Dysrhythmias

the P wave and QRS

A block is usually a widening of the distance between

A. Determine the rate. B. Determine the regularity. C. Determine if there is a QRS for every P wave. D. Determine if there is a P wave for every QRS. Rationale: Determine rate, rhythm, and the presence of P waves and QRS complexes are important components of rhythm identification. There might not always be a U wave following every QRS.

As the nurse caring for a patient on a cardiac monitor, you understand which of the following steps are necessary to correctly identify the rhythm? (Select all that apply.) A. Determine the rate. B. Determine the regularity. C. Determine if there is a QRS for every P wave. D. Determine if there is a P wave for every QRS. E. Determine if there is a U wave for every QRS.

B. Electrolyte imbalances C. Myocardial hypertrophy D. Myocardial damage Rationale: Myocardial infarction or damage, cardiomyopathy or hypertrophy, and electrolyte disturbances can lead to dysrhythmias.

As the nurse, you know that the following can cause rhythm disorders: (Select all that apply.) A. Exercise B. Electrolyte imbalances C. Myocardial hypertrophy D. Myocardial damage E. Eating red meat

PR interval

Beginning of p wave to beginning of QRS. Time it is taking from SA impulse to Purkinje Fibers. 0.12 (3 small boxes) to 0.20 (5 small or 1 large box)

Pacemakers Maintain HR, CO and AV synchrony Pace at a specified rate when magnet is applied Are not defibrillators They do not stop fast heart rates Defibrillators All have pacemaker component, but may not be utilized if no pacing indication Treat sustained VT/VF with pacing (ATP) and or shocks Magnet application suspends detection for VT/VF and prevents treatment. It does not affect Pacing rates.

Differences between Pacemakers and Defibrillators

Potassium Chloride

Digoxin toxicity signs and symptoms- what do we give

time; voltage

Horizontal is ___. Vertical is ____.

Adenosine should be 6 mg administered rapidly over 1-3 seconds followed by a 20 ml NS bolus. If the patients rhythm does not convert out of SVT within 1 to 2 minutes, a second 12 mg dose may be given in similar fashion. A repeat dose of the 12 mg may be done X1. All efforts should be made to administer adenosine as quickly as possible.

How should adenosine be administered

Step 1: What is rate? EKG paper marked at 3-second intervals 1. Count number of complexes on 6 second strip and multiply by 10 (regular or irregular) 2. Count number of large boxes between two complexes and divide 300 by that number (only if regular) 3. Count number of small boxes between two complexes and divide 1500 by that number (only if regular) Step 2: Is the rhythm "regular"? Assess the R to R interval (ventricular) and P to P (atrial) Step 3 & 4: P waves and relationship to QRS Are p waves present, upright, round and smoothe? Is there one p wave or every QRS complex? Are they occurring regularly? Do all P-waves look similar? **Each small box = 0.04 seconds ****Each large box = 0.2 seconds Step 5: Determine interval durations Measure P-R interval: Normal 0.12-0.20 se Measure QRS duration: Normal 0.06-0.10 sec Measure QT interval: Normal 0.32 to 0.44 sec Step 6: Other Abnormalities Be sure ST segment is at level of isoelectric line

Interpreting Rhythm Strips

A. Medications for HR control B. Bleeding precautions C. Signs and symptoms of AF with RVR D. Cardioversion Rationale: Medications may be used for rate control. AF patients are typically on anticoagulants. A rapid ventricular response may occur with AF, resulting in adverse symptoms and decreased cardiac output. Cardioversion, not defibrillation, is sometimes indicated for AF.

Key patient teaching points for A-fib include which of the following? (Select all that apply.) A. Medications for HR control B. Bleeding precautions C. Signs and symptoms of AF with RVR D. Cardioversion E. Defibrillation

Affects a layer of the heart

NSTEMI=

0.12-0.20 Time which impulse travels from the SA node to the atria and downward to the ventricles

Normal PR interval is from ____seconds in length

0.06-0.10 Impulse from the Bundle of HIS throughout the ventricular muscles

Normal QRS is ___ seconds in length (or <3 small squares on the ECG paper)

0.10 SA Node fires, sends the electrical impulse outward to stimulate both atria and manifests as a P-Wave.

P wave is approximately ___ seconds in length

hyperkalemia

Peaked T-waves indicate ___

SA node (sinoatrial node) (located in the r atrium)

Primary "pacemaker of the heart"

Automatic Implantable Cardioverter-Defibrillators (AICD's)

Provides effective defibrillation for patients at risk for lethal dysrhythmias -Delivers shock if warranted -A pacemaker and ___can be combined into one device (biventricular implantable cardioverter defibrillator)

Atrial Fibrillation (A-Fib) Manifestations: Associated with heart failure, heart disease, HTN, hyperthyroidism r/t the ventricular rate. High vent rate causes decreased CO (hypotension, fatigue, dec LOC, U/O) Peripheral pulses irregular and variable amplitude Risk of thrombus formation! Management: Synchronized cardioversion (sync w/ QRS to avoid VF) Meds to reduce ventricular rate-beta blockers, calcium channel blockers (ie. diltiazem), antiarrhythmics (ie. amiodarone), digoxin. Anticoagulant to prevent stroke!!

Rate: 100-180 bpm Rhythm: irregularly irregular P to QRS: variable, p waves undistinguishable PR interval: unable to measure QRS complex: 0.06-0.10

Ventricular tachycardia (V-tach) Manifestations: 3 or more consecutive PVCs (run of PVCs) Myocardial ischemia and infarction most common Nonsustained: ℅ palpitation, SOB Sustained: Hemodynamic instability Pulseless: No pulse, no breathing Management: Treat if sustained (more than 30 seconds) symptomatic or w/heart disease If pulseless treatment is same as ventricular fibrillation CPR, defibrillation, epinepherine,vasopressin, amiodarone

Rate: 100-250 Rhythm: regular P to QRS: p waves not identifiable PR interval: unable to measure QRS complex: >0.12 (wide and bizarre looking)

Sinus Tachycardia Manifestations: Rapid pulse, feeling heart racing, SOB, dizziness. Management: (symptomatic) Carotid massage, Beta Blockers Treat underlying cause. If at rest, this is not normal! Hypovolemia Fever Pain/anxiety Anemia

Rate: 101-150 bpm Rhythm: regular P to QRS: 1 to 1 (if very fast, p waves may be hidden) PR interval: 0.12-0.20 QRS complex: 0.06-0.10

Torsades de Pointes French term that signifies the "twisting of the points" May wax and wane in amplitude and may "flip" or "twist" on its electrical axes. Similar to ventricular tachycardia Caused by hypomagnesemia or by antiarrhythmic drugs Treatment: aimed at shortening the QT interval Isoproterenol infusion, cardiac pacing, Atropine, *magnesium sulfate

Rate: 150-250 Form of ventricular tachycardia QRS Complexes "Twist" Rhythm: Irregular

Paroxysmal Supraventricular Tachycardia (PSVT) Manifestations: Causes: Fever, sepsis, hyperthyroidism, heart disease, MI ℅ racing heart, anxiety, dyspnea, dizziness, anginal pain, diaphoresis, fatigue and polyuria (d/t inc CO) Management: Treat if symptomatic Vagal maneuvers (valsalva, carotid massage, suction) Oxygen Adenosine (IVP) Synchronized cardioversion (sync with QRS, avoid VF)

Rate: 150-280 bpm Rhythm: regular P to QRS: p waves may not be identifiable as hidden in previous t wave PR interval: unable to measure QRS complex: 0.06-0.10

Sinus Arrhythmia Manifestations: None Management: Doesn't usually cause any impairment and is not usually treated.

Rate: 60-100 bpm Rhythm: irregular, coincides with respiration P to QRS: 1 to 1 PR interval: 0.12-0.20 QRS complex: 0.06-0.10

normal sinus rhythm (NSR)

Rate: 60-100 bpm Rhythm: regular P to QRS: 1 to 1 PR interval: 0.12-0.20 QRS complex: 0.06-0.10

Sinus Bradycardia Manifestations: May result from vagal (parasympathetic) or injury to SA node (ischemia). Increased ICP, AMI, hypothermia, drugs, acidosis. Normal in athletes or sleep Often asymptomatic, but if so, decreased CO symptoms such as hypotension, decreased LOC, syncope. Management: Only if symptomatic Oxygen, IVP atropine 0.5 to 1.0 mg Pacemaker (if profound or chronic)

Rate: <60 bpm Rhythm: regular P to QRS: 1 to 1 PR interval: 0.12-0.20 QRS complex: 0.06-0.10

Atrial Flutter Manifestations: Causes: SNS stimulation, heart disease, MI, PE. ℅ palpitations, if vent rate rapid, then s/s of dec CO (hypotension, dizziness, cool/clammy skin, dec U/O) Management: Medications to slow ventricular rate (B-blocker or Ca channel blocker), followed by amiodarone (antidysrhythmic) Synchronized cardioversion (sync w/ QRS to avoid VF)

Rate: Usually 101-150 bpm Rhythm: regular (p waves sawtooth shape) P to QRS: 2:1, 4:1, 6:1 PR interval: unable to measure QRS complex: 0.06-0.10

Ventricular fibrillation (V-fib) Manifestations: Cardiac arrest, death within 4 minutes Triggered by myocardial ischemia/infarction No pulse, no breathing Management: CPR, defibrillation, epinephrine, vasopressin, amiodarone Amiodarone administration 300 mg IV/IO push (if no conversion) 150mg IV/IO push (after conversion) Maintenance drip: 360 mg IV over 6 hours (1mg/min) → then 540 mg IV over 18 hours (0.5mg/min)

Rate: too rapid to count Rhythm: grossly irregular P to QRS: p waves not identifiable PR interval: unable to measure QRS complex: not able to measure, varying in size and shape

Premature Atrial Complexes (PACs) (ectopic atrial beats) Manifestations: Often asymptomatic If symptomatic-palpitations, SOB, anxiety, etc. May precede a dysrhythmia Management: Treat the cause-hypoxia, ischemia, electrolyte imbalance, drug toxicities, stimulants. Advise to reduce alcohol & caffeine intake, reduce stress, stop smoking

Rate: variable Rhythm: irregular P to QRS: 1 to 1 PR interval: 0.12-0.20, may be prolonged QRS complex: 0.06-0.10

Premature Ventricular Contractions (PVCs) (ectopic ventricular beats) Manifestations: Not significant in absence of heart disease Frequent or recurring may precursor to lethal arrhythmia, caused by anxiety stress, or stimulants, or alcohol, hypoxia, acidosis, electrolytes or reperfusion. Greatest occurrence after MI Management: Treat only if symptomatic or w/heart disease Treat the cause No stimulants (caffeine, nicotine) B-blocker or antiarrhythmic

Rate: variable Rhythm: irregular, PVC interrupts rhythm and then compensatory pause P to QRS: no p before PVC PR interval: unable to measure QRS complex: >0.12 (wide and bizarre looking)

Team safety (ALL CLEAR)

Regardless of cardioversion or defribulation, the person with the paddles is responsible for_

U wave

Represents Purkinje fiber repolarizations and is rarely seen Can be seen with certain drug toxicities (digoxin toxicity) and electrolyte disturbances (hypokalemia)

Myocardial infarction (MI) HTN Heart valve disease Heart failure (HF) Cardiomyopathy (CM) Infections Diabetes mellitus leep apnea Heart surgery (and procedures) Electrolyte disturbances Recreational drug use Drug toxicities such as digoxin toxicity

Risk Factors for Developing a Dysrhythmia

ST segment elevation myocardial infarction (through all the muscle layers of the heart- more extensive damage)

STEMI=

hypokalemia; myocardial ischemia

T wave depression indicates ___ it can also be associated with ___ the patient is symptomatic

C. Symptomatic heart block Rationale: Transcutaneous pacing may be used in symptomatic block, causing bradycardia. VF and VT without a pulse require defibrillation. VT with a pulse and atrial fibrillation may require cardioversion if the patient is symptomatic.

Transcutaneous pacing should be considered for which of the following dysrhythmias? A. VF B. VT C. Symptomatic heart block D. AF

What are the three most common complications of CABG that would lead to decreased cardiac output? Pump failure, cardiac tamponade & hemorrhage. What assessment findings would correlated with each of the three complications that lead to decreased cardiac output? Pump failure (UOP<30 ml/hr x 2 hours, S3 gallop, JVD, etc.) Cardiac Tamponade (Decrease in CT drainage, muffled heart tones, decreased pulses, marked hypotension Hemorrhage (> 70 ml/hr in CT) What independent nursing interventions and collaborative therapies might you anticipate for each of the three complications? a. Pump failure: HOB up, limit activity, make sure that O2 is on b. Cardiac tamponade: Assess CT drainage device, assess UOP c. Hemorrhage: HOB flat or at 10 degrees; assess vital signs frequently; assess LOC, heart rhythm

What are the three most common complications of CABG that would lead to decreased cardiac output? What assessment findings would correlated with each of the three complications that lead to decreased cardiac output? What independent nursing interventions and collaborative therapies might you anticipate for each of the three complications?

D. No commonalities Rationale: There are no commonalities. There is a connection between the atria and ventricles in second degree blocks. In third degree blocks, the atria and ventricles are working independently.

What do second-degree and third-degree heart blocks have in common? A. Wide QRS complexes B. Narrow QRS complexes C. Dropped QRS complexes D. No commonalities

Magnet

What is used to turn pacemaker up or down?

***Atropine 0.5 mg IV

What woud you do for your patient with a HR of 30 bpm?

Pull the patient up by their armpits (can pull out of place)

When getting a patient from pacemaker surgery the nurse must NOT

C. It is reflected in the waveforms on the electrocardiogram. Rationale: The electrical conduction system is controlled by the movement of charged ions across the cell membrane, has a negative resting membrane potential, and is composed of cells with the property of automaticity, which is reflected in the waveforms on the electrocardiogram.

Which is true of the electrical conduction system of the heart? A. It is primarily controlled by the movement of uncharged ions. B. It has a positive resting membrane potential. C. It is reflected in the waveforms on the electrocardiogram. D. It requires cells that respond only to stimulus from the autonomic nervous system.

D. Ventricular fibrillation Rationale: VF requires defibrillation. Atrial tachycardia or fibrillation or ventricular tachycardia with a pulse may require cardioversion if the patient is symptomatic.

Which of the following dysrhythmias requires defibrillation? A. Atrial tachycardia B. Atrial fibrillation C. Ventricular tachycardia with a pulse D. Ventricular fibrillation

Asystole Be sure to verify that indeed the patient is asystolic in more than one lead CPR!!! CPR!!! CPR!!! Try to determine the cause and fix it!!

absence of contractions of the heart

QRS complex

depolarization & contraction of the ventricles. 0.06 (1.5 small boxes) to 0.10 (2.5 small boxes) sec

P wave

depolarization and contraction of the atria. Smooth, rounded and upright.

ST segment

end of QRS to beginning of T wave. Same plan as isoelectric line. Elevated = infarct. Depressed = injury.

pacemaker A heart rate less than 60 bpm indicates pacemaker failure Indications - Symptomatic second degree heart blocks, 3rd Degree AV Block, Symptomatic/unstable bradycardia

pulse generator used to provide an electrical stimulus to the heart when fails to generate or conduct its own stimulus at a rate that will maintain cardiac output

T wave

repolarization of the ventricles. Inverted with injury. Peaked with hyperkalemia.

0.04; 0.2

when looking at a strip **Each small box = __seconds ****Each large box = ___seconds