Presented by Moore County Hospital District

Tim DiTirro RN,BSN,CEN,NREMTP EKG Paper –

• Comes out of printer at a standard 25 mm/sec. • Made up of smaller and larger squares. • Each Small Square is 1 mm on the vertical axis and represents 0.04 sec. • Each larger square is 5 mm on the vertical axis and represents 0.20 sec. • Voltage or amplitude is measured along the vertical axis. • A one millivolt electrical signal will produce a deflection 10 mm in height

Isoelectric Line –

EKG Waveforms –

< 0.12

0.12 - 0.20 < 0.12

QT Interval < 0.38 sec EKG Waveforms –

§ P Wave; Indicates atrial Depolarization Indicates impulses originating from the SA node.

§ PR Interval; extends from the beginning of the p wave to the onset of the QRS Complex and is indicative of the delay of signal from the atria to the AV node and should not exceed 0.20 sec or five little boxes. (This important criteria for determining blocks).

EKG Waveforms – § QRS Complex – Represents the electrical depolarization of the ventricles.

§ The Q wave is the first negative or downward deflection § The R wave is the first positive or upward deflection following the p wave § The S wave is the negative wave following the R Wave. § Normal Duration of the QRS is less than 0.12 sec or 3 small boxes.

EKG Waveforms – Different Configurations of the QRS

EKG Waveforms – § ST Segment – Begins at the end of the S complex and ends at the onset of the T wave. § Represents the early part of ventricular repolarization. § Normally sits on the Isoelectric Line. § ST segment elevation or Depression of greater than 1 mm or the height of 1 small box can indicate myocardial ischemia or damage!!!!

Abnormal ST Segments –

EKG Waveforms – § T Wave – Reflects Ventricular repolarization § Begins at the end of the ST segment § Ends when the wave returns to the isoelectric line.

Rate Measurement – § The Six Second Method Can be used with either regular or irregular rhythms provides an estimated heart rate. Count the number of R waves in a 6 second strip and multiply by 10, note the 3 second marks at the bottom of the strip. Count 8 R waves in 6 sec below for a HR of 80

6 step method for Rhythm Interpretation – 1. Calculate Heart Rate 2. Determine regularity of R waves. 3. Is there 1 P wave before each QRS 4. Measure P-R interval is it = to or less than 0.20 sec 5. Duration of QRS complex, is it 0.10 to 0.12 sec. 6. Interpretation of Rhythm.

Step 1 Rate – Normal Findings Abnormal Findings § Heart rate should be § Heart rates less than 60 between 60-100 BPM BPM is Bradycardia. § Atrial Rate should the § Heart rates greater than same as the ventricular 100 BPM is Tachycardia Rate § A heart rate greater than 150 is considered SVT (supra ventricular tachycardia) Step 2 Regularity – Normal Findings Abnormal Findings § R-R intervals are regular § R-R intervals are irregular. § P-P intervals are regular § P-P intervals are irregular § There is one P for every § There is more than one P QRS. or no P for each QRS.

Sinus Rhythm Atrial Fibrillation P Wave Assessment – Normal Findings Abnormal Findings § Should be regular § P wave is not followed by § Should be upright and a QRS Complex. rounded. § There are more P waves than § Should look alike QRS Complexes. § Should be one P for

every QRS

PR Interval – Normal Findings Abnormal Findings § The PR interval is between § The PR interval is > 0.20 sec 0.12 – 0.20 seconds. ( 1st degree AV Block) § The PR intervals are § The PR interval is irregular constant throughout in measurement. the rhythm ( 2nd degree type 1 or 2 and 3rd degree complete heart block)

QRS Complex – Normal Findings Abnormal Findings § All QRS Complexes are the § Vary in shape width and same size, shape, and direction. direction. § Complex is > 0.12 sec § All QRS Complexes are of § R-R interval is irregular. equal duration and width. § R-R intervals are regular

§ ST Segment – Normal findings Abnormal findings § ST Segment should be § There is over a 1 mm sitting on the isoelectric ST segment elevation or base line or no more than depression from the 1 mm above or below the isoelectric line. ( indicative isoelectric line. of Stemi !!!! Or heart muscle Damage)

ST Segment – § ST Elevation could mean a stemi in progress § St Depression could indicate heart muscle Damage.

STEMI Sinus Rhythm –

Heart Rate 60-100 Rhythm Regular One P wave precedes every QRS PR interval 0.12 – 0.20 sec (Less than one big box) QRS width < 0.12 sec Sinus Bradycardia –

Normal Ps and QRS’s Heart Rate Less than 60 beats per minute. Sinus Tachycardia –

Normal Ps and QRS Heart Rate > 100 bpm Atrial Flutter –

Flutter Waves Atrial rate can reach 250 to 350 bpm This strip 4 to 1 conduction

Atrial Fibrillation –

No P waves. Rhythm, Regularly Irregular QRS Junctional Escape Rhythm –

Heart Rate 40 to 60 per minute impulses originate in AV Junction P waves are nonexistent or inverted 1st degree AV Block –

§ A delay in passage of the impulse from the atria to the ventricles. § Indicated by a PR interval of greater than 0.20 sec.

2nd Degree AV Block Type 1 –

§ Also Known as Wenckebach § PR interval continues to increase until a QRS is Dropped

2nd Degree AV Block Type 2 –

§ Indicated by a p wave for every QRS with a normal PR interval but has an extra un conducted P Wave. 3rd degree or complete Block –

§ No conduction between the Atria and ventricles § Atria and Ventricles beat independently § Atrial rate the same or a little faster than the ventricular rate. § Regular R-R intervals AV Block Review – § 1st Degree Block - Has P for every QRS but PR interval greater than 0.20 sec. § 2nd degree Block Type 1 – PR interval gradually increases until a QRS is Dropped. § 2nd degree Block Type 2 – The only block that has normal p wave for every QRS just has more P waves than Q waves. § 3rd degree block - No correlation between P waves and QRS Complexes, Atrium and ventricles beat independently R-R intervals are regular premature Ventricular Contractions –

§ A depolarization that occurs in the ventricles before the next expected beat. § Unifocal if all PVC’s Look The Same. § Multifocal focal if PVC’s are different directions. Ventricular Tachycardia –

§ 3 or more consecutive PVC’s in a row at a rate greater than 100. § Life Threatening. § If no pulse, Patient is in cardiac arrest Ventricular Fibrillation –

Chaotic electrical Stimuli Cardiac Arrest!!!!!!!! Needs Defibrillation.

Asystole –

§ Absence of electrical activity § Assess the patient § Check the leads § CPR and Epi, § Not a Shockable Rhythm 60 Cycle Interference –

§ Caused by the influence of other electronic equipment in the room. § Can be caused by Cell Phones ! Conclusion –

Thank You And Happy Interpretation