Complex Health: Exam 1

Cardiac Electrical Activity

• All cardiac cells have the potential to generate electrical impulses.

• Ectopy: Stimuli generated outside of the normal conduction pathway.

SA Node Intrinsic Rate is…

60 to 100 bpm

AV Node Intrinsic Rate is…

40 to 60 bpm

Bundle Branches Intrinsic Rate is…

25 to 40 bpm

Cardiac Cycle (picture)

Understanding ECG Graph Paper

Mechanics:

• Used to standardize tracings.

• Vertical boxes measure voltage/amplitude (T wave/ST elevation)

Sizing:

• 1 small box = 0.04 seconds

• 1 large box = 0.20 seconds = 5 small boxes

• 5 large boxes = 1 second

• 30 large boxes = 6 seconds

Interpretation of Rhythms

Steps of Rhythm:

• Rhythm — Is it regular or irregular?

• Heart Rate — Is it fast or slow?

• Evaluate the P wave

• Measure the PR interval

• Evaluate/measure the QRS (including the QT segment)

• Evaluate the ST segment — Is it at baseline?

• Evaluate the T wave — Upright? Peaked or flattened?

Sinus Rhythms

Originate from Sinus Node:

• Normal Sinus

• Sinus Bradycardia

• Sinus Tachycardia

• Sinus Arrhythmia

Normal Sinus Rhythm (NSR): Criteria

• Rate: 60 to 100 (ventricular and atrial)

• Rhythm: Regular

• P waves: Uniform and upright

• P to QRS Ratio: 1:1

• PR Interval: 0.12 to 0.20 seconds

• QRS Complex: Less than 0.12 seconds

Sinus Bradycardia: Criteria

• Rate: Less than 60 bpm in the adult (ventricular and atrial)

• Rhythm: Regular

• P waves: Normal and consistent, in front of the QRS

• P to QRS Ratio: 1:1

• PR Interval: Consistent, between 0.12 and 0.20 seconds

• QRS Complex: Less than 0.12 seconds

Sinus Bradycardia: Causes

Lower Metabolic Needs:

• Sleep

• Athletic training

• Hypothermia

Vagal Stimulation:

• Vomiting

• Suctioning

• Bowel movements

Medications:

• Calcium channel blockers

• Beta-blockers

Other:

• Increased intracranial pressure

• Coronary artery disease

• Inferior wall MI

• Decompensated heart failure

• Electrolyte deficiencies

Sinus Bradycardia: Clinical Manifestations & Diagnostics

Clinical Manifestations:

• Lightheadedness or dizziness (especially with exertion)

• Easy fatiguability

• Syncope (fainting) or near-syncope

• Dyspnea (shortness of breath)

• Chest pain or discomfort

• Confusion

Diagnostics:

• Vital signs

• 12-lead ECG

• Chief complaint/complete history and physical examination

• Lab work

• Echocardiogram (ultrasound of the heart)

Sinus Bradycardia: Treatments

Treatment:

• Fix the problem/correct the cause.

• Stop the meds, warm the patient, and stop nausea/vomiting.

If Symptomatic:

1. Atropine 1 mg IV bolus, repeated every 3 to 5 minutes until a maximum dose of 3 mg.

   • An order is typically needed, except for emergencies; Have to be ACLS trained.

   • How do you know when to stop giving the atropine?—You have reached your max dose or you patient is now stable (Pulses, HR, BP, etc.)

2. If ineffective, apply pacing pads to the skin for transcutaneous pacing. (a little more invasive)

   • Provide medication/sedation prior—it shocks!

3. If that is ineffective, administer epinephrine and/or dopamine.

Sinus Tachycardia: Criteria

• Rate: Greater than 100 bpm in the adult (ventricular and atrial)

• Rhythm: Regular

• P Waves: Normal and consistent, in front of the QRS

• P to QRS Ratio: 1:1

• PR Interval: Consistent, between 0.12 and 0.20 seconds

• QRS Complex: Less than 0.12 seconds

Sinus Tachycardia: Causes

Physiologic:

• Acute blood loss

• Anemia

• Severe dehydration

• Shock

• Hypovolemia

• Heart failure

• Pain

• Hypermetabolic states

• Fever

• Exercise

Psychological Stress:

• Anxiety

Medications:

• Cold meds — pseudoephedrine

• Bronchodilators — albuterol

• ADHD — Ritalin and Adderall

• Antidepressants — Cymbalta

• Thyroid meds — Synthroid

Other Stimulants:

• Caffeine, nicotine

• Amphetamines, cocaine, ecstasy

Autonomic Dysfunction:

• Postural Orthostatic Tachycardia Syndrome (POTS) — Tachycardia with position changes but with an adequate change in BP to perfuse the brain.

Sinus Tachycardia: Clinical Manifestations & Diagnostics

Clinical Manifestations:

• Drop in blood pressure upon standing (orthostatic hypotension)

• Palpitations

• Fatigue

• Exercise intolerance

• Blurred vision

• Dizziness

• Chest pain

• Fainting

• Lightheadedness

• Shortness of breath

• Sweating

• Weakness

Diagnostics:

• Vital signs

• 12-lead ECG

• Chief complaint/complete history and physical examination

• Lab work

• Echocardiogram (ultrasound of the heart)

Sinus Tachycardia: Treatment (treat the problem!)

Physiologic:

• Acute blood loss, anemia — Find the source, replace the loss.

• Dehydration — Fluids/eliminate the cause; provide fluid replacement.

• Fever — Use antipyretics.

• Pain — Use pharmacological and non-pharmacological pain relief.

• Shock — Identify the type and treat the cause.

Psychological Stress:

• Make lifestyle changes.

• Seek mental health treatment.

Medications:

• Change or avoid certain medications. (amphetamines, cold medicine, etc.)

• Use beta-blockers (e.g., Metoprolol, Lopressor, etc.)

• Use calcium channel blockers (e.g., Amlodipine, Diltiazem, etc.)

Other Stimulants:

• Eliminate the source (caffeine, alcohol, smoking, drugs, etc.)

If Unresponsive to Other Treatments:

• Possible cardiac ablation therapy.

Atrial Rhythms

Originate from Foci within the Atria:

• Premature Atrial Complexes (PACs)

• Atrial Fibrillation (A-Fib)

• Atrial Flutter (A-Flutter)

Premature Atrial Contractions (PACs)

Signs/Symptoms:

• The patient may say, “My heart skipped a beat.”

• Possible pulse deficit (difference between apical and radial pulse rate).

Causes:

• Caffeine, alcohol, nicotine

• Stretched atrial myocardium (e.g., as in hypervolemia)

• Stress/anxiety

• Electrolyte imbalances

• Atrial ischemia, injury, or infarction

Treatment:

• Treat the underlying cause:

  • Replace electrolytes

  • Reduce stress/anxiety

  • Dietary changes

• Asymptomatic = no treatment

• Symptomatic = Amiodarone and beta-blockers

Atrial Fibrillation (A-Fib): Criteria

• Rate: Atrial — 300 to 600 bpm; Ventricular — Variable, but between 60 to 100 bpm

• Rhythm: Highly irregular

• P Waves: No discernible P waves; irregular, undulating waves are referred to as fibrillatory or f waves

• P to QRS Ratio: Not discernible

• PR Interval: Absent; unmeasurable due to lack of P waves

• QRS Complex: Usually normal

A-Fib: Risk Factors

• Increasing Age

• Hypertension

• Diabetes

• Obesity

• Valvular heart disease

• Heart failure

• Obstructive sleep apnea

• Alcohol abuse

• Hyperthyroidism

• Myocardial infarction

• Smoking

• Exercise

• Cardiothoracic surgery

• Increased pulse pressure

• European ancestry

• Family history

A-Fib with RVR (Rapid Ventricular Response): Criteria

• Rate: Atrial — 300 to 600 bpm; Ventricular — Variable, between 100 to 200 bpm

• Rhythm: Highly irregular

• P Waves: No discernible P waves; irregular, undulating waves (fibrillatory or f waves)

• P to QRS Ratio: Many:1

• PR Interval: Absent; unmeasurable due to lack of P waves

• QRS Complex: Usually normal

Atrial Flutter (A-Flutter): Criteria

• Rate: Atrial — 250 to 400 bpm; Ventricular — 75 to 150 bpm

• Rhythm: Atrial regular; Ventricular usually regular but may be irregular due to changes in AV conduction

• P Waves: Saw-toothed, referred to as F waves

• P to QRS Ratio: 2:1, 3:1, or 4:1

• PR Interval: Multiple F waves make determination difficult

• QRS Complex: Usually normal

A-Flutter/A-Fib Comparison Chart + Interventions

A-Flutter:

• Unstable patients: Prepare for cardioversion.

• Administer medication: Anticoagulant

A-Fib:

• Unstable patients: Prepare for cardioversion.

• O2 therapy

• Anticoagulants: To prevent emboli.

• Administer cardiac medications (beta-blockers, calcium channel blockers, digoxin)

A-Fib/A-Flutter: Clinical Manifestations

Signs:

• Irregular pulse

• "Pulse deficit"

• Variable heart sounds

• May present with a murmur or pulmonary edema

Symptoms:

• Palpitations

• Shortness of breath

• Dizziness/lightheadedness

• Chest pain

• Fatigue

• Dyspnea on exertion

Important to Know:

• May be asymptomatic

• Patients are 5 times more likely to suffer a stroke (approximately 15% are caused by A-fib)!!

A-Fib/A-Flutter: Management

Prevention: Anticoagulants:

• Warfarin (Coumadin)—1st line; frequent lab monitoring—PT/PTT/INR

• Factor Xa inhibitors (Pradaxa, Xarelto, Eliquis)—DOAC $$$

Non-Invasive Treatments:

• Rate control medications:

  • Calcium channel blockers: Diltiazem, etc.

  • Beta-blockers: Metoprolol, etc.

  • Digoxin

• Cardioversion: Often preceded by a transesophageal echocardiogram (TEE)

Invasive Procedures:

• Ablation/Maze Procedure: Small transmural incisions are made in the atria, resulting in scar formation.

• Left Atrial Appendage Occlusion (LAAO)/WATCHMAN: Reduces the risk of blood clots from entering the bloodstream and causing a stroke.

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• Acute + Symptomatic (unstable): Cardioversion → baseline

• Acute + Asymptomatic (stable): IV Amiodarone drip is first-line treatment:

  • Given an IV bolus dose of 150 mg over 10 minutes → Infusion/drip: 1 mg/min over 6 hours → 0.5 mg/min over 18 hours → transitioned to PO.

• Chronic: rate control (b/c they have already attempted to correct when first diagnosed, but efforts have failed)—BBs & CCBs

Left Atrial Appendage (LAA) Occlusion (WATCHMAN)

• 90% of clots are formed by a-fib that originate in the LAA.

• An endothelialized device is placed inside of that area and keeps/catches clots from getting out into the heart and the rest of the body.

Junction Arrhythmias

Originate within AV Nodal Tissue:

• Premature Junctional Complexes (PJCs)

• Junctional Rhythms

• Junctional Tachycardia

• Atrioventricular Nodal Reentry Tachycardia (AVNRT)

  • SVT (Supraventricular Tachycardia)

  • PVST (Paroxysmal Supraventricular Tachycardia)

  • PAT (Paroxysmal Atrial Tachycardia)

Junctional Rhythms: Criteria

• Rate: Atrial — 40 to 60 bpm (if there is retrograde conduction); Ventricular — 40 to 60 bpm

• Rhythm: Regular

• P Waves: May be absent, may be inverted

• P to QRS Ratio: 1:1 or 0:1

• PR Interval: If the P wave is in front of the QRS, the PR interval is less than 0.12 seconds

• QRS Complex: Usually normal

Junctional Rhythms: Causes, S/Sx, & Treatments

Causes:

• Hypokalemia and side effects of medications

• Myocardial infarction (MI)

• Cardiac surgery

• Digitalis (Digoxin) toxicity

• Sinus node dysfunction

• Post AV node ablation

Signs & Symptoms: (collapsed)

• Chest pain

• Oxygen deficiency

• Low blood pressure (BP)

• Lethargy

• Anxiety

• Palpitations

• Shortness of breath

• Elevated ventricular rate or heart rate

• Dizziness or syncope (fainting)

• Lightheadedness

• Activity intolerance

• Weakness

Treatments:

• Same as for sinus bradycardia — treat the underlying cause(s)!

• Lifestyle changes

• Medication changes

• Permanent pacemaker

Premature Junctional Complexes (PJCs)

Signs & Symptoms:

• Usually the same as PACs

  • The patient may say, “My heart skipped a beat.”

  • Possible pulse deficit (difference between the apical & radial pulse rates)

• Rarely produces significant symptoms

Causes:

• Digitalis (Digoxin) toxicity

• Heart failure

• Coronary artery disease

Treatment:

• Same for PACs — treat the underlying cause

• Change the medications and/or make lifestyle changes

• Permanent pacemaker

Junctional Tachycardia: Criteria

• Rate: Atrial — 70 to 120 bpm (if P waves are discernible); Ventricular — 70 to 120 bpm

• Rhythm: Regular

• P Waves: May be absent, after the QRS, or before the QRS; may be inverted

• P to QRS Ratio: 1:1 or 0:1

• PR Interval: If the P wave is in front of the QRS, the PR interval is less than 0.12 seconds

• QRS Complex: Usually normal, may be widened

Junctional Tachycardia: Causes, S/Sx, & Tachycardia

Causes:

• Digoxin toxicity is the cause of 60% of cases

• Inferior myocardial infarction

• Hypokalemia

• Open-heart surgery

Signs & Symptoms:

• Will depend on the precipitating cause

Treatment:

• Eliminate or treat the underlying cause (e.g., Digoxin toxicity)

• Antiarrhythmic drugs

• Permanent pacemaker

Atrioventricular Nodal Reentry Tachycardia (AVNRT)

• AVNRT is a common arrhythmia that occurs when an impulse is conducted to an area in the AV node, causing the impulse to be routed back into the same area repeatedly at a very fast rate.

• Each time the impulse is conducted through the area, it is also conducted down into the ventricles, resulting in a fast ventricular rate.

Supraventricular Tachycardia (PSVT or SVT): Criteria

• Rate: 150 to 250 bpm

• Rhythm: Regular, with sudden onset and termination

• P Waves: Difficult to discern

• P to QRS Ratio: 1:1

• PR Interval: If the P wave is visible, the PR interval is less than 0.12 seconds

• QRS Complex: Usually normal, may be slightly widened

PSVT: coming and going

SVT: typically sustainable, constant

Supraventricular Tachycardia (PSVT or SVT): Causes, S/Sx, & Diagnostics

Causes:

• Caffeine

• Nicotine

• Hypoxemia

• Stress

• Not associated with underlying structural heart disease

Signs & Symptoms (due to decreased cardiac output):

• Dizziness/Syncope

• Palpitations

• Restlessness

• Chest pain

• Shortness of breath

• Pallor

• Hypotension

Diagnostics:

• Clinical picture / History & Physical (H&P)

• ECG (basic and 12-lead)

• Blood work

• Echocardiogram

SVT: Treatments

Stable:

1. Vagal maneuvers (the first thing you want to do is get the pt. to bear down, cough, suction)

2. Adenosine: 6 mg → 12 mg → 12 mg IV, rapid push

   • Done in a controlled environment (ACLS nurse + provider @ bedside w/ crash cart and respiratory team)

   • Done in a sequence of doses until the pt’s HR goes down. (not all doses are necessarily used)

3. Consider synchronized cardioversion

4. IV calcium channel blocker or IV beta-blocker

Unstable:

• Immediate synchronized cardioversion

Long-Term:

• Ablation therapy

Treatment:

• Correct the underlying causes

• Administer fluids, blood products, and pain medications

• Reduce anxiety

• Discontinue medications or stimulants causing the issue

Defibrillation vs. Cardioversion

Defibrillation:

• Emergency procedure—used only for cardiac arrest.

• Not synchronized with the cardiac cycle

• Used for Ventricular Fibrillation (V-Fib) or pulseless Ventricular Tachycardia (V-Tach)

• No cardiac output

• Begin with 200 Joules, may increase up to 360 Joules

• Client is unconscious—Not used for patients who are conscious or have a pulse.

• Continuous ECG monitoring

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Cardioversion:

• Elective procedure

• For tachydysrhythmias (unstable)

• Client is awake and often sedated

• Synchronized with the QRS complex

• Energy level: 50 to 200 Joules

• Consent form required

• Continuous ECG monitoring

• **Switch to cardioversion sync mode!!*

Oh, Say It Isn’t So!—Preparing for Cardioversion

O – Oxygen monitoring
S – Suction equipment
I – IV access
I – Intubation supplies
S – Sedation and analgesics

Synchronized Cardioversion at Work

• Shock delivered on the R wave at ventricular depolarization.

Ventricular Dysrhythmias

Originate from Irritable Foci within the Ventricles:

• Premature Ventricular Complexes (PVCs)

• Ventricular Tachycardia (V-Tach)

• Polymorphic Ventricular Tachycardia (Torsades de Pointes)

• Ventricular Fibrillation (V-Fib)

• Ventricular Asystole

• Pulseless Electrical Activity (PEA)

Premature Ventricular Complexes (PVCs)

Causes:

• Cardiac ischemia or infarction, tissue hypoxia

• Anxiety, stress

• Caffeine, nicotine, alcohol

• Increased cardiac workload

• Electrolyte imbalances

Signs & Symptoms:

• “My heart skipped a beat”

• Often patients are asymptomatic (at first)

Treatments:

• Correct the cause

• Medications (antidysrhythmics)

• Lifestyle changes

• Ablation

Characteristics and Subtypes of PVCs

• Uniform

• Multiform

• Bigeminy (1, 2; 1, 2; 1, 2)

• Trigeminy (1, 2, 3; 1, 2, 3)

• Quadrigeminy (1, 2, 3, 4; 1, 2, 3, 4)

• Couplets

• Triplets

Ventricular Tachycardia (V-Tach): Criteria

• Rate: Atrial: Depends on the underlying rhythm; Ventricular: 100 to 200 bpm

• Rhythm: Usually regular

• P Waves: N/A

• P to QRS Ratio: N/A

• PR Interval: N/A

• QRS Complex: Greater than 0.12 seconds; wild, bizarre, and abnormal

**all are uniform

V-Tach: S/Sx & Causes

Signs & Symptoms:

• May or may not have a pulse —SO ASSESS FOR A PULSE FIRST! #1

• Hypotension

• Dizziness/lightheadedness

Causes:

• Ischemic heart disease/coronary artery disease (#1 cause)

• Hypoxemia

• Acid-base imbalance

• Cardiomyopathy

• Electrolyte imbalances

• Valvular disease

• Genetic abnormalities

• QT prolongation

V-Tach: Treatments

Stable:

• Patient is alert with a pulse.

• Obtain a 12-lead ECG

• Determine if sustained (> 3 seconds) or non-sustained.

• Try a vagal maneuver—to try and kick them back into a normal rhythm.

• If unresponsive to amiodarone, alternative drugs include procainamide, metoprolol, or sotalol.

  • First-line for wide complex V-tach:

    • Amiodarone 150 mg IV over 10 minutes.

    • Then 1 mg/min for the first 6 hours.

    • Followed by 0.5 mg/min for the next 18 hours.

• Consider Life Vest, AICD (automatic internal cardiac-defibrillator), or synchronized cardioversion (shock).

• **Adenosine may be considered only if the rhythm is regular and monomorphic**

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Unstable:

• Patient has lost consciousness and has no pulse.

• Call a code and begin CPR.

• Use an AED/defibrillator to deliver a shock immediately when available.

  • VT is a shockable rhythm and may not resolve spontaneously.

**If that AED/Defibrillator is readily available, the first choice is shock. If not, then CPR until you can get it**

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***Follow ACLS (Advanced Cardiovascular Life Support) guidelines for medication administration during a code.

Polymorphic V-Tach or Torsades de Pointes: Criteria

• Rate: Ventricular — 100 to 200 bpm

• Rhythm: Looks like twisting points or peaks on the ECG

• P Waves: N/A

• P to QRS Ratio: N/A

• PR Interval: N/A

• QRS Complex: Bizarre, with fluctuations in amplitude

“Twisting of Pointes”

Torsades de Pointes: Causes & Common Treatments

Causes:

• Similar to V-Tach and V-Fib

• Usually associated with low magnesium levels**

• Prolonged QT intervals (e.g., from amiodarone/procainamide)**

Common Treatments:

• Correct the underlying issue(s)

• IV magnesium sulfate 1 to 2 grams (first-line treatment)

• Isoproterenol, Mexiletine

• Atrial pacing (helps shorten QT interval)

• Antiarrhythmics can be considered, but they are often ineffective or harmful

• If stable: Implantable cardioverter defibrillator (ICD)

• Prepare for cardioversion

• If pulseless: CPR and defibrillation

Long QT Syndrome (LQTS)

Normal QT Interval:

• 0.35 to 0.45 seconds

Genetic/Inherited Causes:

• QT > 0.50 seconds

• A common cause of cardiac arrest among young people

• Often underdiagnosed

• Genetic testing is available

Acquired Causes:

• Drug-induced: Over 75 drugs can prolong the QT interval

Possible Contributors to Prolonged QT:

• Electrolyte imbalance

• Hypothermia

• Structural heart disease

• Female gender

• Abnormal thyroid function

Signs & Symptoms:

• Syncope

• Seizures

• Sudden death

Treatment:

• Eliminate medications that may contribute

• Potassium supplements

• Implantable Cardiac Defibrillator (ICD)

• Mexiletine (oral analog to Lidocaine)

• Beta-blockers (Shorten the QT interval)

Ventricular Fibrillation (V-Fib): Criteria, Causes, & Symptoms

Criteria:

• Rate: Chaotic

• Rhythm: Chaotic

• P Waves: Absent

• P to QRS Ratio: Absent

• PR Interval: Absent

• QRS Complex: Absent

• PULSELESS — ALWAYS

Causes:

• Coronary Artery Disease (CAD) → Myocardial Infarction (MI)

• Untreated or unsuccessfully treated V-Tach

• Cardiomyopathy

• Valvular heart disease

• Acid-base and electrolyte abnormalities

• Electrical shock

Symptoms:

• Always pulseless!

V-Fib: Treatments

Immediate Interventions:

• No pulse / No respirations → Call a CODE!!!

• Early and immediate defibrillation

• Do not delay defibrillation

• Perform high-quality CPR (30:2)

Medical/Pharmacological Management: ACLS meds

• Epinephrine 1 mg IV push every 3 to 5 minutes

• Amiodarone 300 mg initial IV bolus, followed by 150 mg (may substitute Lidocaine)

Post-Resuscitation Management:

• Amiodarone or Lidocaine drip (follow-up)

• Identify and treat reversible/underlying causes

Asystole: Criteria

• Rate: No pulse

• Rhythm: No rhythm (flatline)

• P Waves: Absent

• PR Interval: Not applicable

• QRS Complex: Absent

• Key Feature: NO PULSE! – Cardiac Arrest

**non-shockable rhythm

Pulseless Electrical Activity (PEA): Criteria

• Rate: Varies

• Rhythm: Varies

• P Waves: Varies

• P to QRS Ratio: Varies

• PR Interval: Varies

• QRS Complex: Varies

• Key Feature: Electrical activity present, but no pulse!

**Looks like sinus rhythm on the monitor, but the patient has no pulse.

**Usually seen after coding a pt. for a while. (post-code)

Medical Management of Pulseless Cardiac Arrest: Mind Your H’s and T’s

H’s:

• Hypovolemia

• Hypoxia

• Hydrogen ion (acidosis)

• Hypo/Hyperkalemia

• Hypothermia

T’s:

• Tension pneumothorax

• Tamponade, cardiac

• Thrombosis (coronary)

• Thrombosis (pulmonary)

**Treating the underlying causes

Conduction Defects

• Left and Right Bundle Branch Blocks

• First-Degree AV Block

• Second-Degree AV Block, Mobitz Type 1 (Wenckebach)

• Second-Degree AV Block, Mobitz Type 2

• Third-Degree (Complete)

Bundle Branch Blocks

• What is Happening:

  • First division of the ventricular conduction after the bundle of His.

  • A delay or blockage of the electrical impulses, resulting in the heart pumping blood less efficiently.

• Cause:

  • LBBB—MI, HTN, myocarditis, cardiomyopathy

  • RBBB—PE, MI, congenital heart defects, pulmonary HTN, myocarditis

• Signs & Symptoms:

  • Usually asymptomatic

  • Dizziness, syncope

• Treatment:

  • Usually not needed if asymptomatic

• Mnemonic: WilliaM MorroW—You need a 12 lead ECG looking at lead V1 and V6!

  • LBBB: V1 = W; V6 = M—90% are this!

  • RBBB: V1 = M; V6 = W

**William has L and Morrow has R

Atrioventricular (AV) Blocks

• The SIGNAL is DELAYED or BLOCKED WHEN MOVING from the ARTIA to the VENTRICLES.

• Caused by:

  • Lev’s disease

  • Ischemic heart disease

  • Cardiomyopathy

  • Myocarditis

• Three types:

  • 1st degree

  • 2nd degree

  • 3rd degree

First Degree AV Block: Criteria

• Looks like NSR except with a prolonged PR interval: greater than 0.20 seconds.

• Constant PR interval for each beat.

• Usually asymptomatic and only needs monitoring.

• If symptomatic, treat with atropine.

Second Degree AV Block—Mobitz Type 1 (Wenckeback): Criteria + Treatment

• PR Interval: Steady lengthening (slowly gets further from the QRS complex until the QRS complex disappears).

• QRS Complex: Dropped or blocked.

• PP Interval: Regular.

• RR Interval: Irregular.

• QRS: Normal.

• Decreased cardiac output may occur.

Treatment: If symptomatic, treat with atropine.

Second Degree AV Block—Mobitz Type II: Criteria + Treatment

• PR Interval: Fixed.

• PP Interval: Fixed.

• Occasional P wave not followed by QRS.

• Essentially, the PR interval is constant, and then the QRS is dropped.

• Typically unstable and needs treatment.

Treatment: Atropine or pacing.

Third-Degree AV Block (Complete Heart Block): Criteria + Treatment

• Atria and ventricles beat independently of each other.

• P waves are not associated with QRS complexes.

Treatment:

• Atropine can be given but is usually ineffective.

• Transcutaneous, transvenous, or implanted permanent pacemaker.

ACS/MI: Prevalence

Per the CDC:

• Approximately 695,000 people died from cardiac disease in 2021 (1 in 5 deaths).

• Over 800,000 people had heart attacks (1 attack every 40 seconds).

• CAD cost in the U.S. is about $239.9 billion in healthcare costs, services, and lost wages.

• About 1 in 5 (20%) of all heart attacks are “silent.”

Risk Factors for CAD

• Smoking**

• Hypertension

• Diabetes

• Hyperlipidemia

• Obesity

• Inactivity

• Family history

In-patients are highly susceptible to cardiac events. Why do you think this is?

• High concentration of high-risk populations.

• Metabolic syndrome (hyperlipidemia, hypertension, diabetes, and obesity)

• Physical/emotional stress

• Increased bed rest/immobility

• Medication changes

ACS Cascade

Ischemia → Injury → Necrosis

Stable Angina

• Character of Pain: Exertional pain

• Pattern: Crescendo-Decrescendo

• Relievers: Responds to NTG

• Enzymes: Normal

• ECG: Often Normal

Unstable Angina

• Character of Pain: Rest pain

• Pattern: Crescendo

• Relievers: No NTG effect

• Enzymes: Normal

• ECG: Often ST depression

NSTEMI

• Character of Pain: Rest pain

• Pattern: Crescendo

• Relievers: No NTG effect

• Enzymes: Elevated

• ECG: No ST segment elevation

STEMI

• Character of Pain: Rest pain

• Pattern: Crescendo

• Relievers: No NTG effect

• Enzymes: Elevated

• ECG: ST segment elevation

30 minutes

How long does it take to progress from the onset of ischemia to irreversible cardiac tissue necrosis?

Typical MI Symptoms

• Chest pain (crushing, squeezing, pressure, heaviness)

• Pain that radiates to jaw, shoulders, or back.

• Shortness of breath

Atypical MI Symptoms (silent MIs)

• Dizziness/lightheadedness/syncope

• Nausea/vomiting

• Diaphoresis/pallor

• Sudden weakness/tiredness

women, elderly, diabetics

20% of MIs do NOT present with typical symptoms, particularly in _____, _______, and _________. Treat it like an MI until proven otherwise.

12-Lead ECG

• 10 leads actually means 12 views.

• The views look at the heart’s electrical activity from multiple angles.

• Changes must be noted in at least two contiguous leads (looking at the same part of the heart) to be considered clinically significant.

Which Leads Look Where? (picture)

Which leads look at the lateral wall of the heart?

Leads: I, AVL, V5, and V6

Which leads look at the inferior wall of the heart?

Leads: II, III, and AVF

Which leads look at the septum/anterior wall of the heart?

Leads: V1 and V2

Which leads look at the just the anterior wall of the heart?

Leads: V3 and V4

When looking for ST segment elevation, what are the three areas you look at?

• PR segment

• J point

• ST segment

one small square, ABOVE

If the J point falls at least ___ _____ ______ (1mm) _____ your line, then you have ST elevation. If not, then you don’t have ST elevation.

Anteroseptal MI

Lateral MI

Inferior MI

MI Mimics

• Example:

  • Left Bundle Branch Block (most common)

  • Left Ventricular Hypertrophy (LVH)

  • Early Repolarization

  • Right Bundle Branch Block

• Changes (ST elevation are usually in all the leads, which gives it away that it’s not an MI.

full thickness

A STEMI indicates ____ _________ (inside and out) damage of the heart muscle (tissue death).

partial thickness

A NSTEMI indicates _______ _________ damage of the heart muscle. Electrical impulses show through the healthy sliver of tissue.

Cardiac Enzyme: Troponin T

• More hospital systems have switched to using 5th generation Troponin T tests, which are more sensitive and report results in whole numbers.

• If labs are drawn early when a patient shows symptoms of an MI, troponin levels may still be normal because it can take time for the heart tissue to release enough troponin into the bloodstream.

• If symptoms just began, the troponin may not yet be detectable and labs may need to be repeated later.

“Normal” Range for Troponin T (5th Gen)

• Males: < 15 ng/L

• Females: < 10 ng/L

99th Percentile for Troponin T (5th Gen)

• Males: 22 ng/L

• Females: 14 ng/L

Critical Value for Troponin T (5th Gen)

> 53 ng/L

10 minutes

If a patient starts complaining of chest pain or other symptoms that could indicate a heart attack, you have __ _______ to obtain a 12-lead ECG!

Nursing Interventions: ACS/MI

Obtain 12-lead ECG within 10 minutes at most!:

• Leave machine attached.

Call Rapid Response Team (RRT):

• Get ECG to interventional cardiologist.

Assess your patient:

• Baseline vital signs

• Ensure patent IV

If STEMI is confirmed:

• Prepare for cath lab:

  • Place defibrillator pads on patient

  • Shave groin and wrist sites (femoral/radial)

  • Administer meds per physician orders

  • Prepare for transport

If STEMI is ruled out:

• Administer meds per physician order.

ACS/MI: MONA—Pharmacological Nursing Interventions

Morphine:

• Given for pain, but no mortality benefit.

Oxygen:

• Usually only if pt.’s SpO2 is < 90%.

Nitroglycerin:

• Still used in presence of persistent ischemia.

Aspirin:

• 23% mortality reduction.

ACS/MI: Other Phamracological Interventions

Drugs of Choice that Improves Mortality:

• Fibrinolytics—if symptoms are <12 hours and prompt PCI is unavailable.

• Anticoagulants—anti-platelet.

• P2Y12 Inhibitors—prevent further platelet aggregation, preventing clots from getting bigger.

• Glycol. IIb/IIa Inhibitors—ONLY if the patient is unable to receive a P2Y12 Inhibitor.

• Beta Blockers—lowers HR and reduces workload of heart; be cautious and obtain baseline vitals.

• RAAS Inhibitors—lowers systemic vascular resistance/BP.

• Statins—given after the fact, to lower cholesterol.

PCI: Stent with Balloon Angioplasty

A procedure that leaves a permanent wire mesh within a coronary artery to restore flow to cardiac tissue.

Coronary Artery Bypass Graft (CABG)

When a PCI isn’t possible, blood vessels from other parts of the body can serve as conduits for blood to perfuse the heart.

• They include the internal thoracic or mammary artery (ITA or IMA), saphenous vein (SV), and radial artery (RA).

Intra-Aortic Balloon Pump & Impella Pump

These are temporary, in-hospital measures until definitive treatment can be completed. (bridge treatments)

• Both of these interventions are in place for less than 30 days.

• It buys the patient time until a PCI or CABG can be performed.

Intra-Aortic: it inflates and blocks the aorta during diastole and then during systole when the heart contracts, it deflates to let the blood pass. (improves injection fraction)

Impella: “outdoor motor”—it is fed up into the ventricle and it anchors itself in there. It helps push the blood out with every beat.

Cardiac Rehabilitation

• Recovery can generally take anywhere from 4 to 12 weeks.

• Cardiac rehab teams usually consist of physicians, nurses, exercise physiologists, dietitians, and clinical psychologists.

• Patient gradually increased physical activity over a couple of weeks, starting with several shot walks per day and increasing in length.

• Services can include physical exams, exercise sessions, health classes, therapy groups, dietary consults, and even grocery store tours.

ACS/MI: Patient Education

Lifestyle Changes:

• Smoking Cessation

• Dietary changes (low fat/cholesterol)

• Attend cardiac rehab and follow up cardiology appointments

• When to call their physician or 9-1-1

Medication Compliance and Potential Side Effects:

• Asprin

• Antiplatelets

• Beta blockers

• RAAS Inhibitors (ACE Inhibitors, ARBs, etc.)

• Statins

• Nitroglycerin (SL spray or tablets)

  • Keep in a cool, dry, and dark place (sensitive to light).

  • Only good for 3 to 5 months → replace.

  • Sit down when taking it because it significantly drops BP.

  • Take one every 3 to 5 minutes with of max of 3 doses.