Related Experiment Video
Updated: Sep 12, 2026

A New Single Chamber Implantable Defibrillator with Atrial Sensing: A Practical Demonstration of Sensing and Ease of Implantation
Published on: February 28, 2012
Apparent pacemaker malfunction due to ventricular blanking
Abstract:
Electrocardiographic interpretation in patients with dual chamber pacemakers requires an intimate understanding of their manner of functioning. This report describes a patient whose pacemaker was suspected of malfunction because of failure to sense premature beats. This sense-failure resulted from the fortuitous concurrence of the sensed portion of the premature beat with the ventricular blanking period and was resolved by reducing the low rate limit of the pacemaker. Three principles must be recognized in interpreting suspected failure of sensing: 1. The channel of origin of the pacing artifact must be identified. 2. The surface QRS morphology does not necessarily correspond to the signal detected by the pacemaker. 3. Failure to sense does not necessarily equal pacemaker malfunction.
More Related Videos
06:57Ablation of Ischemic Ventricular Tachycardia Using a Multipolar Catheter and 3-dimensional Mapping System for High-density Electro-anatomical Reconstruction
Published on: January 31, 2019
10:17Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System
Published on: April 11, 2025
Related Concept Videos
The Cardiac Cycle
The Process
Electrical signals—sent from the sinoatrial (SA) node in the right atrial wall to the atrioventricular (AV) node between the right atrium and right ventricle—cause both atria to simultaneously contract. When the signal reaches the AV node, it pauses for approximately a tenth of a second, allowing the atria to contract and empty blood into the...
Electrophysiology of Normal Cardiac Rhythm
Disturbances in Heart Rhythm
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
Cardiac 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
Dysrhythmias IV: Characteristics of Bradyarrhythmias
ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias