ECG TRAINING MODULE 4 BY BRAD CHAPMAN RCT

OBJECTIVES Arrhythmia recognition Sinus Atrial Blocks Ventricular

ARRHYTHMIA RECOGNITION Rhythms coming from the SA node:   Normal Sinus Rhythm: This rhythm originates from the SA node. This specialized piece of tissue generates its own impulse at a rate of 60 – 100 bpm. Sympathetic stimulation can accelerate the SA node up to a rate of 150 bpm. (Woods, 2000). P waves and QRS are usually normal and have a 1:1 ratio. Rate: 60 – 100 bpm (beats per minute), Regular

ARRHYTHMIA RECOGNITION Sinus Bradycardia: Rhythm - Regular Rate - less than 60 beats per minute QRS Duration - Normal P Wave - Visible before each QRS complex P-R Interval - Normal Usually benign and often caused by patients on beta blockers

ARRHYTHMIA RECOGNITION Sinus Tachycardia: Rhythm - Regular Rate - More than 100 beats per minute QRS Duration - Normal P Wave - Visible before each QRS complex P-R Interval - Normal The impulse generating the heart beats are normal, but they are occurring at a faster pace than normal. Seen during exercise

ARRHYTHMIA RECOGNITION Sinus arrhythmia: The EKG is of normal pattern but the rhythm varies corresponding to respiratory cycle. This is commonly found in young people. P waves and QRS are usually normal and have a 1:1 ratio.

ARRHYTHMIA RECOGNITION Sinus Arrest: The S.A. node fails to initiate impulses. No P waves, No QRS

ARRHYTHMIA RECOGNITION Atrial Rhythms   These rhythms come from a different focus or site than the S.A. node (normal pacemaker of the heart). Usually somewhere within the wall of one of the atria. The P wave is often of different shape. The QRS is usually initiated in a normal manner.

ARRHYTHMIA RECOGNITION Atrial Flutter: The waves are very rapid (300 bpm) – usually saw tooth in pattern. The A-V node cannot transmit every impulse to the ventricle. The ventricle will respond to every second, third, fourth etc. flutter wave. Rhythm - Regular Rate - Around 110 beats per minute QRS Duration - Usually normal P Wave - Replaced with multiple F (flutter) waves, usually at a ratio of 2:1 (2F - 1QRS) but sometimes 3:1 P Wave rate - 300 beats per minute P-R Interval - Not measurable As with SVT the abnormal tissue generating the rapid heart rate is also in the atria, however, the atrioventricular node is not involved in this case

ARRHYTHMIA RECOGNITION Atrial fibrillation: There are no consistent P waves. Because the irritable focus is so rapid (more than 350 bpm) You see wavy series of fib waves. The ventricular response is totally irregular. Rhythm - Irregularly irregular Rate - usually 100-160 beats per minute but slower if on medication QRS Duration - Usually normal P Wave - Not distinguishable as the atria are firing off all over P-R Interval - Not measurable The atria fire electrical impulses in an irregular fashion causing irregular heart rhythm

ARRHYTHMIA RECOGNITION AV NODE RHYTHMS   When the pacemaker of the heart shifts down to the A.-V. node, the P waves are altered. This causes the P waves to be inverted. Because the focus is so close to the ventricle, the atria and ventricle contract at about the same time. The P wave occurs just before, after or buried in the QRS complex. Nodal rhythm: The rhythm is regular but the P wave occurs just before the QRS, after or is buried in the QRS. Your P wave can also be inverted. Nodal Tachycardia: The rate is usually between 100 and 150 bpm. Since conduction beyond the A-V node is normal, we usually get a QRS complex which is normal. Inverted P waves are seen.

ARRHYTHMIA RECOGNITION 1st Degree AV Block: Prolonged AV conduction time. If the pacemaker is normal and in the S.A. node the P wave will be normal in shape. But because of defective (slow) conduction in the A.V. node, the PR interval exceeds the upper limit or normal. The heart rate and rhythm are unaffected. Your PR interval is greater than .20 sec. (200) Rhythm - Regular Rate - Normal QRS Duration - Normal P Wave - Ratio 1:1 P Wave rate - Normal P-R Interval - Prolonged (>5 small squares) 

ARRHYTHMIA RECOGNITION 2nd Degree Block Type 1 (Wenckebach) Here, there is a progressive lengthening of the PR interval to the point where an impulse does not reach the ventricle and a beat is dropped. Rhythm - Regularly irregular Rate - Normal or Slow QRS Duration - Normal P Wave - Ratio 1:1 for 2,3 or 4 cycles then 1:0. P Wave rate - Normal but faster than QRS rate P-R Interval - Progressive lengthening of P-R interval until a QRS complex is dropped  

ARRHYTHMIA RECOGNITION 2nd Degree Block (Mobitz Type II) This is characterized by an occasional or cyclic block of conduction of an impulse without previous lengthening of conduction time. Rhythm - Regular Rate - Normal or Slow QRS Duration - Prolonged P Wave - Ratio 2:1, 3:1 P Wave rate - Normal but faster than QRS rate P-R Interval - Normal or prolonged but constant

ARRHYTHMIA RECOGNITION 3rd Degree AV Block: Usually called a complete heart block. There is a delay before the idioventricular pacemaker goes in action. During this time there is no ventricular contraction (no QRS) and often times the patient may faint. There is no impulse from the atria that is reaching the ventricle. Rhythm - Regular Rate - Slow (Ventricular rate 20 – 40 bpm) QRS Duration - Prolonged P Wave - Unrelated P Wave rate - Normal but faster than QRS rate P-R Interval - Variation Complete AV block. No atrial impulses pass through the atrioventricular node and the ventricles generate their own rhythm

ARRHYTHMIA RECOGNITION Right and Left Bundle Branch Blocks: When the conduction through the right and left bundles are impaired, the impulse must travel through non specialized tissue. This prolongs depolarization producing a longer QRS complex.

ARRHYTHMIA RECOGNITION The Criteria for a LBBB: -Wide QRS complex greater than .12 seconds -Upright, possibly notched QRS complex (RSR’) in lead I, V5 and V6. -Predominantly negative QRS in V1. Rhythm - Regular Rate - Normal QRS Duration - Prolonged P Wave - Ratio 1:1 P Wave rate - Normal and same as QRS rate P-R Interval - Normal

ARRHYTHMIA RECOGNITION The Criteria for a RBBB: -Wide QRS of at least .11 seconds -An RSR’ in V1 and V2 -Wide S wave in leads I and V6.  

ARRHYTHMIA RECOGNITION Ventricular rhythms:   These impulses are coming from the wall of the ventricles. Ventricular tachycardia: This is a dangerous rhythm which requires immediate attention and prompt correction. Rhythm - Regular Rate - 180-190 Beats per minute QRS Duration - Prolonged P Wave - Not seen Results from abnormal tissues in the ventricles generating a rapid and irregular heart rhythm. Poor cardiac output is usually associated with this rhythm thus causing the pt to go into cardiac arrest. Shock this rhythm if the patient is unconscious and without a pulse  

ARRHYTHMIA RECOGNITION Ventricular fibrillation: The pattern is bizarre with no rhythm of any sort. You usually have no palpable or audible pulse. Rhythm - Irregular Rate - 300+, disorganised QRS Duration - Not recognisable P Wave - Not seen This patient needs to be defibrillated!! QUICKLY

REVIEW No questions will be asked for this module as it is for information only and you will not be expected to know these blocks.