Junctional Arrhythmias
Junctional Arrhythmias - Related Videos
01:25
ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias
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2025
Arrhythmia is a condition characterized by an irregular heart rhythm, with ECG changes that differ based on its origin and nature. The types of arrhythmias discussed below include atrial, junctional, and ventricular arrhythmias.Atrial ArrhythmiasPremature Atrial Complexes (PACs): PACs are early atrial beats caused by stress, caffeine, alcohol, electrolyte imbalances, hypoxia, hyperthyroidism, or certain medications (e.g., bronchodilators and decongestants). The ECG shows early P waves with an...
03:18
Stimulation of the Intracardiac Nervous System to Assess Susceptibility to Arrhythmia
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2025
Source: Jungen, C., et al. Impact of Intracardiac Neurons on Cardiac Electrophysiology and Arrhythmogenesis in an Ex Vivo Langendorff System. J. Vis. Exp. (2018).The video demonstrates an ex vivo technique for stimulating the intracardiac nervous system to assess the heart’s susceptibility to arrhythmia. Using a perfusion apparatus, an isolated mouse heart is perfused with an oxygenated buffer. The intracardiac nervous system is then stimulated at a high frequency to induce arrhythmias.
01:16
ECG Interpretation of Arrhythmias I: Sinus Arrhythmias
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2025
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...
01:28
Mechanism of Cardiac Arrhythmias
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2024
Arrhythmias are irregular heart rhythms occurring when the heart's electrical impulses become abnormal. These disturbances can lead to various symptoms, depending on their severity and the underlying cause. Some common factors contributing to arrhythmias include hypoxia, ischemia, electrolyte imbalances, excessive catecholamine exposure, drug toxicity, and muscle overstretching. Arrhythmias can be classified into two main types based on the rate and site of origin of abnormal heart rhythms.
01:11
P-N junction
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2024
A p-n junction is formed when p-type and n-type semiconductor materials are joined together. At the interface of the p-n junction, holes from the p-side and electrons from the n-side begin to diffuse into the opposite sides due to the concentration gradient. This diffusion of carriers leads to a region around the junction where there are no free charge carriers, known as the depletion region. The charge density within the depletion region for the n-side and p-side can be described by the...
FAQs
Two mechanisms can allow the AV junction to control cardiac rhythm: increased automaticity within the junction or escape activity after sinus-node activity falls or impulse conduction is impaired. The distinction is clinically relevant because it connects the rhythm to either abnormal junctional impulse generation or a compensatory response to reduced upstream pacing.
Atrial activation may occur in an altered direction when the AV junction controls the rhythm. As a result, P waves can be absent, inverted, or retrograde, depending on how impulses travel through the atria. Their presence, polarity, and timing relative to ventricular depolarization help establish the relationship between atrial and ventricular activity.
A narrow QRS indicates that ventricular depolarization remains relatively preserved through the usual ventricular conduction pathway. When this pattern appears with abnormal or absent P waves, it supports assessment of a rhythm arising near the AV junction. The QRS pattern should still be interpreted together with rate and atrioventricular timing rather than in isolation.
Electrocardiographic evaluation focuses on three linked features: the rhythm rate, the QRS pattern, and the relationship between atrial and ventricular activity. Clinicians examine whether P waves are absent, inverted, or retrograde and determine how they align with ventricular complexes. This structured review helps separate related junctional patterns and identify abnormal conduction behavior.
These rhythms warrant attention when the clinical context suggests conduction disease, medication effects, or ischemia, because each may alter sinus-node activity, impulse conduction, or junctional automaticity. Recognizing the ECG pattern does not identify the cause by itself, but it directs evaluation toward these possible contributors and helps determine whether targeted management may be needed.
Recognition provides more than a rhythm label. ECG findings can show whether atrial activation is altered, whether ventricular depolarization remains narrow, and how atrial and ventricular activity are coordinated. Combined with the clinical context, these observations support evaluation of the underlying disturbance and help clinicians consider the need for targeted management.