Related Experiment Video

Updated: Jun 29, 2026

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

QT interval prolongation and arrhythmia: an unbreakable connection?

M E Anderson1

  • 1Department of Cardiovascular Medicine, Vanderbilt University Medical School, Nashville, TN, USA. mark.anderson@vanderbilt.edu

Journal of Internal Medicine
|December 13, 2005
PubMed

Insights

QT interval prolongation can increase arrhythmia risk, yet also serve as an antiarrhythmic strategy. Calmodulin kinase II (CaMKII) activation downstream of QT prolongation contributes to proarrhythmia, suggesting CaMKII inhibition as a therapeutic target.

Area of Science:

  • Cardiology
  • Molecular Biology
  • Pharmacology

Background:

  • QT interval prolongation is linked to arrhythmia risk but also used therapeutically.
  • The precise cellular mechanisms underlying QT prolongation's proarrhythmic effects remain incompletely understood.

Purpose of the Study:

  • To investigate the role of calmodulin kinase II (CaMKII) in the proarrhythmic consequences of QT interval prolongation.
  • To explore CaMKII as a potential therapeutic target for managing arrhythmias associated with QT prolongation.

Main Methods:

  • Cellular electrophysiology studies examining action potential duration and Ca2+ signaling.
  • In vivo arrhythmia models to assess the impact of CaMKII inhibition.

Main Results:

  • QT interval prolongation activates CaMKII, a specific cellular proarrhythmic signal.
  • Inhibition of CaMKII prevents arrhythmia surrogates and in vivo arrhythmias linked to excessive action potential prolongation.

Conclusions:

  • QT interval prolongation alone does not fully explain proarrhythmia; CaMKII activation is a key downstream mediator.
  • CaMKII plays a significant role in the proarrhythmic effects of excessive QT prolongation, indicating its potential as a therapeutic target.

More Related Videos

Electrocardiogram Recordings in Anesthetized Mice using Lead II04:16

Electrocardiogram Recordings in Anesthetized Mice using Lead II

Published on: June 20, 2020

Analyzing Long-Term Electrocardiography Recordings to Detect Arrhythmias in Mice06:07

Analyzing Long-Term Electrocardiography Recordings to Detect Arrhythmias in Mice

Published on: May 23, 2021

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.
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...
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 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...
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...