Arrhythmias

Cardiac Arrhythmias

rhythm – any kind of movement characterized by the regular recurrence of strong and weak elements.

“a-” without, not or opposite to

arrhythmia - An irregularity in the force or rhythm of the heartbeat.

The American Heritage® Stedman's Medical Dictionary, 2nd Edition Copyright © 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

The “irregularity” mentioned above can be in the pace or speed, the strength or weakness, or the timing of the heart beat.

Tachycardia - A rapid heart rate, especially one above 100 beats per minute in an adult.


This form is also called sinus tachycardia when the impulse is generated by the SA node. Other forms of tachycardia exist, but originate from stimuli other than the SA node and have different looking EKG readouts.

Note the fact that the heart beat shown above has a “regular” rhythm. What makes it “abnormal” is its rapid rate.

Supraventricular tachycardia – (abbr. SVT). An arrhythmia in which the impulse stimulating the heart is not generated by the sinus (SA) node, but instead comes from a collection of tissue around and involving the atrioventricular (AV) node. The electrical impulses from this abnormal site are generated at a rapid rate, which may reach 280 beats per minute.

This form is also called sinus bradycardia when the impulse is generated by the SA node. Other forms of bradycardia exist, but can be physiologic or pathologic in origin.

Pathologic – relating to or caused by disease.

Physiologic – characteristic of the normal functioning of a living organism.

Bradycardia - A slowness of the heartbeat, usually

under 60 beats per minute in adults.The American Heritage® Stedman's Medical Dictionary, 2nd Edition Copyright © 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

cardiac arrhythmia, momentarily loss of pulse, and sometimes producing accompanying palpitations (abnormal heartbeat that is often associated with a sensation of fluttering or thumping).

Premature ventricular contraction – (Abbr. PVC) An early impulse firing of the ventricles causing the ventricles to beat early, resulting in momentary

Premature atrial contraction (PAC): The atria fires an early impulse which causes the heart to beat earlier causing irregularity in the heart rhythm.

Atrial flutter – Rapid, regular atrial contractions occurring usually at rates between 250 and 400 per minute and often producing saw-tooth waves in an electrocardiogram.


Since the atrioventricular node conducts impulses slowly, it does not appear to be involved in this arrhythmia. Therefore, in this type of abnormal heart rhythm, the ventricles will appear to beat at regular (“normally” paced) intervals.

Ventricular flutter – A rare, dangerous condition that does not last long since it usually deteriorates quickly into ventricular fibrillation.

Fibrillation - Fine, rapid, uncoordinated twitching of individual muscle fibers with little or no movement of the muscle as a whole.

This condition can

occur in either the

atria or the ventricles.

Atrial fibrillation - Fibrillation in which the normal rhythmical contractions of the atria are replaced by rapid, irregular twitchings of the atrial walls as a result of many sites within the atria firing electrical impulses in an irregular fashion. This causes the ventricles to respond irregularly resulting in an irregular heart beat. Also called a-fib.

Ventricular fibrillation - An often fatal form of arrhythmia characterized by rapid, irregular, uncoordinated spasms or twitchings of the ventricles instead of normal contractions, resulting in a loss of pulse and blood pressure. Also called v-fib.

Pulse – The rhythmical dilation of arteries produced when blood is pumped outward by regular contractions of the heart, especially as palpated at the wrist or in the neck.

Which picture is a-fib and which is v-fib?

1.) ?

2.) ?v-fib

a-fib

A larger external defibrillator such as this would be used specifically to correct ventricular fibrillation in “life or death” situations usually at hospitals.

Defibrillator – An electrical device used to counteract fibrillation of the heart muscle and restore normal heartbeat by applying a brief electric shock.


An example of the inevitable use of this equipment, which often ends on a happy note.

Automated external defibrillator - (AED) is a device that can detect and correct ventricular fibrillation. V-fib is, basically, cardiac arrest. If cardiac arrest occurs, an AED, if available, should be used immediately. If the AED detects v-fib, it provides an electrical shock (defibrillation) that can restore normal heart rhythm. If a person remains in cardiac arrest after an AED is used, help should be called and CPR should be performed.

An example of an AED

An example of a defibrillator that can be implanted in a person’s chest. Often times these are coupled with an artificial pacemaker.

Health & Medicine

Arrhythmias