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Dysrhythmia or arrhythmia are disturbances in the normal cardiac rhythm of the heart which occurs as a result of alterations within the conduction of electrical impulses. These impulses stimulate and coordinate atrial and ventricular myocardial contractions that provide cardiac output.

We are proud to present a printable cheat sheet which you can use as a guide to help you understand dysrhytmias better. There is also a download link below to be used for PDFs:

Click here: Download Dysrhythmias Cheat Sheet.docx

Dysrhtyhmia

Description

Etiology

P Wave

P-R Interval

QRS
Sinus Bradycardia Slow discharge from SA node. R<60bpm, regular rhythm, may cause decreased CO/hypertension Sleep, hypothermia hypothyroidism, vagal stimulation, suctioning, increased ICP Normal Normal Normal
Sinus Tachycardia Rapid discharges from SA node.

More than 100bpm, regular rhythm, may cause decreased CO, MI

 Hypotension, hypovolemia, fever, anemia, hypoxia, heart failure Normal Normal Normal
Premature Atrial Contraction (PAC) From an ectopic atrial foci, usually with normal conduction.

Irregular rhythm, impulse may be delayed or nonconducted, varies in rate

 May prelude supraventricular tachycardia. Stimulants, hyperthyroidism, COPD, infection and heart diseases Abnormal Variable Normal
Paroxysmal Supraventricular Tachycardia (SVT) From an ecotopic focus above the bundle of His, “re-entry” rate from 100 to 300/minute, regular rhythm. May decrease CO Exertion, Emotion, Stimulants, Rheumatic Heart Diseases Abnormal or Hidden Variable Normal
Atrial Flutter Ectopic atrial focus “re-entry” Atrial rate is 250 to 400bpm, usually with slow ventricular response CAD, Valve Problem, Hyperthyroidism Saw-tooth Shaped Variable Normal
Atrial Fibrillation Total disorganization, atrial electrical activity without effective atrial contraction.

Atrial R 300 to 600/minute.

 Usually heart diseases, also hyperthyroid, infection Chaotic Can’t be measured Normal
First Degree AV Block AB Conduction time is gradually prolonged until an atrial impulse is nonconducted and QRS is dropped then repeats CAD, drugs, RH Normal Greater than 0.20 seconds Normal
Second-Degree AV Block—Type 1 AV conduction time is gradually prolonged until an atrial impulse is nonconducted and QRS is dropped then repeats MI, drugs Normal Progressive Lengthening Normal width one not conducted
Second Degree AV Block—Type 2 Atrial impulses dropped, without antecedent lengthening P-R

Certain impulses are not conducted

 CAD, MI, digoxin Occurs in multiples Normal or Prolonged Widened preceded by two or more P waves
Third Degree—Complete AV Block No atrial impulses conducted, atrium and ventricle contract separately, result is decreased CO and heart failure Calcification of conduction system, CAD, cardiomyopathy Normal Variable Normal or Widened
Premature Ventricular Contractions (PVC) From signle or multiple ectopic focus in ventricle.

Premature and distorted QRS.

Rate is 60 to 100bpm and irregular

 Ischemia, Stimulants, hypokalemia, stress and fever None Not measurable Widened and distorted
Ventricular Tachycardia Run of three or more PVCs, ventricular focus or foci fire repeatedly.

Rate is 110 to 250bpm

 MI, CAD, Some drugs Usually none Not measurable Wide and distorted
Ventricular Fibrillation Severe derangement, firing multiple ventricular foci. No effective ventricular contraction.

Terminal if untreated.

 Ischemia, infarction, CAD, cardiomyopathy None Not measurable Wide and Distorted
Dysrhythmias Cheat Sheet Free Download

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