Cardiac Conduction System

The myocardium of the heart can generate its own electrical impulse, an ability called automaticity. The Sinoatrial node (SA node) in the right atrium works like an internal pacemaker. This node generates electrical impulses at a rate of 60-100 times per minute. Each impulse travels through internodal pathways in the right and left atria and […]

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Ventricular Fibrillation

Ventricular fibrillation, known commonly as v-fib, is caused by multiple ectopic electrical impulses that depolarize the myocardium in a chaotic fashion. This results in a quivering or fibrillating heart that does not produce a pulse or adequate cardiac output. ECG Interpretation: Rhythm Is the rhythm regular or irregular? It is irregular Rate What is the […]

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Wide Complex Ventricular Tachycardia

Wide Complex Monomorphic Ventricular Tachycardia Many wide complex tachycardias originate in the ventricles, but some do not. The ones that do not may include: Aberrant SVT, like a bundle branch block Ventricular reentry problem where the ventricles contract too early after partial repolarization (like a pre-excited tachycardia or Wolff-Parkinson White syndrome) A very common ventricular […]

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Pulseless Electrical Activity

Pulseless electrical activity, known commonly as PEA, is a condition where the electrical activity of the heart may appear normal but it is not accompanied by the mechanical function of the heart, and no pulse is present Treatable causes include: Pulmonary thrombosis Coronary thrombosis Tension pneumothorax Cardiac tamponade Hypovolemia Hyperkalemia Hypoxia Acidosis Medical professionals should […]

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Asystole

Asystole means there is no ventricular activity.  In most cases, this is a lethal arrhythmia with no electrical or mechanical activity. ECG Interpretation: Rhythm Is the rhythm regular or irregular? No rhythm Rate What is the rate? There is no rate, so no other rate findings apply P Wave Are they present? In some cases, […]

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Atrioventricular Blocks

1st Degree Atrioventricular (or AV) heart blocks are usually caused by a delayed, absent, or inconsistent electrical conduction pathway through the AV node.  These AV blocks are described as a first degree, having a prolonged PR interval beyond .20 seconds. An ECG will show the following: Rhythm is regular with a normal or slow rate […]

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Tachycardia

Tachycardia is an abnormally fast heart rate. There are a couple different definitions of tachycardia: Narrow complex Less than .12 seconds in length Wide complex. Greater than .12 seconds in length These differentiations are significant, because they’re measurable and can tell us if the cause of the arrhythmia is atrial based or ventricular based. Tachycardia […]

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Bradycardia

Bradycardia is a slow rhythm usually found to be under 60 bpm. There can be many forms of bradycardia. Regardless of the underlying reason, if bradycardia is causing the patient to display  bradycardia-related symptoms, it should be treated. An example of a bradycardia patient’s ECG might show the following: Rhythm is regular Rate is slow […]

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Atrial Flutter

On an ECG, atrial flutter resembles F waves with a sawtooth pattern.  This is the result of an ectopic atrial pacemaker or because of a rapid reentry pathway somewhere within the atria but outside of the SA node area. This ectopic pacemaker usually originates somewhere in the lower atrium and closer to the AV node, […]

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Atrial Fibrillation

There are three primary types of atrial fibrillation: Paroxysmal Atrial Fibrillation Transient episodes that stop on their own May last anywhere from seconds or minutes, to hours or up to a week Persistent Atrial Fibrillation Episodes last more than a week Episodes that last less than a week but are only stopped by either pharmacological […]

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