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Related Concept Videos

ECG Interpretation of Arrhythmias I: Sinus Arrhythmias01:16

ECG 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...
Dysrhythmias III: Characteristics of Dysrhythmias01:29

Dysrhythmias 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.
Electrophysiology of Normal Cardiac Rhythm01:19

Electrophysiology 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...
Dysrhythmias IV: Characteristics of Bradyarrhythmias01:18

Dysrhythmias 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...
Dysrhythmias II: Classification of Tachyarrhythmias01:28

Dysrhythmias II: Classification of Tachyarrhythmias

Tachyarrhythmias are a type of dysrhythmia where the heart rate exceeds 100 beats per minute. Here are some common types of tachyarrhythmias:Sinus TachycardiaSinus tachycardia originates from increased impulses from the sinus node, leading to an elevated heart rate. It is often triggered by stress, fever, or exercise.Patients may experience palpitations, a sensation of a racing heart, dizziness, and chest discomfort.Causes and Risk Factors: Common causes include physical exertion, emotional...
Dysrhythmias I: Introduction01:15

Dysrhythmias I: Introduction

Dysrhythmias refers to abnormalities in the heart's rhythm. They result from disruptions in the heart's electrical conduction system, which includes the sinoatrial(SA)node, atrioventricular(AV) node, the bundle of His, bundle branches, and Purkinje fibers.Definition and PathophysiologyDysrhythmias result from disorders of impulse formation, impulse conduction, or both. The heart contains specialized cells in the sinoatrial node, atrioventricular node, and the bundle of His and Purkinje fibers...

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Electrophysiological features in patients with sinus node dysfunction and vasovagal syncope.

Beata Graff1, Grzegorz Graff, Edward Koźluk

  • 1Hypertension Unit, Department of Hypertension and Diabetology, Medical University of Gdansk, Poland.

Archives of Medical Science : AMS
|February 14, 2012
PubMed
Summary

Patients with sinus node dysfunction and vasovagal syncope show greater sinoatrial conduction time variability. Autonomic blockade reduces variability in sinus node recovery time and pauses, aiding diagnosis.

Keywords:
sinoatrial conduction time variabilitysinus node dysfunctionsyncopetransoesophageal atrial pacingvasovagal syncope

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Area of Science:

  • Cardiology
  • Electrophysiology
  • Autonomic Nervous System

Background:

  • Syncope is a common symptom, often linked to sinus node dysfunction (SND).
  • Some patients with pacemakers for SND do not improve and are later diagnosed with vasovagal syncope (VVS).
  • Distinguishing between SND and VVS is crucial for effective treatment.

Purpose of the Study:

  • To identify electrophysiological criteria for diagnosing concurrent sinus node dysfunction and vasovagal syncope.
  • To differentiate patients with SND and VVS from those with SND alone.

Main Methods:

  • Transoesophageal atrial pacing (TAP) was conducted in 100 patients.
  • Electrophysiological parameters of sinus node function and variability were measured.
  • Measurements were taken in basal state and after autonomic blockade (AB).

Main Results:

  • Patients with concurrent SND and VVS exhibited greater sinoatrial conduction time (SACT) variability.
  • Abnormal sinus node recovery time (SNRT) and second pause (IIP) were noted in SND patients.
  • In SND and VVS patients, the variability of SNRT, corrected SNRT (cSNRT), and IIP decreased post-autonomic blockade.

Conclusions:

  • Concurrent SND and VVS patients display distinct electrophysiological features: higher SACT variability and reduced SNRT, cSNRT, and IIP variability after AB.
  • Transoesophageal atrial pacing is valuable for syncope evaluation, particularly when multiple cardiac causes are suspected.
  • Larger studies are needed to validate these electrophysiological findings.