Cardiac Arrhythmias Jon W. Atkinson, B.S., RPSGT
Objectives AASM technical considerations AASM scoring recommendations Conduction pathway and the cardiac cycle Process for identifying arrhythmias Examples Interventions Recording and monitoring techniques
AASM technical considerations Modified lead II is recommended Additional leads may be placed if clinically indicated at the discretion of the practitioner Filters: HFF 70 Hz, LFF 0.3 Hz Digital Resolution, 12 bits Sampling rate, desirable 500 Hz, minimal 200 Hz Standard ECG electrodes are suggested rather than gold cups
AASM Scoring Recommendations Score sinus tachycardia during sleep for sustained HR > 90 BPM for adults Score bradycardia during sleep for sustained HR < 40 BPM, ages 6-adult Score asystole for cardiac pauses > 3 seconds duration, ages 6-adult Score wide complex tachycardia for a rhythm lasting a minimum of 3 consecutive beats at a rate > 100 BPM with a QRS duration > 0.12 seconds
AASM Scoring Recommendations Score narrow complex tachycardia for a rhythm lasting a minimum of 3 consecutive beats at a rate > 100 BPM with a QRS duration < 0.12 seconds Score atrial fibrillation if there is an irregularly irregular ventricular rhythm associated with the replacement of consistent P waves by rapid oscillations that vary in size, shape and timing.
AASM Scoring Recommendation Significant arrhythmias such as blocks should be reported if the quality of single lead is sufficient for accurate scoring Ectopic beats should be reported if felt to be clinically significant
Conduction Pathway and the Cardiac Cycle Ab basic understanding di of fthe normal conduction pathway of the heart and the interrelation ti of the events in the cardiac cycle must be considered before any discussion i on abnormal heart rhythms occurs
Basic Anatomy and Pathways SA node AV Node Bundle of His Left and Right Bundle Branches Purkinje System
Conducting System
ECG Waveforms
Cardiac Cycle Relationship between anatomy and cardiac cycle events P wave = atrial depolarization QRS complex = ventricular depolarization T wave = ventricular repolarization PR interval(last portion from the end of the P wave) = the pause between atrial and ventricular depolarization
Cardiac Cycle Atrial depolarization Ventricular repolarization PR interval QRS interval Ventricular depolarization and Atrial repolarization
HR = 60-100 bpm Normal PR interval = 0.12-0.20 sec QRS interval < 0.12 sec SA node discharge = 60-100/min AV node discharge = 40-60/min Ventricular tissue discharge = 20-40/min Rhythm = regular
Normal Sinus Rhythm Parameter/waveform Value/characteristic P wave Present, each appears the same QRS complex Present, each appears the same PR interval 0.12-0.20 seconds QRS interval 0.04-0.12 seconds P:QRS ratio 1:1 Rate 60-100 bpm Rhythm Regular Normal sinus rhythm, 30 second display Normal sinus rhythm, 10 second display
What is Abnormal? An arrhythmia is present if there is: Disturbance of impulse formation Disturbance of impulse conduction Both of the above occur The rate is too fast or too slow
Process for Arrhythmia Identification Tools for the systematic analysis of cardiac arrhythmias
Examine the P Wave Absent or present? Morphology the same? Examine the QRS complex Absent or present? Morphology the same?
Relationship Between P and P for every QRS QRS for every P 1:1 relationship QRS Measure the intervals Measure the PR interval Normal, too short, too long? Measure the QRS interval Normal or too long?
Regular or Irregular Rhythm Is R-R interval constant? Is P-P interval constant? Rate Times 2 method - count the number of beats in a 30 sec screen and multiply by 2 Times 4 method - count the number of beats in 15 seconds and multiply by 4 Times 6 method - count the number of beats in 10 seconds and multiply by 6 Don t rely on cardiotachometer on the study Usually derived from the pulse oximeter and can be inaccurate
Atrial Arrhythmias PAC s Sinus bradycardia Atrial tachycardias Sinus arrhythmia Sinus pauses Paroxysmal tachycardias Atrial fibrillation Atrial flutter
Premature Atrial Contractions Parameter/waveform P wave QRS complex PR interval QRS interval P:QRS ratio 1:1 Rate Rhythm (PAC s) Value/characteristic Present, appearance of the P wave of the abnormal beat is different (arises from a different location.) Present, each appears the same 0.12-0.20 seconds (may vary slightly with the abnormal beat) 0.04-0.12 seconds 60-100 bpm Irregular, P-P and R-R intervals are different Premature atrial contraction, 30 second display Premature atrial contraction, 10 second display
Sinus Bradycardia Parameter/waveform Value/characteristic P wave Present, each appears the same QRS complex Present, each appears the same PR interval 0.12-0.20 seconds QRS interval 0.04-0.12 seconds P:QRS ratio 1:1 Rate <60 bpm (<40 in sleep) Rhythm Regular Sinus bradycardia, 30 second display Sinus bradycardia, 10 second display
Atrial Tachycardias Parameter/waveform P wave QRS complex PR interval QRS interval Value/characteristic Present, each appears the same; may not be well defined in SVT Present, each appears the same 0.12-0.20 seconds 0.04-0.12 seconds P:QRS ratio 1:1 Rate Rhythm >100 bpm (> 90 bpm in sleep) Regular Atrial tachycardia, 30 second display Atrial tachycardia, 10 second display
Sinus Arrhythmia Parameter/waveform Value/characteristic P wave Present, each appears the same QRS complex Present, each appears the same PR interval 0.12-0.20 seconds QRS interval 0.04-0.12 seconds P:QRS ratio 1:1 Rate Usually 60-100 bpm Rhythm Irregular Sinus arrhythmia, 30 second display Sinus arrhythmia, 10 second display
Sinus Pauses Parameter/waveform P wave Value/characteristic Absent during pause QRS complex Absent during pause PR interval QRS interval P:QRS ratio 1:1 Rate Rhythm Absent during pause Absent during pause 60-100 bpm, but any rate is possible Irregular Sinus pause, 30 second display Sinus pause, 10 second display
Paroxysmal Tachycardias Parameter/waveform P wave Value/characteristic Present, aberrant, often hidden QRS complex Present, appearance is the same may be aberrant PR interval 0.12-0.20 seconds QRS interval 0.04-0.12 seconds P:QRS ratio 1:1 Rate 150-250 bpm Rhythm Regular during paroxysm Paroxysmal atrial tachycardia,,paroxysmal supraventricular tachycardia, 30 second display Paroxysmal atrial tachycardia, paroxysmal supraventricular tachycardia, 10 second display
Atrial Fibrillation Parameter/waveform P wave Value/characteristic None, fibrillatory wave present QRS complex Present, appearance is the same PR interval QRS interval P:QRS ratio Rate Rhythm Not measurable 0.04-0.12 seconds Not applicable Ventricular rate highly variable Irregularly irregular Atrial fibrillation, 30 second display Atrial fibrillation, 10 second display
Atrial Flutter Parameter/waveform P wave Value/characteristic None, saw tooth appearance flutter waves present QRS complex Present, appearance is the same PR interval QRS interval P:QRS ratio Rate Rhythm Not measurable 0.04-0.12 seconds Variable 2:1, 3:1, 4:1, etc Atrial 250-400, ventricular depends on degree of block Regular or irregular dependent on variability of block Atrial flutter, 30 second display Atrial flutter, 10 second display
Junctional Arrhythmias Premature junctional contraction Junctional rhythm Accelerated junctional rhythm Junctional tachycardia
Premature Junctional Contraction, PJC Parameter/waveform P wave: QRS complex: PR Interval: QRS Interval: P to QRS Ratio: Rhythm: Rate: Value/characteristic Premature and abnormal configuration, will be inverted; can be before (with shortened PR interval), after or hidden in the QRS Present, appearance is the same Shorter than normal; < 0.12 seconds 0.04-0.12 seconds?; < 1:1 if hidden; 1:1 if inverted P is seen Irregular Usually normal but can occur in sinus tachycardia or sinus bradycardia Premature junctional contraction, 30 second display Premature junctional contraction, 10 second display
Junctional (Nodal) Rhythm Parameter/waveform P wave: QRS complex: PR Interval: QRS Interval: P to QRS Ratio: Rhythm: Rate: Value/characteristic If seen, abnormal configuration, will be inverted; can be before (with shortened PR interval), after or hidden in the QRS Present, appearance is the same Shorter than normal; < 0.12 seconds 0.04-0.12 seconds?; < 1:1 if hidden; 1:1 if inverted P is seen Regular 40-60 bpm Junctional (nodal) rhythm, 30 second display Junctional (nodal) rhythm, 10 second display
Accelerated Junctional Rhythm Parameter/waveform P wave: QRS complex: PR Interval: QRS Interval: P to QRS Ratio: Rhythm: Rate: Value/characteristic If seen, abnormal configuration, will be inverted; can be before (with shortened PR interval), after or hidden in the QRS Present, appearance is the same Shorter than normal; < 0.12 seconds 0.04-0.12 seconds?; < 1:1 if hidden; 1:1 if inverted P is seen Regular 60-100 bpm Accelerated junctional (nodal) rhythm, 30 second display Accelerated junctional (nodal) rhythm, 10 second display
Junctional (Nodal) Tachycardia Parameter/waveform P wave: QRS complex: PR Interval: QRS Interval: P to QRS Ratio: Rhythm: Rate: Value/characteristic If seen, abnormal configuration, will be inverted; can be before (with shortened PR interval), after or hidden in the QRS Present, appearance is the same Shorter than normal; < 0.12 seconds 0.04-0.11 seconds?; < 1:1 if hidden; 1:1 if inverted P is seen Regular >100 bpm Junctional Tachycardia, 30 second display Junctional Tachycardia, 10 second display
AV Blocks 1 st degree AV block 2 nd degree AV block, Mobitz type I 2 nd degree AV block, Mobitz type 2 3 rd degree AV block
1 st Degree AV Block Parameter/waveform Value/characteristic P wave Present, each appears the same QRS complex Present, each appears the same PR interval >0.20 seconds QRS interval 0.04-0.12 seconds P:QRS ratio 1:1 Rate Usually normal Rhythm Regular 1 st degree AV block, 30 second display 1 st degree AV block, 10 second display
2nd Degree AV Block, Type I Parameter/waveform P wave Value/characteristic Present, normal sinus P, some not followed by QRS QRS complex Present, each appears the same PR interval QRS interval P:QRS ratio >1:1 Rate Rhythm Progressively lengthening 0.04-0.12 seconds Usually slow to normal Irregular 2nd degree AV block, type I, Wenkebach, 30 second display 2 nd degree AV block, type I, Wenkebach, 10 second display
2nd Degree AV Block, Type II Parameter/waveform Value/characteristic P wave Present, normal sinus P, some not followed by QRS complex, often >= 2 P waves before QRS complex QRS complex PR interval QRS interval P:QRS ratio >1:1 Rate Rhythm Present, each appears the same Constant PR interval before dropped QRS, may be normal or prolonged PR interval 0.04-0.12 seconds Usually slow to normal Irregular 2nd degree AV block, type II, 30 second display 2 nd degree AV block, type II, 10 second display
Parameter/waveform 3rd Degree AV Block Value/characteristic P wave Present, normal sinus P, some not followed by QRS complex, often >= 2 P waves before QRS complex QRS complex PR interval QRS interval P:QRS ratio >1:1 Rate Rhythm Present, appearance is the same Highly variable <0.12 if block is high conducting system (bundle of His) or >0.12 if lower conducting system (bundle branches) Ventricular rate 40-60 if block is high, <40 if block is lower Regular P-P and regular R-R intervals but not the same rate 3rd degree AV block, 30 second display 3 rd degree AV block, 10 second display
Ventricular Arrhythmias Premature Ventricular Contractions Unifocal PVC s Multifocal PVC s Ventricular Trigeminy Ventricular Bigeminy Ventricular couplets Idioventricular Rhythm Accelerated Ventricular Rhythm Ventricular Tachycardia Runs of ventricular tachycardia Sustained ventricular tachycardia Ventricular Fibrillation
Unifocal PVC s Parameter/waveform P wave: QRS complex: PR Interval: QRS Interval: Value/characteristic Not present with abnormal beat(s) Occurs earlier than expected and appears widened and bizarre compared to sinus originated beats None P to QRS Ratio: < 1:1 Rhythm: Rate: > 0.12 sec Irregular Usually 60-100 but can occur with faster or slower rates Unifocal PVC s, 30 second display Unifocal PVC s, 10 second display
Multifocal PVC s Parameter/waveform Value/characteristic P wave: Not present with abnormal beat(s) QRS complex: Occurs earlier than expected and appears widened d and bizarre compared to sinus originated beats. QRS complexes have different morphology PR Interval: None QRS Interval: > 0.12 sec P to QRS Ratio: < 1:1 Rhythm: Irregular Rate: Usually 60-100 but can occur with faster or slower rates Multifocal PVC s s, 30 second display Multifocal PVC s, 10 second display
Ventricular Bigeminy Parameter/waveform P wave: QRS complex: PR Interval: QRS Interval: Value/characteristic Not present with abnormal beat(s) Occurs earlier than expected and appears widened and bizarre compared to sinus originated beats. Every other beat is abnormal None P to QRS Ratio: < 1:1 Rhythm: Rate: >0.11-0.12 sec Irregular Usually 60-100 but can occur with faster or slower rates Ventricular bigeminy, 30 second display Ventricular bigeminy, 10 second display
Ventricular Trigeminy Parameter/waveform Value/characteristic P wave: Not present with abnormal beat(s) QRS complex: Occurs earlier than expected and appears widened d and bizarre compared to sinus originated beats. Every third beat is abnormal PR Interval: None QRS Interval: >0.11-0.12 sec P to QRS Ratio: < 1:1 Rhythm: Irregular Rate: Usually 60-100 but can occur with faster or slower rates Ventricular trigeminy, 30 second display Ventricular trigeminy, 10 second display
Ventricular Couplets Parameter/waveform Value/characteristic P wave: Not present with abnormal beat(s) QRS complex: Occurs earlier than expected and appears widened d and bizarre compared to sinus originated beats. Ventricular beats are paired, may be multifocal PR Interval: None QRS Interval: > 0.12 sec P to QRS Ratio: < 1:1 Rhythm: Irregular Rate: Usually 60-100 but can occur with faster or slower rates Ventricular couplets, 30 second display Ventricular couplets, 10 second display
Ventricular Rhythm Parameter/waveform Value/characteristic P wave: Not present QRS complex: Widened and bizarre PR Interval: None QRS Interval: > 0.12 sec P to QRS Ratio: < 1:1 Rhythm: Regular Rate: < 40 bpm Ventricular rhythm, 30 second display Ventricular rhythm, 10 second display
Accelerated Ventricular Rhythm Parameter/waveform Value/characteristic P wave: Not present QRS complex: l Wid Widened d and d bizarre bi PR Interval: None QRS Interval: > 0.12 sec P to QRS Ratio: < 1:1 Rhythm: Regular Rate: 40-100 bpm Accelerated ventricular rhythm, 30 second display Accelerated ventricular rhythm, 10 second display
Runs of Ventricular Tachycardia Parameter/waveform P wave: QRS complex: PR Interval: QRS Interval: Value/characteristic Not present Widened and bizarre None P to QRS Ratio: < 1:1 Rhythm: Rate: >0.11-0.12 sec Regular 100-250 bpm during the run Accelerated ventricular rhythm, 30 second display Runs of ventricular tachycardia, 30 second display Runs of ventricular tachycardia, 10 second display
Sustained Ventricular Tachycardia Parameter/waveform P wave: Value/characteristic Not present QRS complex: Widened d and bizarre PR Interval: QRS Interval: None P to QRS Ratio: < 1:1 Rhythm: Rate: > 0.12 sec Regular 100-250 bpm Sustained ventricular tachycardia, 30 second display Sustained ventricular tachycardia, 10 second display
Ventricular Fibrillation Parameter/waveform P wave: QRS complex: PR Interval: QRS Interval: P to QRS Ratio: Rhythm: Rate: Value/characteristic Not present None, wave forms are chaotic and disorganized, variable size and morphology None Not measurable None Chaotic Not measurable Ventricular fibrillation, 30 second display Ventricular fibrillation, 10 second display
Interventions Facility policy for dealing with severe arrhythmias. Sustained tachyarrhythmias (atrial or junctional tachycardias and ventricular tachycardias), atrial fibrillation ill and flutter with rapid ventricular response, and sustained ventricular arrhythmias (idioventricular or accelerated ventricular rhythm) The above require immediate patient assessment level of consciousness, dizziness or lightheadedness, presence of chest, arm or neck pain, and blood pressure. in the case of unresponsiveness, activate EMS according to protocol
Interventions Other arrhythmias runs of ventricular tachycardia, cardia asystoles, stoles second and third degree blocks previously undocumented atrial fibrillation or flutter call to the medical director, referring physician or house officer for direction, according to protocol.
Recording and Monitoring Techniques A single prescribed or mandated electrode combination may not always demonstrate a well defined P wave or a QRS complex of sufficient amplitude. The EKG quality should be observed before or during the physiologic calibration procedure. If the AASM recommended Modified Lead II derivation does not provide an adequate P wave or QRS complex, change it Different lead combinations should be sampled to provide the most adequate sample of the EKG prior to lights out.
Recording and Monitoring Techniques Better tactic - routinely monitor two separate EKG leads, e.g. a Lead I and a Lead II, or a Lead I and a Lead III simultaneously. There are recording systems that have the capability of displaying avr, avl, and avf), the augmented limb leads. Viewing of the EKG and arrhythmia recognition is facilitated by spreading the recording out, i.e., utilizing a 10 second display or less Intervals are all but impossible to assess using a standard 30 second screen width
Recording and Monitoring Techniques Measurement of the PR and QRS intervals can be accomplished by printing out the 10 second screen measure the intervals with a millimeter ruler and divide this measurement by the number of millimeters per second on the print out. Standard calipers can be used to determine regularity on these print outs It is possible to get intervals and test regularity by getting a stationary 10 sec window and using an index card. For example, make tick marks on the index card and move from R to R wave or P to P wave
Summary This presentation has shown the following: AASM guidelines for recording and reporting arrhythmias The basic anatomy and pathways of the cardiac conducting system The basic ECG wave forms and their relation to the cardiac cycle Presentation ti of normal ECG Presentation of a systematic way to analyze cardiac arrhythmias
Summary This presentation has shown the following: Examples of atrial, junctional, and ventricular arrhythmias and AV blocks A brief discussion of interventions for serious arrhythmias A discussion of recording and monitoring techniques and tips.