A Case of LBBB-Dependent AVRT Via a Decrementally Conducting Kent Bundle

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...

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...

The cardiac conduction system produces and transmits electrical impulses that prompt myocardial contraction, ensuring efficient heart function. This intricate system ensures that the heart beats in a coordinated and efficient manner, beginning with the atria and then the ventricles. The conduction system optimizes cardiac output by maintaining this precise sequence, which is crucial for adequate blood circulation.
This system relies on the unique properties of nodal and Purkinje cells:...

Autorhythmicity is a term that refers to the heart's inherent ability to generate electrical signals and instigate muscle contractions. This self-regulating conduction system within the heart consists of two key components: the pacemaker cells and specialized conducting cells.
The pacemaker cells are located in two primary nodes: the sinoatrial (SA) node and the atrioventricular (AV) node. The SA node pacemaker cells can autonomously depolarize, triggering an action potential that leads to the...

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...

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...