Heart Rhythm Disorders and Arrhythmias

Flashcards reviewing heart rhythm disorders, resting heart rate abnormalities, and electrical conduction conditions based on lecture notes.

What is arrhythmia, and what is its primary cause?

Arrhythmia is the loss of the normal rhythm of the heartbeat, usually caused by an abnormality in the electrical conduction system of the heart.

What is bradycardia, and what resting heart rate defines it?

Bradycardia is an abnormally slow resting heart rate, usually applied to a heartbeat rate of less than $60\text{ beats per minute}$ or BPM.

What mechanism can cause bradycardia?

Bradycardia can occur when the passage of electricity from the top to the bottom of the heart is partially or totally blocked.

What is tachycardia, and what resting heart rate defines it?

Tachycardia is an abnormally rapid resting heart rate, usually applied to a heartbeat rate of greater than $100\text{ bpm}$.

What is paroxysmal supraventricular tachycardia?

Paroxysmal supraventricular tachycardia is an episode that begins and ends abruptly during which there are very rapid and irregular heartbeats originating at or above the atrioventricular node.

What is ventricular tachycardia (V tach), and why is it dangerous?

Ventricular tachycardia is a very rapid heartbeat that begins within the ventricles. It is potentially fatal because the heart beats so rapidly that it cannot adequately pump blood through the body.

Which device can control ventricular tachycardia for some patients?

An implantable cardioverter defibrillator.

What is asystole, and what is its medical significance?

Asystole, also known as a flat line, is the complete lack of electrical activity in the heart. The resulting lack of heart contractions and blood flow is one of the conditions required to certify death.

What is cardiac arrest?

Cardiac arrest is an event in which the heart abruptly stops beating or develops an arrhythmia that prevents it from pumping blood effectively.

How does sudden cardiac death occur relative to cardiac arrest?

Sudden cardiac death results when treatment of cardiac arrest is not provided within a few minutes.

What is heart block?

Heart block is a congenital or acquired arrhythmia caused by the electrical signal moving through the heart being partially or completely blocked from reaching the ventricles.

What is Long QT syndrome (LQTS)?

Long QT syndrome (LQTS) is an inherited or medically acquired heart rhythm disorder named for an unusual electrocardiogram pattern that can cause fast, chaotic, and potentially dangerous arrhythmias.