Wenckebach pattern in right bundle branch block - benign or not?
Weiting Huang1, Paul Chun Yih Lim1, Chi-Keong Ching1
1National Heart Centre of Singapore, Singapore.
Abstract:
A Mobitz type I block (Wenckebach phenomenon) with narrow QRS complex is almost always due to a lesion in the AV node. In a type I block with wide QRS complex (>0.12sec), the block can be in the His-Purkinje system in 60-70% of the cases. Even though the progressive PR prolongation with every conducted beat suggests Wenckebach phenomenon, one needs to pay attention to the accompanying QRS complex. In the setting of persistent right bundle branch block, axis change of subsequent conducted beat before an unconducted p suggests alternating fascicular block, giving clue to unreliable infra-Hisian conduction; and in the setting of symptoms, a pacemaker should be implanted. Infra-Hisian Wenckebach block is rare with only sparse literature reports. The present case report adds to these, suggesting that wide QRS with Wenckebach block on surface ECG may indicate infra-Hisian conduction abnormalities.
Related Concept Videos
01:18Dysrhythmias IV: Characteristics of Bradyarrhythmias
01:30Cardiac Action Potential
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials
01:28Electrocardiogram Fundamentals
An electrocardiogram (ECG) is a diagnostic tool for identifying cardiac conditions such as arrhythmias, conduction abnormalities, and myocardial ischemia.
Definition
An electrocardiogram (ECG) visualizes the heart's electrical activity by tracing the electrical movement associated with each heartbeat on a graph or monitor. As the heart beats, an electrical wave passes through it, correlating with the cardiac cycle events.
Parts of an ECG
An ECG utilizes electrodes on the skin...
01:25Correlation between ECG and Cardiac Cycle
A cardiac action potential originates in the SA node and spreads throughout the atria and the AV node in approximately 0.03 seconds. This results in the P wave in an ECG and triggers atrial contraction. The action potential is then briefly slowed at the AV node, allowing the atria to contract and fill the ventricles with blood before...
01:29Disturbances in Heart Rhythm
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
01:29Dysrhythmias III: Characteristics of Dysrhythmias