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Related Concept Videos

Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers01:12

Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers

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Class III antiarrhythmic drugs are a group of medications that can prolong action potentials in the heart. They achieve this by blocking potassium channels or enhancing inward currents from sodium channels. However, these drugs have a unique property of "reverse use-dependence," which is most pronounced at slower heart rates and can lead to torsades de pointes—a specific type of arrhythmia. However, it is essential to note that excessive QT interval prolongation—a measure of...
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ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias01:25

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

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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...
151
Antiarrhythmic Drugs: Class I Agents as Sodium Channel Blockers01:22

Antiarrhythmic Drugs: Class I Agents as Sodium Channel Blockers

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Class I antiarrhythmic drugs are used to treat various types of arrhythmias or irregular heart rhythms. These drugs block the sodium (Na+) channels in the cardiac cells, thereby affecting the movement of electrical impulses across the heart. Class I antiarrhythmic drugs are divided into three subgroups: Class IA, Class IB, and Class IC, each with distinct mechanisms of action and effects on the heart.
Class 1A Antiarrhythmic Drugs: These drugs work by moderately blocking sodium channels,...
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Antiarrhythmic Drugs: Class IV Agents as Calcium Channel Blockers01:20

Antiarrhythmic Drugs: Class IV Agents as Calcium Channel Blockers

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Class IV antiarrhythmic drugs, such as verapamil and diltiazem, block calcium channels. They primarily affect the heart, slowing the conduction in calcium-dependent tissues like the SA and AV nodes. These drugs manage reentrant supraventricular tachycardia (SVT) and reduce ventricular rate in atrial flutter/fibrillation.
Verapamil, a calcium channel blocker, inhibits calcium movement across myocardial cell membranes and vascular smooth muscle. This results in the dilation of coronary and...
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Disturbances in Heart Rhythm01:29

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

Dysrhythmias III: Characteristics of Dysrhythmias

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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...
107

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Prolonged QT Interval in Cirrhosis: Twisting Time?

William Lee1,2, Bert Vandenberk1,3, Satish R Raj1,4

  • 1Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.

Gut and Liver
|July 22, 2022
PubMed
Summary

Cirrhosis patients often have prolonged QT intervals, increasing arrhythmia risk. Managing this involves monitoring ECGs and avoiding drug interactions and electrolyte imbalances to improve outcomes.

Keywords:
Acquired long QT syndromeCirrhosisDrug interactionTorsade de pointesVentricular repolarization

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Area of Science:

  • Cardiology
  • Hepatology
  • Clinical Pharmacology

Background:

  • QT interval prolongation affects 30-70% of cirrhosis patients.
  • Prolonged QT is linked to ventricular arrhythmias and mortality in cirrhosis.
  • Understanding the pathophysiology and management of long QT syndrome in cirrhosis is crucial.

Purpose of the Study:

  • To provide an overview of the pathophysiology of acquired long QT syndrome in cirrhosis.
  • To outline management strategies for long QT syndrome in cirrhotic patients.
  • To highlight the association between QTc interval, liver disease severity, and mortality.

Main Methods:

  • The QT interval is corrected for heart rate (QTc) using the Fridericia method.
  • QTc prolongation is defined as >450 ms in males and >470 ms in females.
  • Pathophysiological mechanisms and risk factors were reviewed.

Main Results:

  • Potential mechanisms include metabolic, autonomic, and hormonal imbalances, cirrhotic heart failure, and genetic factors.
  • External risk factors include medications, bradycardia, electrolyte abnormalities, and cardiomyopathy.
  • Multiple factors contribute to repolarization reserve erosion in cirrhosis.

Conclusions:

  • Risk mitigation involves ECG monitoring and avoiding drug interactions and electrolyte disturbances.
  • Collaborative efforts between cardiologists and hepatologists can improve clinical outcomes.
  • Acquired long QT syndrome in cirrhosis requires a multifaceted management approach.