EKG, Sinus Rhythms & Heart Block

Normal PRI

0.12-0.20 sec 3 small boxes to 5 small boxes (5 small boxes = 1 big box)

Step 3 - P wave

1. Are P waves present? 2. Are P waves occurring regularly? 3. is there one P wave present for every QRS complex present? 4. Are the P waves smooth, rounded, and upright in appearance, or are they inverted? 5. Do all P waves look similar?

PR Interval questions

1. Are the PR intervals greater than 0.20 seconds? 2. Are the PR intervals less than 0.12 seconds? 3. Are the PR intervals consistent across the EKG strip?

Sinus Tachycardia Nursing Interventions

1. Assess patient, are they symptomatic? stable? 2. Give oxygen and monitor oxygen saturation 3. Monitor blood pressure and heart rate 4. Start an IV if not already done. 5. Notify the MD

What are the five steps involved in interpreting EKG Rhythm Strips?

1. Heart Rate 2. Heart Rhythm 3. P wave 4. PR interval (aka PRI) 5. QRS complex (6. T wave. I added this one)

Atrial Flutter - 5 steps

1. Rate - Atrial is 250-500; ventricular is variable. 2. Rhythm - Atrial is regular, ventricular may be irregular 3. Normal P waves are absent; flutter waves (f waves) (sawtooth pattern) 4. PRI is not measurable 5. All QRS complexes do look alike, QRS is .06-.12 sec

Normal Sinus Rhythm

1. Rate is between 60 and 100 bpm 2. Atrial and Ventricular rhythms are regular. 3. P wave is present before every QRS; P waves are upright and uniform. 4. PR interval is between 0.12-0.20 seconds (3-5 small squares). 5. QRS complexes look alike and they are 0.06-0.12 seconds. QT is <0.40 or two large boxes.

Normal QT

<0.40 10 small boxes two big boxes

Normal QRS

<10 2 1/2 small boxes or less

Causes of Atrial Flutter

>60 years old, mitral valve disorder, thick heart muscle, ischemia (low blood flow), cardiomyopathy, COPD, emphysema

Premature Atrial Contractions (PAC's)

A PAC is not a rhythm, it is an ectopic beat that originates from the atria. It's a normal beat that just occurs early. Rate: usually regular, but depends on underlying rhythm. Rhythm: irregular as a result of the PAC P wave present, usually upright but premature and abnormal shape. PRI is normal, QRS normal and alike.

Step 2 - Rhythm

A sequential beating of the heart as a result of the generation of electrical impulses. Can be classified: -Regular: R-R intervals are regular ---intervals vary by <0.06 seconds or 1.5 small boxes. -Irregular: R-R intervals are not regular ---Intervals are >0.06 seconds or 1.5 small boxes

Medical Tx for Sinus Tachycardia

Aimed at finding and treating underlying cause

Supraventricular Rhythms

All originate in the atrium, and they all have some type of P wave

Cardiac Output CO

Amount of blood pumped out by the LEFT VENTRICLE in one minute. Normal CO is 4-8 L/min. CO=SV x HR

After-load

Amount of pressure against which the left ventricle must work during systole to open the aortic valve

Locating the Infarction

Anterior - V1, V2, V3, V4 Lateral - I, AVL Inferior - II, III, AVF Posterior - V1 & V2 - R waves with ST depression.

Dysrhythmia

Any disorder of the heartbeat; also called an arrhythmia. Results from: -a disturbance in the relationship between electrical conductivity and the mechanical reponse of the myocardium. -a disturbance in impulse formation (either from an abnormal rate or from an ectopic focus) -a disturbance in impulse conduction (delays and blocks) -combination of several mechanisms (text, pg 719)

What can put someone at risk for developing Sinus Bradycardia?

Anything that lowers CO

Atrial Fibrillation Nursing Interventions

Assess Patient, give oxygen, start IV, notify MD, prepare for cardioversion

PAC Nursing Interventions

Assess and monitor your patient.

Atrial Flutter Nursing Interventions

Assess patient, give oxygen, start IV, notify MD, prepare for cardioversion.

Nursing Interventions for Sinus Pause/Arrest

Assess pt, give oxygen & monitor 02 sat, monitor BP and HR, start IV, notify MD. ACLS: treat the cause (med, electrolyte imbalance, natural deterioration of the cardiac system). May require pace for tx if pt is symptomatic.

Supraventricular Tachycardia (SVT) Nursing Interventions

Assess your patient. Are they symptomatic? Give oxygen. Have pt. do vagal maneuvers like coughing or vasalva (bearing down). Start an IV and hang NS. Notify MD, prep for cardioversion.

Nursing Interventions for Sinus Bradycardia

Assess your pt - are they symptomatic? Give oxygen, monitor oxygen saturation. Monitor BP and HR. Start IV if not already done, and notify the MD.

4 most common atrial arrhythmias include:

Atrial Flutter (rate varies, usually regular, saw-toothed pattern). Atrial Fibrillation (rate varies, always irregular) Supraventricular Tachycardia (>150 bpm) Premature Atrial Complexes (PAC's)

P Wave

Atrial depolarization

What is the medical tx for sinus bradycardia?

Atropine (to speed it up), pacing if the pt. is hemodynamically compromised. Tx may vary according to sx.

Risks associated with Sinus tachycardia

CO may fall due to inadequate ventricular filling time, myocardial oxygen demand increases, can precipitate myocardial ischemia or infarction

S/S of Sinus Pause/Arrest

Can be asymptomatic. Syncope, dizziness, change in LOC, bradycardia.

Heart Blocks

Can occur anywhere in the heart

Causes of PAC's

Can occur in healthy pts without heart disease. Also stress, stimulants, HTN, valvular condition, infectious diseases, hypoxia

Medical Tx for Atrial Flutter

Cardioversion is the treatment of choice. Antiarrhythmics such as procainamide can convert the flutter. (?) SLOW THE VENTRICULAR RATE by usuing diltiazem, verapamil, digitalis, or beta blocker Heparin to reduce incidence of thrombus formation

Risks associated with Atrial Flutter

Clot formation in atria (atria not completely emptying), can lead to stroke or PE. Dramatic drop in cardiac output

Risks associated with afib

Clot formation in atria because the blood is just sitting there; it's not emptying properly. Can lead to Stroke, PE. Dramatic drop in CO.

Step 1 - Heart Rate

Count the number of electrical impulses as shown by PQRST complexes within one minute. ATRIAL RATE - count the number of P waves VENTRICULAR RATE - count the number of QRS compleses

Rate determination chart method for determining HR

Count the spaces between R-R. Look at a chart reference for this, say it's 15 spaces, the chart will tell you that it's 100 bpm.

Causes of Sinus Tachycardia

Damage to heart tissues from heart disease, hypertension, fever, stress, excessive alcohol, caffeine, nicotine, or recreational drugs like cocaine. Side effect of meds, pain response, electrolyte imbalance, hyperthyroidism.

Myocardial Infarction

Death of cardiac tissue due to impaired flow of blood/oxygen, usually due to a blockage of coronary arteries.

Multifocal Atrial Tachycardia (SVT)

Different P waves (may not see P waves), but each P wave produces a QRS. HR is >100 bpm. (Slikde 30 - New Cardiology)

S/S of Sinus Tachycardia

Dizziness, SOB, lightheadedness, rapid pulse rate, heart palpitations, chest pain, syncope

Supraventricular Tachycardia SVT

Encompasses all fast (tachy) dysrhythmias in which heart rate is >150 bpm. Atrial and ventricular RATES are 150-250 bpm. P wave is not discernible as it gets lost in the QRS. PRI not discernible either. QRS is normal (.06-.12 sec), all look alike.

Sinus Tachycardia

Fast heart beat r/t rapid firing of the SA node. Rate - 101-160 bpm Rhythm - atrial and ventricular are regular P wave before each QRS, P waves are upright and uniform PRI = 0.12-0.20 (3-5 small boxes) All QRS's are created equal, length is normal at 0.06-0.12 (1.5-3 small boxes).

Interpreting EKG Rhythm Strips

First and foremost, always ASSESS YOUR PATIENT. Apply the five-step systematic approach

Medical Tx for SVT

For patients who are stable and asymptomatic, just have them do a vagal maneuver like bearing down. You can also give adenosine. If pt. is unstable, you can give adenosine.

Causes of Sinus Arrythmia

Heart disease, moderate to extreme stress, excessive consumption of stimulants like caffeine, nicotine and alcohol; intake of medications like diet pills, as well as cough and cold medicines.

What can cause Sinus Bradyardia?

Hypoglycemia, hypothermia, hypothyroidism, previous cardiac history, medications, toxic exposure, MI - Inferior wall involving right coronary artery

Risks associated with SVT

If it lasts long enough, heart failure can set in.

Cardiac Damage Triad

Ischemia, Injury, Infarction

The six-second method to determining heart rate

Look at the number of QRS complexes and multiply by 10

Sinus Tachycardia - ACLS Protocol

Look for the cause of the tachycardia and treat it. -Fever: give acetaminophen or ibuprofen. -Stimulants: stop use (caffeine, OTC meds, herbs, illicit drugs) -Anxiety: give reassurance or anti-anxiety medication -Sepsis, Anemia, HoTN, MI, HF, Hypoxia For Narrow QRS complexes: consider vagal maneuvers, adenosine, beta blocker, CCB, or synchronized cardioversion For Wide QRS Complexes: consider anti-arrhythmic such as procainamide, amiodarone or sotalol.

Ischemia

Low blood supply of oxygen; manifests as inverted T waves.

Injury to Myocardium

Manifests as ST elevation. Can be acute or recent.

Step 4 - PR Interval

Measured from the start of P to the start of Q. This measures the time from the start of atrial contraction to the start of ventricular contraction. Remember that normal PRI is 0.12 to 0.20 seconds, or 3-5 small squares.

Risks associated with PAC's

Most of these are benign and don't really have any risks. Some may be a sign of an underlying heart condition.

Switching gears

Next slides from Basic EKG Refresher PDF

Medical Tx for PAC

No treatment necessary if pt. is asymptomatic. Treat the underlying cause if you can identify it. Give meds: beta blockers, CCB's.

3rd Degree (Complete) AV Block

None of the sinus impulses are reaching the ventricles. The ventricles then depolarize themselves. Atria and ventricles are pacing on their own, independent of each other, and blood is not effectively being pumped out. PR interval is never the same; you won't find a consistent measurement across the strip.

First Degree AV Block

Normal P QRS T sequence PRI >0.20 and is always the same. This is essentially a normal sinus rhythm with a longer PR interval. It's greater than 0.2 instead of 0.12-.20. (it's taking longer for signal to go from sa node to av node). Most pts are asymptomatic, never seen anyone with an issue. Rate of the rhythm of this block can range from brady to normal.

Step 5 - QRS Complex

Normal is 0.06-0.12 seonds (1.5 to 3 small boxes). 1. Are the QRS complexes > 0.12 seconds? 2. Are the QRS complex <0.06 seconds? 3. Are the QRS complexes similar in appearance across the EKG strip?

What are the five most common variations of a sinus rhythm?

Normal sinus rhythm (60-100 bpm) Sinus Bradycardia (<60 bpm) Sinus Tachycardia (>100 bpm) Sinus Arrhythmia (60-100 bpm) Sinus Pause/Arrest

U Wave

Not usually visible on EKG strips; if you can see it, it generally follows the T wave. Picture on page 44. Smaller than T wave, cause not understood, may indicate hypokalemia.

Medical Tx for Sinus Pause/Arrest

Only treated if pt. is symptomatic. Give atropine or a pacemaker.

One complete cardiac cycle in ECG terms

P, QRS, and T wave

2nd Degree AV Block Type 2

PRI is always constant, and occasionally the P wave has a dropped QRS. You can see this on the strip. Most pts. are very bradycardic, this does require tx with a pacemaker. Atropine can be given short-term, not good for longterm treatment. AKA Mobitz 2.

2nd Degree AV Block - Type 1

PRI progressively becomes longer and longer until a QRS complex is dropped. Some sinus impulses are reaching the ventricles, and some are not because they are blocked. Pt. doesn't get enough bloodflow, and their LOC can change. This needs to be controlled, so a pacemaker would be the treatment of choice. AKA Mobitz 1 or Wenkebach.

S/S of Atrial Flutter

Palpitations, SOB, anxiety, weakness, angina, syncope

S/S of Supraventricular Tachycardia (SVT)

Palpitations, chest discomfort (pressure, tightness, pain), lightheadedness or dizziness, syncope, SOB, a pounding pulse, sweating, tightness or fullness in the throat, tiredness (fatigue), excessive urine production. QUESTION - WHY POLYURIA WITH SVT?

S/S of PAC's

Palpitations, skipped beat

T Wave

Produced by ventricular repolarization or relaxation. Commonly seen as the first upward or positive deflection following the QRS complex.

Bundle Branch Blocks - Right or Left (RBB or LBB)

QRS > 0.12 One ventricle depolarizes after the other

Sinus Bradycardia (SB)

RATE - <60 bpm P WAVE - sinus QRS - normal (0.6-0.12) CONDUCTION - PR normal or slightly prolonged at slower rates. RHYTHM - regular or slightly irregular

Sinus Tachycardia (ST)

Rate - >100, usually <170 P wave is present before every QRS. QRS is normal.

Medical Tx of Atrial Fibrillation

Rate control, (slow ventricular rate to 80-100 beats/min) with digoxin, beta blockers, CCB's (verapamil). Antithrombotic therapy, correction of rhythm with chemical or electrical cardioversion.

Risks associated with Sinus Arrhythmia

Reduced CO

Cardiac Cycle

Represents the actual time sequence between ventricular contraction and ventricular relaxation

Coronary Arteries

Right coronary artery, left coronary artery

3rd Degree (Complete) AV Block - S/S and Treatment

S/S: cyanosis due to low perfusion, slow cap refill, low BP, weak pulse, change in LOC (confusion). This is usually CAUSED by an MI. TREATMENT: A pacemaker is your best bet at this point. Atropine won't work because the signal won't travel evenly throughout the heart.

Systole

Simultaneous contraction of the ventricles

Causes of Supraventricular Tachycardia (SVT)

Stimulants, hypoxia, stress or over-exertion, hypokalemia, atherosclerotic heart disease

Risks associated with Sinus Pause/Arrest

Sudden cardiac death, although this is rare. Syncope, fall, thromboembolic events (including stroke), CHF, and Atrial tachyarrhythmias such as atrial flutter or fibrillation.

S/S of Bradycardia

Syncope (fainting), dizziness, chest pain, SOB, exercise intolerance, cool clammy skin

Diastole

Synonymous with ventricular relaxation, this is when the ventricles fill passively from the atria to 70% of blood capacity.

AV Blocks

Temporary or complete dissociation of stimuli from atrium to ventricle. Look for a PRI >0.20. There are three types: First degree, second degree, and third degree.

Sinus Arrest or Pause

The transient absence of sinus P waves that last from 2 seconds to several minutes. Rate - variable, depending on frequency. Rhythm - Irregular, when sinus arrest is present P is present before QRS if QRS is present. P waves upright and present when they are there. PRI = 0.12-0.20 sec

Sinus Rhythms

These are rhythms that originate in the SA node.

Causes of Sinus Pause/Arrest

This can occur in individuals with healthy hearts during sleep. Other causes: Myocarditis, cardiomyopathy, MI, digitalis toxicity, elderly age, vagal stimulation.

Sinus Bradycardia

This is a regular but slow heartbeat at <60 bpm; normal with athletes, during sleep, or in response to a vagal. RATE: <60 bpm RHYTHM: atrial and vent rhythms are regular. P before QRS? yes. P waves upright and uniform? yes. PR length? 0.12-0.20 seconds QRS complexes even, 0.06-0.12 (normal).

Sinus Arrhythmia

This is almost the same as sinus rhythm. Everything is normal except for the rhythm. The rhythm is irregular; it varies more than 0.08 seconds. (Normal means that they would vary by <0.06 seconds.)

Artifact

This is when interference makes the baseline very squiggly and it makes it hard to read the strip. 4 causes: Pt. movement, loose or defective electrodes (leads to fuzzy baseline), improper grounding (60 cycle interference [?]), Faulty EKG apparatus.

S/S of Sinus Arrhythmia

This one is usually asymptomatic

Medical Tx for Sinus Arrhythmia

Tx is generally not required if pt. is asymptomatic. If pt. is symptomatic, find and treat the underlying cause.

Be careful with a LBB

Unable to diagnose an acute MI with the presence of a Left Bundle Branch Block. So in the presence of a Left Bundle Branch Block, especially if it is new, an acute MI must be ruled out.

T Wave

Ventricular Repolarization

QRS

Ventricular depolarization

Pre-load

Volume and stretch of the ventricular myocardium at the end of diastole (aka ventricular relaxation)

Stroke Volume (SV)

Volume of blood being pumped out of ventricles in a single beat or contraction. Normal stroke volume is 60-130 mL.

Atrial Rhythms

When the SA node fails to generate an impulse, atrial tissues or intermodal pathways may initiate an impulse.

Atrial Flutter

a coordinated rapid beating of the atria. Atrial flutter is the second most common tachyarrhythmia. Characterized by F waves in a sawtooth pattern.

Atrial Fibrillation

atrial rate 350-400, ventricular rate is variable. Rhythm irregularly irregular. P waves absent, replaced by F waves. PRI not discernible. QRS normal, all look alike. Atria are quivering but not contracting. Ventricles don't receive regular impulses and contract out of rhythm. MOST COMMON ARRHYTHMIA, 85% of people with it are >65 years.

S/S of afib

heart palpitations, irregular pulse with feels too rapid or too slow, racing, pounding, or fluttering. Dizzy, lightheaded, fainting, confusion, fatigue, trouble breathing, difficulty breathing when lying down, sensation of tightness in the chest.

Causes of afib

hypoxia, hypertension, CHF, coronary artery disease, dysfunction of the sinus node, mitral valve, disorders, rheumatic heart disease, pericarditis, hyperthyroidism, excessive alcohol or caffeine consumption.

Cardioversion

the delivery of a direct countershock to the heart, synchronized to the QRS complex. Indications: elective tx of atrial dysrhythmias, supraventricular tachycardia, and ventricular tachycardia with a pulse. Tx of choice for pts who are symptomatic. (ATI)

Debfibrillation

the delivery of an unsynchronized, direct countershock to the heart. This stops all electrical activity of the heart, allowing the SA node to take over and reestablish a perfusing rhythm. Indications: ventricular fibrillation or pulseless ventricular tachycardia. (ATI)