Related Experiment Video
Updated: Jul 12, 2026
09:20
Microelectrode Array Recording of Sinoatrial Node Firing Rate to Identify Intrinsic Cardiac Pacemaking Defects in Mice
Published on: July 5, 2021
The total absence of atrial automaticity in a child with sinus node dysfunction
Fabrizio Drago1, Giovanni Fazio, Alfredo Di Pino
1Arrhythmias Service, Pediatric Cardiology Department, Bambino Gesù Hospital, Rome, Italy. drago@OPBG.net
Nature Clinical Practice. Cardiovascular Medicine
|August 23, 2007
Summary
A 9-year-old child experienced alternating heart rhythms, diagnosed as sinus node dysfunction. This condition affected heart rate response during exercise, leading to postponed pacemaker implantation.
Area of Science:
- Pediatric Cardiology
- Electrophysiology
- Cardiac Arrhythmias
Background:
- A 9-year-old child presented with an unusual heart rhythm during a sports evaluation.
- The child exhibited alternating junctional and idioventricular rhythms, with P waves absent during exercise testing.
Observation:
- Exercise testing revealed a blunted heart rate increase and normal atrioventricular conduction.
- Atrial pacing confirmed normal conduction but a prolonged recovery time for the ectopic rhythm.
Findings:
- Three-dimensional electrophysiological mapping identified 1:1 retrograde homogeneous conduction through the right atrium.
- The diagnosis was sinus node dysfunction, characterized by abnormal heart rhythm regulation.
Implications:
- Pacemaker implantation was deferred, suggesting a conservative management approach in this pediatric case.
- Understanding retrograde conduction is crucial for managing complex pediatric arrhythmias.
More Related Videos
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...
01:16ECG 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...
01:19Conduction System of the Heart
Autorhythmicity is a term that refers to the heart's inherent ability to generate electrical signals and instigate muscle contractions. This self-regulating conduction system within the heart consists of two key components: the pacemaker cells and specialized conducting cells.
The pacemaker cells are located in two primary nodes: the sinoatrial (SA) node and the atrioventricular (AV) node. The SA node pacemaker cells can autonomously depolarize, triggering an action potential that leads to the...
The pacemaker cells are located in two primary nodes: the sinoatrial (SA) node and the atrioventricular (AV) node. The SA node pacemaker cells can autonomously depolarize, triggering an action potential that leads to the...
01:20Conduction System of the Heart
The cardiac conduction system produces and transmits electrical impulses that prompt myocardial contraction, ensuring efficient heart function. This intricate system ensures that the heart beats in a coordinated and efficient manner, beginning with the atria and then the ventricles. The conduction system optimizes cardiac output by maintaining this precise sequence, which is crucial for adequate blood circulation.
This system relies on the unique properties of nodal and Purkinje cells:...
This system relies on the unique properties of nodal and Purkinje cells:...
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...
01:29Dysrhythmias 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.