Ventricular Fibrillation – 8 Interesting Facts

Sharing is caring!

What is Ventricular Fibrillation

Ventricular fibrillation, also called V-fib, is a type of abnormal heart rhythm (arrhythmia) that affects the lower chambers of the heart (ventricles)

When V-fib happens, disorganized electrical signals in the heart cause the ventricles to quiver instead of pumping blood normally. As a result, oxygen does not reach the brain and other important organs, and the heart suddenly stops beating.

Ventricular fibrillation is a life-threatening emergency and must be treated right away.

Synopsis

  1. Ventricular fibrillation is a life-threatening arrhythmia (fatal if not reversed) characterized by high-frequency, irregular waves of varying amplitude that can be seen on any type of ECG device
  2. Any patient in ventricular fibrillation will be unconscious and unresponsive to stimuli
  3. Causes include:
    • Myocardial and/or cardiac conduction system abnormalities, due to any of the following:
      • Chronic cardiac disease
      • Myocardial infarction and ischemia
      • Congenital abnormalities in cardiac conduction system
    • Electrolyte disturbances, including hypokalemia, which is the most common electrolyte abnormality in clinical practice
    • Electrocution
  4. Ventricular fibrillation must be differentiated from pulseless electrical activity and asystole, which are not shockable rhythms and thus are treated with different protocol in advanced cardiac life support
  5. Resuscitation is urgent and follows advanced cardiac life support algorithm for ventricular fibrillation and pulseless ventricular tachycardia, which are shockable rhythms
    • Cardiopulmonary resuscitation, countershock, epinephrine, and amiodarone are given in repeating cycles
  6. Major determinants of survival after ventricular fibrillation are the degrees of brain injury and cardiovascular instability
  7. Therapeutic hypothermia is recommended for any patient who is unconscious after resuscitation and is the only intervention demonstrated to improve neurologic recovery
  8. Incidence of cardiovascular instability is reduced with revascularization (eg, percutaneous coronary intervention, coronary bypass surgery), leading to improved survival

What are the causes?

This condition happens when the electrical signals that tell the heart to beat become disorganized. It can be caused by:

  • Lack of blood flow to the heart.
  • Diseases of the heart muscle (cardiomyopathy).
  • A damaged heart muscle caused by a heart attack.
  • Severe body infection (sepsis).
  • Problems with the main artery that leads blood away from the heart to the rest of the body (aorta).
  • Medicines.
  • Electrical shock.
  • Electrolyte abnormalities.

What increases the risk?

You are more likely to develop this condition if:

  • You are 45–75 years of age.
  • You have high blood pressure (hypertension).
  • You have diabetes.
  • You smoke.
  • You are male.
  • You have heart failure or a disease of the heart muscle (cardiomyopathy).
  • You have had a heart attack.
  • You have heart defects that you were born with (congenital heart defects).
  • You have an infection that affects the heart.
  • You have coronary artery disease.
  • You have certain genetic traits.

What are the signs or symptoms?

The main symptom of this condition is a sudden stop of the heartbeat (cardiac arrest). When this happens, you faint and become unresponsive. You will not be breathing normally and you will have no pulse. To survive, you must receive urgent treatment.

Before cardiac arrest, you may experience:

  • Fainting.
  • A rapid heartbeat.
  • Dizziness or light-headedness.
  • Shortness of breath.
  • Chest pain.
  • Nausea or vomiting.

How is this diagnosed?

This condition is diagnosed based on:

  • Your symptoms and medical history.
  • A physical exam.
  • An electrocardiogram (ECG). This test is done to check for problems with electrical activity in the heart.
  • A coronary angiogram. During this test, a dye is injected into your bloodstream. The dye shows up on an X-ray and shows how blood flows through the arteries that lead to the heart.

How is this treated?

CPR (cardiopulmonary resuscitation) should be started immediately. As soon as an automatic external defibrillator (AED) is available, apply the AED and follow the instructions. This condition is a medical emergency that must be treated immediately. If the arrest happens in the hospital, staff will use a defibrillator to restart the heart.

After the heart is restarted, treatment focuses on recovery and preventing V-fib. It may include:

  • Medicines that return the heart to a normal rhythm (anti-arrhythmics).
  • Treating any underlying conditions that may cause V-fib.
  • Cooling the body (therapeutic hypothermia). This can help decrease the risk of brain injury.
  • Having an implantable cardioverter defibrillator (ICD) inserted in your chest. An ICD is a small device that monitors your heartbeat. When it senses an irregular heartbeat, it sends a shock to bring the heartbeat back to normal.

Follow these instructions at home:

Medicines

  • Take over-the-counter and prescription medicines as told by your health care provider.

Eating and drinking

  • Eat a healthy diet. This includes lean meats, whole grains, low-fat or fat-free dairy products, and plenty of fruits and vegetables.
  • Avoid eating foods that are high in saturated fat, trans fat, sugar, or salt (sodium).
  • Limit alcohol intake to no more than 1 drink per day for nonpregnant women and 2 drinks per day for men. One drink equals 12 oz of beer, 5 oz of wine, or 1½ oz of hard liquor.

Activity

  • Rest as told by your health care provider.
  • Exercise regularly. Ask your health care provider what exercises are safe for you. Aim for 150 minutes of moderate exercise or 75 minutes of vigorous exercise per week.

Lifestyle

  • Do not use any products that contain nicotine or tobacco, such as cigarettes and e-cigarettes. If you need help quitting, ask your health care provider.
  • Maintain a healthy weight. Ask your health care provider what weight would be healthy for you.
  • Manage stress. Try to do this with relaxation exercises, yoga, quiet time, or meditation.
  • Ask your health care provider when it is safe for you to drive.

If you have an ICD:

  • Avoid spending long periods of time with electronic devices that have strong magnetic fields, such as cell phones, microwaves, or metal detectors.
  • Tell all your health care providers, including dentists, that you have an ICD.
  • If you are flying, tell airport security that you have an ICD.
  • Consider wearing a medical ID bracelet or necklace stating that you have an ICD.
  • At all times, carry the card you were given that has information about your ICD.
  • Ask your health care provider what activities are safe for you.

General instructions

  • Keep all follow-up visits as told by your health care provider. This is important. These include visits with your heart specialist.

Contact a health care provider if:

  • You have had a shock (discharge)from your ICD.

Get help right away if:

  • You have chest pain.
  • You have shortness of breath.
  • You have a rapid heartbeat.
  • You faint.
  • You feel dizzy or light-headed.

These symptoms represent a serious problem that is an emergency. Do not wait to see if the symptoms will go away. Get medical help right away. Call your local emergency services. Do not drive yourself to the hospital.

Summary

  • Ventricular fibrillation, also called V-fib, is a type of abnormal heart rhythm (arrhythmia) that affects the lower chambers of the heart (ventricles).
  • When V-fib happens, disorganized electrical signals in the heart cause the ventricles to quiver instead of pumping blood normally.
  • Ventricular fibrillation is a life-threatening emergency and must be treated right away.
  • The main symptom of this condition is a sudden stop of the heartbeat (cardiac arrest).
  • After a heartbeat is restored, this condition may be treated with medicines or an implantable cardioverter defibrillator (ICD).

Detailed Information

Pitfalls

  • When wave morphology is very fine, ventricular fibrillation can be difficult to differentiate from asystole; multiple leads are necessary because appearance of ventricular fibrillation in any lead provides a diagnosis of ventricular fibrillation, a shockable rhythm

Terminology

Clinical Clarification

  • Ventricular fibrillation is a cardiac arrhythmia characterized by high-frequency, disorganized, unsynchronized contraction of ventricular myocytes, such that no appreciable cardiac output is achieved and death occurs if it is not corrected

Diagnosis

Clinical Presentation

History

  • Any of the following:
    • Syncope, with or without prodrome
      • Prodrome consists of nonspecific symptoms (eg, chest pain, arm pain, palpitations, fatigue)
    • Prior ventricular tachycardia, which deteriorated to ventricular fibrillation 2
    • Conversion from an initially nonshockable rhythm (ie, pulseless electrical activity, asystole) 3

Physical examination

  • Patient is unconscious and unresponsive to stimuli
  • No pulse and no blood pressure when chest compressions are not being applied
    • Resuscitation algorithms include cardiopulmonary resuscitation pauses to assess whether heart is effectively pumping blood
    • Exception is a patient with a nonpulsatile left ventricular assist device, who will not have a pulse or conventionally measurable blood pressure anyway
  • No heart sounds on auscultation
  • Cold skin and extremities in most cases

Causes and Risk Factors

Causes

  • Myocardial and/or cardiac conduction system abnormalities, due to any of the following:
    • Chronic cardiac disease
      • Coronary artery disease with high levels of vascular stenosis
      • Cardiomyopathy
    • Myocardial infarction and ischemia 4
    • Congenital abnormalities in cardiac conduction system 5
      • Can trigger ventricular fibrillation directly or can decrease threshold for developing ventricular fibrillation in setting of electrolyte disturbance
      • Includes Wolff-Parkinson-White syndrome, wherein patients with anomalous conduction have recurrent episodes of supraventricular tachycardia 6
    • Other congenital heart disease (eg, left ventricular outflow tract obstruction, corrected transposition of the great arteries, Ebstein anomaly, repaired tetralogy of Fallot) 7
    • Bradycardia (eg, in setting of myocardial ischemia and infarction) 4
    • Congenital long QT syndrome 4
      • Inherited condition characterized by prolonged QT interval, torsades de pointes, and sudden cardiac death
  • Electrolyte disturbances
    • Hypokalemia (less than 3.6 mEq/L) 8
      • Most common electrolyte abnormality in clinical practice 8
      • Present in:
        • 7% to 17% of patients with cardiovascular disease 9
        • Up to 20% of hospitalized patients 9
        • 10% to 40% of patients on thiazide diuretics 8
        • Almost 50% of patients resuscitated from out-of-hospital ventricular fibrillation 8
    • Hyperkalemia (more than 10 mEq/L) 8
    • Severe hypomagnesemia (less than 0.8 mEq/L) 8 10
    • Combined hyperkalemia and hypocalcemia 8
      • Hypocalcemia occurs frequently in chronic renal insufficiency, usually with other electrolyte abnormalities
  • Electrocution
    • Much less common than disease but includes:
      • Shock from electrical equipment 11
      • Lightning strikes 11
      • Strike from electroshock weapon (eg, Taser, stun gun) 12
        • Cardiac risk profile is generally low, but theoretical possibility of ventricular fibrillation is a concern in people with coronary artery disease or other cardiac pathology
  • Sympathetic stimulation 4
    • Left and right stellate ganglion stimulation induces ventricular fibrillation
  • Metabolic acidosis 4
  • Drugs
    • Antiarrhythmic drugs (eg, dofetilide, flecainide, sotalol)
    • Psychiatric drugs (eg, lithium, haloperidol, thioridazine, other phenothiazines)
    • Antibiotics (eg, fluoroquinolones; macrolides and prolongation of QT interval [mortality of 1 in 30,000; occurrence of serious arrhythmia, 1 in 8500]) 13
    • Digitalis or digoxin toxicity 4

Risk factors and/or associations

Age
  • Peak incidence in people aged 45 to 75 years 14
Sex
  • 3:1 incidence ratio in men versus women, largely owing to increased incidence of coronary artery disease 15
Genetics
  • Presence of rs2824292 variant on chromosome 21q21 locus has been associated with increased incidence of ventricular fibrillation in setting of acute myocardial infarction, 16 although the association may not hold for all patient groups 17
  • SCN5A gene variant (sodium voltage-gated channel alpha subunit 5; OMIM #600163) 19 is associated with Brugada syndrome, a rare, inherited abnormality of voltage-gated sodium channels manifesting in ventricular fibrillation and sudden death with an anatomically normal heart 18
  • SCN5A variants also are linked to various cardiomyopathies that can lead to ventricular fibrillation 20
  • As many as 17 different genes have been reported in association with long QT syndrome 21
Ethnicity/race
  • Postdischarge survival after in-hospital cardiac arrest has been reported to be significantly less likely in African American versus white American patients 22
    • Lower rates of survival are also reported for immediate resuscitation and postresuscitation periods
    • Racial association with survival appears to be related to hospital center in which patients receive care
Other risk factors/associations
  • History of left ventricular dysfunction, especially with ejection fraction less than 35% 23
  • Smoking, hypertension, and diabetes mellitus, owing to associations with coronary artery disease
  • Hypertrophic cardiomyopathy
    • Inherited condition in which the left ventricular wall thickens—not in response to increased load—and causes obstruction to left ventricular outflow and development of ventricular arrhythmias
  • Arrhythmogenic right ventricular dysplasia (arrhythmogenic right ventricular cardiomyopathy)
    • Rare, inherited condition in which nonischemic cardiomyopathy of the right ventricle develops (fibrous and fatty tissues replace normal myocardium) and ventricular arrhythmias occur
  • Brugada syndrome 18
    • Rare, inherited abnormality of voltage-gated sodium channels that leads to ventricular fibrillation and sudden death in a structurally normal heart

Diagnostic Procedures

  • From Goldberger AL: Ventricular arrhythmias. In: Goldberger AL, ed: Clinical Electrocardiography: A Simplified Approach. 7th ed. Philadelphia, PA: Mosby; 2006:189-202, Figure 16-13.Coarse and fine ventricular fibrillation. – Ventricular fibrillation may produce both coarse and fine waves. Perform immediate defibrillation.

Primary diagnostic tools

  • Confirm diagnosis of ventricular fibrillation via any of the following: 24
    • Standard 3-lead ECG monitoring
      • Electrodes are on left arm, right arm, and left leg, yielding leads I, II, and III of a standard ECG
    • Standard 12-lead ECG also can be used, with drawback that it takes longer to attach
    • Mobile cardiac monitoring with telemetry 25
      • Patient wears a device (several are available) that records ECG activity and transmits telemetry for instantaneous notification of patient’s physicians and emergency medical services
      • Devices vary in number of electrodes and leads (can have as few as 1 lead) and placement of electrodes, but all arrangements will detect ventricular fibrillation
  • Investigate for precipitating factors (eg, electrolyte abnormalities, myocardial infarction, structural heart disease) 1
    • May include CBC, electrolytes, serum toxicology, coronary angiography, echocardiography, and electrophysiological studies 26 27
    • Consider genetic testing to identify an inherited arrhythmia syndrome in patients who are younger than 40 years and who have no evidence of structural heart disease 1

Laboratory

  • Serum electrolytes 8
    • Check for low potassium level and low magnesium level
  • Cardiac enzymes 24
    • Trend troponin levels to diagnose acute myocardial infarction
    • Initial troponin level and especially creatine kinase level will be elevated immediately after resuscitation

Functional testing

  • ECG
    • Ventricular fibrillation features
      • Irregular waves, varying in amplitude, with rates up to 500 beats per minute
      • Absence of P, QRS, and T waves
      • Typically, evolves from coarse (greater amplitude) to fine
        • When very fine, can be difficult to differentiate from asystole
        • When very fine, look at multiple leads (at least 2); identification of ventricular fibrillation in any lead is diagnostic of the arrhythmia and amenable to countershock

Procedures

Coronary angiogram 28
General explanation
  • Catheters are placed percutaneously in peripheral blood vessels and advanced into central circulation
  • Measures:
    • Intravascular pressure
    • Oxygen saturation in heart and great vessels
    • Cardiac contractility and function
  • Angiography delineates anatomic structures and coronary artery patency
  • Usually performed under light sedation
Indication
  • Emergently indicated for patients with out-of-hospital cardiac arrest of suspected cardiac origin and with ST-segment elevation on ECG
  • Reasonably used for select patients who are comatose after out-of-hospital cardiac arrest of suspected cardiac origin and have no ST-segment elevation (eg, with electrical or hemodynamic instability)
Contraindications
  • Contrast medium allergy
  • Severe anemia
  • Uncontrolled coagulopathy
Complications
  • Uncommon
    • Bleeding/hematoma
    • Thromboembolism
    • Arrhythmia
    • Allergic reaction to contrast medium
    • Perforation of blood vessel

Differential Diagnosis

Most common

  • Pulseless electrical activity (also called ) 29electromechanical dissociation
    • Cardiac output is absent despite presence of organized cardiac electrical activity (except ventricular tachycardia)
      • Encompasses various arrhythmias with no detectable pulse
        • Pulseless ventricular tachycardia is an exception
          • Technically an organized rhythm but not categorized as pulseless electrical activity because it is treated the same way as ventricular fibrillation
    • Similarities with ventricular fibrillation
      • Absence of pulse and blood pressure
    • Differences from ventricular fibrillation
      • Organized electrical rhythm is visible
      • Nonshockable rhythm
    • Definitive diagnosis is based on presence of an organized rhythm that should produce a pulse but does not
  • Pulseless ventricular tachycardia
    • Abnormally rapid regular heartbeat (resting heart rate more than 100 beats per minute) arising in the ventricles, not producing a pulse
    • Similarities with ventricular fibrillation
      • Absence of pulse and blood pressure
      • Shockable rhythm
    • Differences from ventricular fibrillation
      • Monitor shows regular, rapid, organized ventricular rhythm
    • Definitive diagnosis is based on presence of regular, rapid, organized ventricular activity on ECG or cardiac monitor that does not produce a pulse
  • Asystole 30
    • Ventricular depolarization and cardiac output both are absent
    • Similarities with ventricular fibrillation
      • Absence of pulse and blood pressure
    • Differences from ventricular fibrillation
      • Monitor shows no electrical activity
        • Must be verified by observing at least 2 leads; otherwise, can be confused easily with very fine wave ventricular fibrillation
      • Nonshockable rhythm
    • Diagnosis is made on basis of 12-lead ECG or cardiac monitor findings
  • Ventricular tachycardia with a pulse 2
    • Abnormally rapid heartbeat (resting heart rate more than 100 beats per minute) arising in the ventricles
      • Distinguished from pulseless ventricular tachycardia because ventricular tachycardia without a pulse is managed with the same resuscitation algorithm as ventricular fibrillation
    • Similarities with ventricular fibrillation
      • Can present with syncope
    • Differences from ventricular fibrillation
      • Syncope often does not occur; patients may instead present with palpitations and/or lightheadedness, sometimes with chest pain
      • QRS complexes are present on cardiac monitoring
    • Diagnosis is made on basis of 12-lead ECG or cardiac monitor findings

Treatment

  • From Nolan JP et al: European Resuscitation Council guidelines for resuscitation 2005: Section 4. Adult advanced life support. Resuscitation. 67(suppl 1):S39-86, 2005.Adult advanced life support cardiac arrest algorithm. – ALS, advanced life support; CPR, cardiopulmonary resuscitation (30:2 is the compressions to breaths ratio); PEA, pulseless electrical activity; VF, ventricular fibrillation; VT, ventricular tachycardia.

Goals

  • Achieve cardiac resuscitation, with conversion to a stable rhythm and stable hemodynamics 29
  • Treat underlying cause to avoid further episodes 29
  • Prevent brain damage from ischemia and reperfusion injury 31

Disposition

Admission criteria

After resuscitation, admit all patients who are not already hospitalized

Criteria for ICU admission
  • After resuscitation, admit all patients to ICU

Recommendations for specialist referral

  • Refer all patients to cardiologist
    • For patients whose ventricular fibrillation resulted from ectopic foci or other structural heart abnormalities: refer to subspecialist in interventional electrophysiology to be assessed for potentially beneficial procedures, such as ablation
    • For patients with ventricular fibrillation resulting from ST-elevation myocardial infarction: refer to interventional cardiologist for urgent angiography and revascularization 1

Treatment Options

Cardiac resuscitation 24

  • Follows advanced cardiac life support algorithm for ventricular fibrillation or pulseless ventricular tachycardia
  • In-hospital, this begins with the first rescuer calling the appropriate code for cardiac arrest (generally code blue in the United States and Canada) and beginning cardiopulmonary resuscitation as the resuscitation team makes its way and implements the algorithm
    • Begin cardiopulmonary resuscitation and provide 100% oxygen if possible (ie, with bag-valve mask or when intubated) 23
      • Perform cardiopulmonary resuscitation with compression-ventilation ratio of 30:2 and continue until advanced airway is inserted (for both adults 29 and children 34); a rate of 10 breaths per minute (1 breath every 6 seconds) may also be reasonable 32 33
      • Once an advanced airway has been inserted, perform continuous compressions with positive pressure ventilation delivered at the rate of 1 breath every 6 seconds (10 breaths per minute) without pausing chest compressions 35
    • Attach monitor/defibrillator 23
      • Device delivers direct current countershock if indicated by rhythm
      • Manual mode is appropriate for very well-trained personnel because chest compressions can be continued during charging
      • Semiautomatic mode is easier to use, delivers fewer inappropriate shocks, and is recommended
      • Automatic external defibrillator is increasingly being used in nonhospital settings
        • Availability of automatic external defibrillators is strongly recommended in public places, including airline terminals and flights; in the field, automatic external defibrillators are to be used within 5 minutes of cardiac arrest or as soon as cardiac arrest is recognized 36
        • Advantage: computer diagnoses arrhythmia, decides whether it is shockable, and chooses charge, allowing automatic external defibrillator to be used by rescuers whose capability is limited to basic life support; defibrillation can begin before more highly trained rescue team arrives
        • Disadvantage: long delays (up to 1 minute) between stopping chest compressions and delivering shock
          • With many automatic external defibrillators, an experienced operator can bypass the automated rhythm, thus decreasing waiting time until shock
      • Assess rhythm on cardiac monitor
      • Finding of ventricular fibrillation warrants proceeding to algorithm for shockable rhythms (ventricular fibrillation or pulseless ventricular tachycardia)
      • Before countershock, secure oxygen supply (ie, turn off or turn away from patient) and verify that nobody is in contact with patient 37
      • Give countershock (360 J in adults; 2-4 J/kg in children 34), then resume cardiopulmonary resuscitation 37
      • If airway is obstructed, pause compressions, insert airway device, then resume compressions
        • If advanced airway is secured, adjust ventilation to 1 breath each 6 seconds, yielding 10 breaths per minute, with air delivery of 1 second per breath (until visible chest rise); asynchronous with chest compressions
      • Consider capnography to confirm adequate ventilation
      • Obtain IV access; if this cannot be achieved rapidly (30-60 seconds), obtain intraosseous access
      • Remaining steps are repeated in a cycle until return of spontaneous circulation
        • Give countershock (360 J in adults; 2-4 J/kg in children 34)
        • Give epinephrine during cardiopulmonary resuscitation cycle (when spontaneous circulation has not yet returned after countershock)
          • Give IV or intraosseous bolus and continue dose every 3 to 5 minutes
          • No limit on number of doses
        • Assess rhythm
        • If shockable rhythm is still present, shock again (360 J in adults; 2-4 J/kg in children 34)
        • Give amiodarone (preferred) or lidocaine during cardiopulmonary resuscitation cycle (when spontaneous circulation has not yet returned after countershock and epinephrine)
        • Correct reversible causes, such as electrolyte imbalances
        • Resume cardiopulmonary resuscitation
        • Assess rhythm

Postresuscitation

  • Supportive treatment
    • If not already established, obtain IV access
    • Consider fluid bolus in patients who are hypotensive, maintaining systolic blood pressure of 90 mm Hg or more or mean arterial pressure of 65 mm Hg or more, using dopamine, norepinephrine, or epinephrine
    • Obtain 12-lead ECG and treat patients with high suspicion of acute myocardial infarction according to local protocols, using medical or interventional therapy as needed
    • Additional measures may include coronary reperfusion, ventilatory support, temperature control, and identification and treatment of any reversible causes such as electrolyte imbalance or structural heart disease 38
  • Therapeutic hypothermia
    • Only intervention demonstrated to improve neurologic recovery 28
    • Recommended immediately for any patient who is unconscious after resuscitation, especially if patient is comatose or if ventricular fibrillation began out-of-hospital (eg, unwitnessed/unobserved) 31
      • Also may be beneficial after resuscitation from ventricular fibrillation that developed in-hospital
    • Optimal timing for start of hypothermia and optimal duration remain to be determined, but begin hypothermia as soon as possible after resuscitation 31
  • Subsequent management and secondary prevention
    • Initiate or optimize medical therapy for associated conditions (eg, ischemic heart disease, heart failure, cardiomyopathies)
    • Start anti-arrhythmic drug therapy using β-blockers and/or class III anti-arrhythmic drugs if indicated, depending on underlying cause; may reduce recurrent ventricular fibrillation episodes 38
    • Implantation of a left ventricular assist device or extracorporeal life support may be required for unstable patients with recurrent episodes of ventricular fibrillation despite medical therapy 1
    • Catheter ablation of electrophysiologic pathways may be an option for patients with recurrent arrhythmias in whom antiarrhythmic medication is ineffective 1 39
    • Implantation of an implantable cardioverter defibrillator is strongly recommended for secondary prevention of ventricular fibrillation unless it was due to a correctable cause (eg, myocardial infarction, electrolyte imbalance, medications) or patient is unlikely to survive for more than 1 year 1 40

Drug therapy

  • Epinephrine 29
    • Use for ventricular fibrillation/paroxysmal ventricular tachycardia that does not respond to cardiopulmonary resuscitation and defibrillation
    • IV or intraosseous administration
      • Epinephrine Hydrochloride Solution for injection; Neonates†: 0.01 to 0.03 mg/kg/dose (0.1 to 0.3 mL/kg/dose of a 0.1 mg/mL solution) IV; may repeat every 3 to 5 minutes. After administration, flush the IV line with 0.5 to 1 mL of 0.9% Sodium Chloride Injection to ensure drug delivery.
      • Epinephrine Hydrochloride Solution for injection; Infants†, Children†, and Adolescents†: 0.01 mg/kg/dose (0.1 mL/kg/dose of a 0.1 mg/mL solution) IV or IO; may repeat every 3 to 5 minutes. Max: 1 mg/dose (10 mL/dose of a 0.1 mg/mL solution).
      • Epinephrine Hydrochloride Solution for injection; Adults: 1 mg (10 mL of a 0.1 mg/mL solution) IV or IO; may repeat every 3 to 5 minutes.
    • Endotracheal administration (if IV or intraosseous administration cannot be established)
      • Epinephrine Hydrochloride Solution for injection; Neonates†: 0.05 to 0.1 mg/kg/dose (0.5 to 1 mL/kg/dose of a 0.1 mg/mL solution) ET; may repeat every 3 to 5 minutes until IV or IO access obtained. After administration, flush with 0.5 to 1 mL of 0.9% Sodium Chloride Injection and deliver several consecutive ventilations.
      • Epinephrine Hydrochloride Solution for injection; Infants†, Children†, and Adolescents†: 0.1 mg/kg/dose (0.1 mL/kg/dose of a 1 mg/mL solution) ET; may repeat every 3 to 5 minutes until IV or IO access obtained. Max: 2.5 mg/dose (2.5 mL/dose of a 1 mg/mL solution). After administration, flush with 5 mL or more of 0.9% Sodium Chloride Injection and deliver 5 consecutive ventilations.
      • Epinephrine Hydrochloride Solution for injection; Adults: 2 to 2.5 mg ET; may repeat every 3 to 5 minutes until IV or IO access obtained. Dilute dose in 5 to 10 mL Sterile Water for Injection or 0.9% Sodium Chloride Injection.
  • Amiodarone 29
    • Consider for ventricular fibrillation/paroxysmal ventricular tachycardia that does not respond to cardiopulmonary resuscitation, defibrillation, and epinephrine
      • Amiodarone Hydrochloride Solution for injection; Neonates, Infants, Children, and Adolescents: 5 mg/kg IV given IV push for VF or pulseless VT; may repeat twice up to 15 mg/kg IV (Max single dose: 300 mg IV). May use intraosseous route if IV access not available.
      • Amiodarone Hydrochloride Solution for injection; Adults: 300 mg IV, which may be followed by 150 mg IV. May use intraosseous route if IV access not available. Clinical guidelines suggest amiodarone for patients who are unresponsive to CPR, defibrillation, and vasopressor; CPR should not be interrupted to administer drug therapy.
  • Lidocaine 29
    • Alternative to amiodarone; consider for ventricular fibrillation/paroxysmal ventricular tachycardia that does not respond to cardiopulmonary resuscitation, defibrillation, and epinephrine
      • Lidocaine Hydrochloride Solution for injection; Children: 1 mg/kg IV (Max: 100 mg IV); may repeat every 5 to 10 minutes up to 3 mg/kg IV.
      • Lidocaine Hydrochloride Solution for injection; Adults: Initially, 50 to 100 mg IV; may repeat in 5 minutes (Max: 300 mg IV over 1 hour). Alternatively, 0.5 to 0.75 mg/kg IV up to 1 to 1.5 mg/kg IV; may repeat 0.5 to 0.75 mg/kg IV every 5 to 10 minutes. Max: 3 mg/kg. See CPR indication for cardiac arrest dosage.

Nondrug and supportive care

Procedures
Therapeutic hypothermia 28

General explanation

  • Patient who regains spontaneous circulation and is unconscious after resuscitation from ventricular fibrillation is cooled actively to 32°C to 34°C for cerebral protection
    • Patient is kept hypothermic generally for 24 hours, although optimal time has yet to be determined
    • Shivering is prevented pharmacologically (eg, propofol or midazolam as sedative plus fentanyl or hydromorphone as analgesic)
  • Cooling techniques include:
    • Surface cooling devices and feedback-controlled endovascular catheters
    • Cooling blankets and frequent ice bag application
    • Initial cooling with iced isotonic saline, combined with other cooling methods to maintain cooling
      • Use IV ice-cold fluids (500 mL to 30 mL/kg 0.9% saline or lactated Ringer solution)
  • Rewarming
    • Start rewarming 12 to 24 hours after cooling begins
    • Rewarm slowly at 0.25°C every hour until 37°C is reached, taking approximately 12 to 16 hours to rewarm
    • Avoid hyperthermia (using cooling blankets if needed)

Indication

  • Unconscious patient after return of spontaneous circulation
    • Indication is particularly strong if patient is comatose and/or ventricular fibrillation began out-of-hospital
  • For cerebral protection to increase chances of survival after resuscitation
  • Consider for any patient who is unable to follow verbal commands after return of spontaneous circulation

Contraindications

  • Patient has not lost consciousness or perfusion was restored via cardiopulmonary resuscitation immediately after cardiac arrest

Complications

  • Shivering
  • Bradycardia with hypotension
  • Hyperglycemia
  • Hypokalemia
  • Immunosuppression

Monitoring

  • In survivors of cardiac arrest, monitor vital signs closely and observe with continuous ECG monitoring throughout transport and care, until stable 28
    • Obtain 12-lead ECG as soon as possible and evaluate for evidence of myocardial infarction
  • During induced hypothermia, monitor the following: 28
    • Maintain SaO₂ of 94% to 96%, 41 reducing FIO₂ to avoid prolonged exposure to 100% oxygen
    • Measure blood glucose level at least hourly to detect hyperglycemia; treat when glucose level exceeds 200 mg/dL
    • Measure serum potassium level at least every 4 to 6 hours to detect hypokalemia; correct as needed to maintain potassium level above 3.5 mEq/L

Complications and Prognosis

Complications

  • Myocardial ischemia
    • Permanent myocardial damage may be prevented via revascularization (eg, percutaneous coronary intervention, coronary bypass surgery), greatly improving survival 28
  • Cerebral ischemia/anoxia
    • Manifestations include cognitive deficits, seizures, coma, and death
    • May be prevented with therapeutic hypothermia
  • Cardiogenic shock
  • Acute renal failure
  • Hepatic failure
  • Respiratory failure
  • Hyperglycemia
  • Adrenal insufficiency
  • Pulmonary embolism

Prognosis

  • Major determinants of survival after ventricular fibrillation 28
    • Brain injury
      • May be prevented with therapeutic hypothermia, leading to improved survival
    • Cardiovascular instability
      • Incidence is reduced with revascularization (eg, percutaneous coronary intervention, coronary bypass surgery), leading to improved survival
        • Percutaneous coronary intervention may be performed concurrently with hypothermia 28
  • Chances of survival are influenced by multiple factors connected with how quickly treatment is started after cardiac arrest 28
    • Factors in out-of-hospital setting:
      • Bystander cardiopulmonary resuscitation
      • Speed of arrival of emergency medical services, defibrillation, and advanced life support
      • Transport to hospital
      • Availability of automatic external defibrillators in communities and abundance of people trained to use them
    • Survival has been calculated to decline at a rate of 7% to 10% per minute of delay between collapse and defibrillation when no cardiopulmonary resuscitation is provided 37
      • When bystander cardiopulmonary resuscitation is provided, the decline in survival is more gradual, averaging 3% to 4% per minute from collapse to defibrillation
    • Reported overall survival rates vary widely from 1.4% (lower survival rate with unwitnessed arrest) 42 to 39% (higher survival rates when emergency medical service personnel were present at time of arrest) 43

Screening and Prevention

Screening

At-risk populations

  • Offer screening to all people with family history of sudden death in first-degree relatives; risk is especially high if relatives died young 44

Screening tests

  • Use 12-lead ECG and echocardiogram to determine presence of structural heart disease and cardiac conduction defects (eg, prolonged QT interval, preexcitation)
  • Genetic testing for inherited arrhythmia syndromes and cardiomyopathies may also be indicated 1

Prevention

  • Achieve early diagnosis and treatment of coronary artery disease and mitigation of risk factors (eg, smoking, diabetes) 4
  • Recognize anatomic factors that increase the risk of arrhythmia (eg, Wolff-Parkinson-White syndrome) and treat appropriately (eg, ablation) 6
  • Recognize hypokalemia and other electrolyte abnormalities that contribute to arrhythmia development and treat appropriately 9
  • Consider implantable cardioverter defibrillator for selected patients (eg, inherited arrhythmia syndromes, hypertrophic cardiomyopathy, certain subgroups of those with ischemic heart disease) 1

Sources

1 Al-Khatib SM et al: 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 138(13):e210-71, 2018 Reference

Sharing is caring!

Diphenhydramine

Diphenhydramine Brand Names Aid to Sleep | Alka-Seltzer Plus Allergy | Aller-G-Time...

Dinutuximab

Dinutuximab Brand Name– Unituxin What is Dinutuximab Dinutuximab is a...

You cannot copy content of this page

shares
15585

Sign up to receive the trending updates and tons of Health Tips

Join SeekhealthZ and never miss the latest health information

15856
Scroll to Top