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Related Concept Videos

Disturbances in Heart Rhythm01:28

Disturbances in Heart Rhythm

930
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...
930
Mechanism of Cardiac Arrhythmias01:28

Mechanism of Cardiac Arrhythmias

909
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.
909
ECG Interpretation of Arrhythmias I: Sinus Arrhythmias01:16

ECG Interpretation of Arrhythmias I: Sinus Arrhythmias

208
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,...
208
Decreased pulse rate01:14

Decreased pulse rate

536
Bradycardia is a medical condition in which the heart rate is slower than normal. It occurs when the heart's natural pacemaker, the sinus node, generates slower electrical impulses than the standard rhythm. In adults, bradycardia is diagnosed when the pulse rate falls below 60 beats per minute, indicating a deviation from the normal heart rate range.
There are specific risk factors that can elevate the likelihood of developing bradycardia. Advanced age is a significant factor, with...
536
Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers01:12

Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers

962
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...
962
Synthesis and Regulation of Thyroid Hormones01:20

Synthesis and Regulation of Thyroid Hormones

4.5K
Low blood levels of the thyroid hormones — triiodothyronine (T3) and thyroxine (T4) — signal the hypothalamus to release the thyrotropin-releasing hormone (TRH). TRH then reaches the pituitary gland and stimulates the release of thyroid-stimulating hormone(TSH) into the bloodstream.
Upon reaching the thyroid gland, TSH stimulates the follicular cells' active uptake of iodide ions from the blood. The ions diffuse to the apical surface of the cells and are oxidized to iodine. The...
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Updated: Jun 20, 2025

Author Spotlight: Integrating Ultrasound Imaging with Biochemical Markers for Thyroid Disease Diagnosis
05:41

Author Spotlight: Integrating Ultrasound Imaging with Biochemical Markers for Thyroid Disease Diagnosis

Published on: February 9, 2024

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[Arrhythmias in thyroid dysfunction].

Roman Brenner1, Stefan Bilz2, Sonia Busch3,4

  • 1Klinik für Kardiologie, Kantonsspital St. Gallen, Rorschacherstrasse 95, 9007, St. Gallen, Schweiz. roman.brenner@kssg.ch.

Herzschrittmachertherapie & Elektrophysiologie
|July 18, 2024
PubMed
Summary
This summary is machine-generated.

Thyroid dysfunction significantly impacts heart rhythm, increasing risks for atrial fibrillation and ventricular arrhythmias. Prompt treatment of thyroid imbalances and arrhythmias is crucial for managing cardiac complications.

Keywords:
Atrial fibrillation ablationHyperthyroidismHypothyroidismThyroid disorderVentricular tachycardia

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Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
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Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
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Area of Science:

  • Cardiology
  • Endocrinology
  • Molecular Biology

Background:

  • Thyroid hormones (T4) influence cardiac function through genomic and non-genomic pathways.
  • Thyroid dysfunction is linked to significant alterations in heart rate and rhythm.
  • Atrial fibrillation (AF) and ventricular arrhythmias are common complications.

Purpose of the Study:

  • To elucidate the mechanisms linking thyroid dysfunction to cardiac arrhythmias.
  • To outline therapeutic strategies for managing arrhythmias in thyroid disorders.
  • To explore the association between thyroid hormones and ventricular arrhythmias.

Main Methods:

  • Review of existing literature on thyroid hormones and cardiac electrophysiology.
  • Analysis of mechanisms underlying arrhythmia generation in hyperthyroidism.
  • Examination of epidemiological data on thyroid levels and cardiac events.

Main Results:

  • Hyperthyroidism promotes AF through increased automaticity, shortened refractory period, and slowed conduction.
  • Thyroid dysfunction necessitates rate control and anticoagulation for AF management.
  • Elevated T4 levels correlate with ventricular arrhythmias and sudden cardiac death, particularly in patients with cardiac disease.

Conclusions:

  • Thyroid dysfunction poses a significant risk for developing both atrial and ventricular arrhythmias.
  • Management requires addressing the underlying thyroid issue, controlling heart rate, and considering anticoagulation.
  • AF recurrence after ablation is more likely in hyperthyroid patients.