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Related Concept Videos

Disturbances in Heart Rhythm01:28

Disturbances in Heart Rhythm

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Arrhythmia or dysrhythmia refers to an abnormal heart rhythm caused by a defect in the heart's conduction system. It can cause the heart to beat irregularly, too quickly, or too slowly, leading to symptoms like chest pain, shortness of breath, and fainting. Factors such as stress, caffeine, alcohol, nicotine, cocaine, certain drugs, congenital defects, diseases, and electrolyte abnormalities can trigger arrhythmias.
Arrhythmias are categorized by their speed, rhythm, and origin. A slow...
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Mechanism of Cardiac Arrhythmias01:28

Mechanism of Cardiac Arrhythmias

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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.
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ECG Interpretation of Arrhythmias I: Sinus Arrhythmias01:16

ECG Interpretation of Arrhythmias I: Sinus Arrhythmias

195
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,...
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Cardiac Cycle01:29

Cardiac Cycle

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The cardiac cycle refers to the sequence of events that occur in the heart from the beginning of one heartbeat to the next. It's characterized by alternating periods of contraction (systole) and relaxation (diastole) of the heart muscles.
During the cardiac cycle, blood flow through the heart is regulated entirely by changing pressure gradients. This sequence of events begins with the heart in a state of total relaxation, known as mid-to-late diastole, during which blood passively flows from...
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Conduction System of the Heart01:19

Conduction System of the Heart

4.8K
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...
4.8K
Correlation between ECG and Cardiac Cycle01:25

Correlation between ECG and Cardiac Cycle

3.6K
The electrical signals recorded on an electrocardiogram (ECG) occur before the mechanical processes of contraction and relaxation during the 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...
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Tachycardia-Induced Cardiomyopathy As a Chronic Heart Failure Model in Swine
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Narrow complex tachycardia with cycle length alternans.

Swasthi S Kumar1, Sudipta Mondal1, Jyothi Vijay1

  • 1Department of Cardiology, Electrophysiology Division, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala PIN 695011, India.

Journal of Electrocardiology
|March 7, 2025
PubMed
Summary
This summary is machine-generated.

This case study discusses an elderly woman experiencing paroxysmal palpitations due to adenosine-responsive narrow complex tachycardia (NCT). The diagnosis was confirmed via electrocardiogram (ECG) findings of a regularly irregular short RP NCT.

Keywords:
AVNRTAVRTCycle length alternansLeft inferior extensionSlow pathway extensions

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Area of Science:

  • Cardiology
  • Electrophysiology
  • Internal Medicine

Background:

  • Elderly patients can present with various cardiac arrhythmias.
  • Paroxysmal palpitations are a common symptom requiring thorough investigation.
  • Narrow complex tachycardia (NCT) necessitates differential diagnosis based on electrocardiogram (ECG) characteristics.

Purpose of the Study:

  • To present a case of paroxysmal palpitations in an elderly woman.
  • To identify the underlying cause of narrow complex tachycardia (NCT).
  • To illustrate the diagnostic utility of electrocardiogram (ECG) in identifying specific tachycardia mechanisms.

Main Methods:

  • A case report of an elderly female patient presenting with palpitations.
  • Electrocardiogram (ECG) analysis during both sinus rhythm and tachycardia episodes.
  • Pharmacological stress testing with adenosine to assess tachycardia response.

Main Results:

  • The patient exhibited paroxysmal palpitations.
  • Adenosine administration revealed an adenosine-responsive narrow complex tachycardia (NCT).
  • Tachycardia ECG demonstrated a regularly irregular short RP pattern with alternating cycle lengths (320 ms and 360 ms).

Conclusions:

  • The diagnostic findings suggest a specific type of narrow complex tachycardia (NCT).
  • The short RP interval and regularly irregular pattern are key diagnostic clues.
  • This case highlights the importance of detailed ECG interpretation in diagnosing cardiac arrhythmias.