Related Experiment Video

Updated: Sep 20, 2026

Zebra II as A Novel System to Record Electrophysiological Signals in Zebrafish
06:15

Zebra II as A Novel System to Record Electrophysiological Signals in Zebrafish

Published on: August 16, 2024

Effect of amiodarone on the descending limb of the T wave

Peter Smetana1, Esther Pueyo, Katerina Hnatkova

  • 1Department of Cardiological Sciences, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, UK.

The American Journal of Cardiology
|September 16, 2003
PubMed

Insights

Amiodarone prolonged the TpTe interval in myocardial infarction patients, suggesting increased arrhythmic risk. This finding contradicts amiodarone

Area of Science:

  • Cardiology
  • Electrophysiology
  • Pharmacology

Background:

  • Myocardial infarction (MI) survivors are at risk for arrhythmias.
  • Amiodarone is an antiarrhythmic drug used post-MI.
  • TpTe interval is a marker of cardiac repolarization.

Purpose of the Study:

  • To investigate the effect of amiodarone on the TpTe interval in post-MI patients.
  • To assess the relationship between TpTe interval and arrhythmic death in patients treated with amiodarone or placebo.

Main Methods:

  • Prospective study comparing amiodarone and placebo groups post-MI.
  • Electrocardiographic measurement of TpTe interval.
  • Analysis of arrhythmic death rates.

Main Results:

  • Amiodarone significantly prolonged the rate-dependent TpTe interval.
  • Longer TpTe intervals were associated with arrhythmic death in the placebo group, but not the amiodarone group.
  • Findings suggest amiodarone may increase transmural repolarization heterogeneity and arrhythmic risk.

Conclusions:

  • Amiodarone's effect on TpTe interval contradicts previous findings of decreased repolarization heterogeneity.
  • The drug may increase arrhythmic risk despite its antiarrhythmic properties.
  • Further research is needed to clarify amiodarone's complex electrophysiological effects.

More Related Videos

A Research Method For Detecting Transient Myocardial Ischemia In Patients With Suspected Acute Coronary Syndrome Using Continuous ST-segment Analysis18:11

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

Laser-Induced Action Potential-Like Measurements of Cardiomyocytes on Microelectrode Arrays for Increased Predictivity of Safety Pharmacology10:41

Laser-Induced Action Potential-Like Measurements of Cardiomyocytes on Microelectrode Arrays for Increased Predictivity of Safety Pharmacology

Published on: September 13, 2022

Related Concept Videos

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

Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers

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 the heart's...
Antiarrhythmic Drugs: Class IV Agents as Calcium Channel Blockers01:20

Antiarrhythmic Drugs: Class IV Agents as Calcium Channel Blockers

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...
Cardiac Action Potential01:30

Cardiac Action Potential

Cardiac action potentials are essential for proper heart function, enabling the rhythmic contractions needed for adequate blood circulation. Nodal cells and Purkinje fibers, specialized for electrical conduction, generate these action potentials.
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials
Antiarrhythmic Drugs: Class I Agents as Sodium Channel Blockers01:22

Antiarrhythmic Drugs: Class I Agents as Sodium Channel Blockers

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,...
Antiarrhythmic Drugs: Class II Agents as β-Adrenergic Blockers01:24

Antiarrhythmic Drugs: Class II Agents as β-Adrenergic Blockers

Adrenergic stimulation generally impacts cardiac rate and rhythm. Specifically, stimulation of the β-adrenoceptors triggers an increase in intracellular calcium ion influx and pacemaker currents, which may cause arrhythmias. Catecholamines like adrenaline also demonstrate β2-adrenoceptor-mediated hypokalemia, impacting cardiac action potential and disrupting the normal cardiac rhythm. Class II antiarrhythmic drugs are β-adrenoceptor antagonists or β-blockers, which indirectly block calcium...
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...