Basic Dysrhythmias Sinus Arrhythmias Basic Rhythm Strip Interpretation

Basic Dysrhythmias Sinus Arrhythmias

Basic Rhythm Strip Interpretation n Use a systematic approach each and every time a strip is analyzed 2

Basic Rhythm Strip Interpretation n n First, and most important, look at your patient! Read every strip from left to right. Apply the five step systematic approach. Avoid shortcuts. Be consistent 3

Basic Rhythm Strip Interpretation n n Step 1: Heart rate & Rhythm Step 2: P wave rate & Rhythm Step 3: PR Interval Step 4: QRS complex Step 5: Interpretation 4

Step 1: Heart Rate n n Six second method: count the number of QRS complexes in a six second interval on the EKG strip. Large box method: count the number of large boxes between 2 consecutive R waves (R-R Interval) and divide into 300. Small box method: count the number of small boxes between two consecutive R waves and divide into 1500. Sequence method: select an R wave that falls on a dark vertical line, number the dark vertical lines following this as 300 -150 -100 -75 -60 -50 -43 -38 -33 -30. Note where the next R wave falls. 5

Step 1: Heart Rhythm n n Is the rhythm regular or irregular? Measure the intervals between R waves to determine ventricular regularity. Measure the intervals between P waves to determine atrial regularity. If irregular, is it 1. Regularly irregular 2. Irregularly irregular 6

Step 2: the P wave n n n Are P waves present? Are the P waves occurring regularly? Is there one P wave present for each QRS complex present? What is the P-P rate? Are the P waves smooth, rounded, and upright in appearance or are they inverted? Do all the P waves look similar? 7

Step 3: The PR Interval n n n Are the PR Intervals greater than 0. 20 second? Are the PR Intervals less than 0. 12 second? Are the PR Intervals constant across the EKG strip? 8

Step 4: the QRS Complex n n n Are the QRS intervals greater than 0. 12 second? Are the QRS intervals less than 0. 12 second? Are the QRS complexes similar in appearance across the EKG strip? 9

Step 5: Interpretation n Now you are ready to interpret the rhythm. 10

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Sinus Rhythms n n n Normal Sinus Rhythm Sinus Bradycardia Sinus Tachycardia Sinus Arrhythmia Sinus Arrest 12

Sinus Rhythm n n Is it Sinus Rhythm? To ascertain whether a rhythm is sinus or not you need to be able to identify key features: ¡ ¡ ¡ There must always be a P wave. The P wave should be a rounded shape Each P wave should be the same shape Each P wave should be followed by a QRS The P-R interval should be 0. 12 to 0. 20 seconds (3 -5 small squares) and constant The rhythm should be regular. 13

Normal Sinus Rhythm 14

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Sinus Bradycardia n n n R-R intervals constant and regular All waveforms are present, and there is 1 Pwave to each QRS complex The rate is <60 bpm but not usually <40 bpm Patients usually asymptomatic and no treatment is required Often caused by beta-blockers / calcium channel blockers May also be seen in athletes and occur during sleep. 18

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Sinus Tachycardia n n n R-R intervals constant and regular One P-wave per QRS complex All waveforms present Rate is > 100 bpm, but not usually > 130 bpm at rest Occurs normally in exercise / stress. Patient is usually asymptomatic. Other causes may be hypovolemia / underlying medical problems 20

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Sinus Arrhythmia n n n n Sinus arrhythmia is not commonly seen but the same evaluation procedure is used: Is there a P wave? Is each P wave the same shape? Is each P wave followed by a QRS complex? Is the P-R interval between 3 -5 small squares? Is the rhythm regular? If the answer to the first four questions is "yes", but the answer to the last is "no" then you have sinus arrhythmia. 22

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Sinus Arrest n In disease (e. g. sick sinus syndrome) the SA node can fail in its pacing function. If failure is brief and recovery is prompt, the result is only a missed beat (sinus pause). If recovery is delayed and no other focus assumes pacing function, cardiac arrest follows. 24

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