of angiographic coronary artery disease, an electrophysiology study was conducted to direct the management and investigate other causes of chest pain. The present study highlights the importance of obtaining electrophysiology studies in patients with painful left bundle branch block with no angiographic evidence of coronary artery disease to diagnose this uncommon syndrome.

Transient Left Bundle Branch Block in the Setting of Cardiogenic Pulmonary Edema

Cardiogenic pulmonary edema complicated by transient left bundle branch block (LBBB) is a relatively rare finding. We report a case of a 52-year-old woman with underlying heart failure but no structural heart disease who was referred for evaluation due to severe shortness of breath and documented LBBB on a 12-lead EKG. She was diagnosed with cardiogenic pulmonary edema due to medication noncompliance. With the resolution of her symptoms by treating her pulmonary edema with bisoprolol and furosemide, repeated EKG showed resolution of LBBB. A review of her medical records showed similar presentations of pulmonary edema associated with transient LBBB. In conclusion, to the best of our knowledge, transient LBBB associated with cardiogenic pulmonary edema is very uncommon. The etiology of transient LBBB remains unclear, however, the most likely theory that explains our patient's transient LBBB is a consequence of ventricular enlargement from fluid overload and cardiac muscle strain with dilatation, causing bundle conduction interruption. Our patient's cardiogenic pulmonary edema was complicated with transient LBBB in multiple previous presentations with a resolution of the LBBB after treating the underlying pulmonary edema.

Left Bundle Branch Block: Characterization, Definitions, and Recent Insights into Conduction System Physiology

Left bundle branch block (LBBB) is not just a simple electrocardiogram alteration. The intricacies of this general terminology go beyond simple conduction block. This review puts together current knowledge on the historical concept of LBBB, clinical significance, and recent insights into the pathophysiology of human LBBB. LBBB is an entity that affects patient diagnosis (primary conduction disease, secondary to underlying pathology or iatrogenic), treatment (cardiac resynchronization therapy or conduction system pacing for heart failure), and prognosis. Recruiting the left bundle branch with conduction system pacing depends on the complex interaction between anatomy, site of pathophysiology, and delivery tools.

Intermittent left bundle branch block and acute heart failure in trastuzumab-induced cardiotoxicity

A 70-year-old woman with HER2+/ER+ breast cancer on adjuvant trastuzumab therapy without a history of cardiovascular disease presented with respiratory failure from influenza and was found to have intermittent left bundle branch block (LBBB) with new onset systolic heart failure. Her course was complicated by polymorphic ventricular tachycardia and recurrent chest pain. Significant investigations included a normal cardiac MRI and cardiac catheterisation with unobstructed coronaries. It was determined that the aetiology of her heart failure was trastuzumab-induced cardiotoxicity after comprehensive workup. This case highlights an uncommon presentation of LBBB and the steps taken to diagnose a rare cardiomyopathy.

Transient left bundle branch block and intraventricular dyssynchrony as a cause of reversible left ventricular dysfunction: The "in vivo" documentation of spontaneous electrical remodeling

Spontaneous resolution of non-rate-dependent left bundle branch block (LBBB) has been rarely reported. We present the case of a 74-year-old woman admitted with pulmonary edema, a newly diagnosed LBBB and severe left ventricular (LV) dysfunction. Five months later, the patient was asymptomatic, the ECG recording showed complete regression of the LBBB to narrow QRS and LV function completely recovered. However, at one-year follow-up LBBB reappeared together with mild LV dysfunction. Spontaneous resolution of LBBB may be responsible for LV electrical and mechanical reverse remodeling in dyssynchronopathies.

Is It Complete Left Bundle Branch Block? Just Ablate the Right Bundle

Complete left bundle branch block (LBBB) is established according to standard electrocardiographic criteria. However, functional LBBB may be rate-dependent or can perpetuate during tachycardia due to repetitive concealed retrograde penetration of impulses through the contralateral bundle "linking phenomenon." In this brief article, we present two patients with basal complete LBBB in whom ablating the right bundle unmasked the actual antegrade conduction capabilities of the left bundle. These cases highlight intriguing overlap between electrophysiological concepts of complete block, linking, extremely slow, and concealed conduction.