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Related Concept Videos

Mechanism of Cardiac Arrhythmias01:28

Mechanism of Cardiac Arrhythmias

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.
Disturbances in Heart Rhythm01:29

Disturbances in Heart Rhythm

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 heart...
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 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.
Dysrhythmias V: Evaluating Dysrhythmias01:30

Dysrhythmias V: Evaluating Dysrhythmias

Dysrhythmias, also known as arrhythmias, are disturbances in the heart's rhythm that range from benign to life-threatening. A thorough evaluation is crucial for appropriate management and involves a comprehensive medical history, physical examination, and various diagnostic tests.Medical HistorySymptoms: Collect detailed information on palpitations, dizziness, syncope, chest pain, and fatigue. Note their onset, frequency, and triggers.Previous Cardiac Issues: Document any history of heart...
ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias01:25

ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias

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...

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Related Experiment Video

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A Research Method For Detecting Transient Myocardial Ischemia In Patients With Suspected Acute Coronary Syndrome Using Continuous ST-segment Analysis
18:11

A Research Method For Detecting Transient Myocardial Ischemia In Patients With Suspected Acute Coronary Syndrome Using Continuous ST-segment Analysis

Published on: December 28, 2012

T wave alternans for ventricular arrhythmia risk stratification.

J L Sturdivant1, M R Gold

  • 1Division of Cardiology, Medical University of South Carolina, Charleston, SC 29410, USA.

Minerva Cardioangiologica
|March 26, 2003
PubMed
Summary

T wave alternans (TWA) is a promising tool for identifying patients at risk of sudden cardiac death. This heart rate-dependent measure predicts arrhythmias and aids in risk stratification across various cardiac conditions.

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Area of Science:

  • Cardiology
  • Electrophysiology
  • Medical Diagnostics

Background:

  • Sudden cardiac death (SCD) is a major cause of mortality in Europe and the US.
  • Identifying high-risk individuals is crucial for timely and effective intervention.
  • Current risk stratification methods require enhancement for improved patient outcomes.

Purpose of the Study:

  • To evaluate T wave alternans (TWA) as a novel risk stratification tool for sudden cardiac death.
  • To assess the predictive accuracy of TWA for arrhythmic events and inducibility of ventricular tachycardia.
  • To explore the application of TWA in diverse patient populations with cardiovascular diseases.

Main Methods:

  • T wave alternans (TWA) measurement at heart rates of 100-120 bpm, achieved via exercise or atrial pacing.
  • Correlation of TWA results with programmed stimulation testing for ventricular tachycardia inducibility.
  • Application of TWA testing in patient cohorts including coronary artery disease, nonischemic cardiomyopathy, congestive heart failure, and those with implantable defibrillators.

Main Results:

  • T wave alternans (TWA) demonstrated significant predictive value for ventricular tachycardia inducibility.
  • TWA successfully predicted spontaneous arrhythmic events in various patient groups.
  • The test showed applicability and promise in diverse cardiovascular disease populations.

Conclusions:

  • T wave alternans (TWA) is a valuable non-invasive test for assessing arrhythmia vulnerability and stratifying sudden cardiac death risk.
  • TWA shows potential for guiding clinical therapy, although further research is needed to fully elucidate its role.
  • The findings support TWA as a promising diagnostic tool in cardiology practice.