Related Experiment Video
Updated: Jun 21, 2026
12:45
Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
The rate dependent bundle branch block -- transition from left bundle branch block to intraoperative normal sinus
Seema Mishra1, Prashant Nasa, Gaurav Nirwani Goyal
1Unit of Anesthesiology, Institute Rotary Cancer Hospital (IRCH), Ansari Nagar, New Delhi, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India. mseema17@yahoo.co.in
Middle East Journal of Anaesthesiology
|July 9, 2009
Summary
A rare case of intermittent left bundle branch block (LBBB) in a hypertensive patient under anesthesia resolved spontaneously. Further cardiac risk evaluation is recommended beyond ECG findings alone.
Area of Science:
- Cardiology
- Anesthesiology
- Cardiac Electrophysiology
Background:
- A chronic hypertensive patient presented with left bundle branch block (LBBB) on electrocardiogram (ECG).
- The patient underwent general anesthesia for a right modified radical mastectomy.
- Hypertension is a known comorbidity associated with cardiac conditions.
Observation:
- Intermittent reversion of LBBB to normal sinus rhythm was observed during the peri-operative period.
- This phenomenon of rate-dependent LBBB is considered a rare clinical entity.
- The patient's ECG findings were dynamic under anesthesia.
Findings:
- The intermittent LBBB was transient and resolved spontaneously.
- Rate dependency was suggested as a potential mechanism for the LBBB's intermittent nature.
- The patient's underlying cardiac status required further assessment.
Implications:
- Relying solely on ECG findings for risk evaluation in patients with LBBB during anesthesia is insufficient.
- Comprehensive cardiac risk assessment is crucial for patients with LBBB undergoing surgery.
- Further investigations are warranted to determine the underlying cause and management of intermittent LBBB in surgical patients.
Related Concept Videos
01:18Dysrhythmias IV: Characteristics of Bradyarrhythmias
Bradyarrhythmias are cardiac rhythm disorders characterized by a slower-than-normal heart rate, typically defined as fewer than 60 beats per minute. Some of which are discussed here:Sinus BradycardiaSinus bradycardia presents a heart rate lower than 60 beats per minute, with a regular rhythm originating from the SA node. The ECG typically shows normal P waves preceding each QRS complex, a normal PR interval (0.12 to 0.20 seconds), and a normal QRS duration (0.06 to 0.10 seconds).First-Degree AV...
01:15Dysrhythmias I: Introduction
Dysrhythmias refers to abnormalities in the heart's rhythm. They result from disruptions in the heart's electrical conduction system, which includes the sinoatrial(SA)node, atrioventricular(AV) node, the bundle of His, bundle branches, and Purkinje fibers.Definition and PathophysiologyDysrhythmias result from disorders of impulse formation, impulse conduction, or both. The heart contains specialized cells in the sinoatrial node, atrioventricular node, and the bundle of His and Purkinje fibers...
01:19Electrophysiology of Normal Cardiac Rhythm
The normal cardiac rhythm is a synchronized electrical activity that facilitates the regular and coordinated contraction of the heart muscle. This process is essential for efficient blood circulation throughout the body. The fundamental elements involved in establishing and maintaining this rhythm include the unique electrical properties of cardiac muscle cells, the sinoatrial (SA) node's pacemaker function, the specialized conducting system, and the ionic mechanisms underlying each phase of...
01:19Depolarizing Blockers: Pharmocokinetics
Depolarizing blockers are administered through intravenous injection. Succinylcholine is the most common choice of depolarizing blockers in emergency clinical practices. Although they have a rapid onset, they readily diffuse away from the motor end plate into the extracellular fluid. They are metabolized by enzymes such as liver butyrylcholinesterase and plasma pseudocholinesterases. This produces a short duration of action, typically 5-10 minutes long, unlike nondepolarizing blockers, which...
01:16ECG Interpretation of Arrhythmias I: Sinus Arrhythmias
Arrhythmias are disturbances in the heart's rhythm that lead to abnormal heartbeats. These irregularities can originate from different parts of the heart and are classified based on their origin and nature.
Types of Arrhythmias
Sinus Node Arrhythmias
Sinus Bradycardia: Originating from the sinoatrial (SA) node, sinus bradycardia involves slower impulses, resulting in a heart rate of less than 60 beats per minute (bpm). Causes include sleep, vagal stimulation, beta-blockers, hypothyroidism, and...
Types of Arrhythmias
Sinus Node Arrhythmias
Sinus Bradycardia: Originating from the sinoatrial (SA) node, sinus bradycardia involves slower impulses, resulting in a heart rate of less than 60 beats per minute (bpm). Causes include sleep, vagal stimulation, beta-blockers, hypothyroidism, and...
01:29Dysrhythmias III: Characteristics of Dysrhythmias
Dysrhythmias, also known as arrhythmias, are irregular heart rhythms that result from abnormal electrical activity in the heart, affecting its ability to circulate blood efficiently. Tachyarrhythmias, a subset of dysrhythmias, are characterized by abnormally fast heart rates exceeding 100 beats per minute. Here are some types of tachyarrhythmias with their distinct ECG features:Sinus Tachycardia:Sinus tachycardia presents a regular heart rhythm with an increased rate of 101-180 beats per minute.