chapter 34: Care of Patients with Dysrhythmias
1. A patient is admitted to a telemetry unit with a new diagnosis of atrial fibrillation (AF). The patient states, "I feel fine, this rhythm won't hurt me." Which nursing response is appropriate? A. "AF can cause clots to form from the irregular blood flow in the heart." B. "It's important to monitor the AF for 24 hours." C. "AF leads the death of the heart muscle." D. "AF can cause cardiac output to increase."
A Many times, patients are found to have atrial fibrillation and they may be asymptomatic. While some patients do live with long-term atrial fibrillation, they need to be anticoagulated to decrease the risk of embolus formation due to the irregular cardiac rhythm. AF does not cause death of the heart muscle, nor does it cause the cardiac output to increase. Cardiac output will decrease due to the shortened filling time in the atria, which contributes to the development of heart failure due to altered conduction. While monitoring the patient is appropriate, it is not the best response to help educate the patient on the process of atrial fibrillation.
1. The nurse working in the outpatient setting identifies which dysrhythmia as the most commonly diagnosed? A. Atrial fibrillation B. Sinus tachycardia C. Sinus bradycardia D. Ventricular fibrillation
A - Rationale: Atrial fibrillation (AF) is the most common dysrhythmia seen in clinical practice. It is responsible for a third of hospitalizations for cardiac rhythm disturbances. Patients can live with this dysrhythmia, but most are treated with anticoagulation therapy to avoid possible blood clots.
what is automated external defibrillation (AED)
AEDs create an opportunity for laypersons to respond to cardiac arrest AEDs analyze the rhythm and shocks are delivered for ventricular fibrillation or pulseless ventricular tachycardia only
what is the etiology and risk of afib
AF is associated with atrial fibrosis and loss of muscle mass. These structural changes are common in heart diseases such as hypertension, heart failure, and coronary artery disease. For those without an underlying disorder leading to the development of AF, as many as 30 genetic mutations have been identified as the potential cause (Palatinus & Das, 2015). Investigation continues in the development of genetic testing to identify patients at risk and targeted treatment (Palatinus & Das, 2015). As AF progresses, cardiac output decreases by as much as 20% to 30%.
what is vfib
Also called V fib—result of electrical chaos in ventricles · Rather than a tachy-dysrhythmia, Ventricular fibrillation (V-fib) is really no rhythm at all. Essentially, the ventricular myocardial cells are firing chaotically with no resulting contraction. Imagine ventricles made of quivering jello, and about as effective. In cases of pulseless v-tach and v-fib, I am confident you can intervene effectively; because you have all provided evidence of your competence in Basic Cardiac Life Support. Once you assess to establish pulselessness, call a code blue and send for a crash cart/ defibrillator as you initiate high quality CPR. Please, note the critical rescue box on page 686 related to defibrillation safety. Although early defibrillation is key to restoring cardiac function, we must keep that blood oxygenated and circulating. Without intervention, course V-fib, depicted here, will progress to fine V-fib, and then asystole (or the absence of ventricular depolarization).
what is ventricular tachycardia
Also called V tach—repetitive firing of irritable ventricular ectopic focus, usually at 140 to 180 beats/min · you will note, has a wide QRS and no p-waves, because the impulse causing ventricular depolarization is being generated by the ventricular cells. An inherent ventricular rate is about 40 bpm. V-tach is usually 140-180bpm. If you count the QRS in this 6 second strip, the rate calculates at nearly 170/min, hence ventricular tachycardia demonstrates highly irritable myocardial cells. The key to determining appropriate nursing action is in client assessment. Although ventricular rhythms can maintain hemodynamic stability, the heart cannot sustain this rhythm indefinitely. If the client has a pulse, the provider should be notified immediately and synchronized cardioversion should be anticipated. However, v-tach in pulseless clients is treated the same as ventricular fibrillation. If not addressed, V-tach will progress to Ventricular fibrillation. · sometimes referred to as V tach, occurs with repetitive firing of an irritable ventricular ectopic focus, usually at a rate of 140 to 180 beats/min or more (Fig. 34-13). VT may result from increased automaticity or a re-entry mechanism. It may be intermittent (nonsustained VT) or sustained, lasting longer than 15 to 30 seconds. The sinus node may continue to discharge independently, depolarizing the atria but not the ventricles, although P waves are seldom seen in sustained VT.
what is ventricular asystole
Also called ventricular standstill—complete absence of any ventricular rhythm. There are no electrical impulses in the ventricles and therefore no ventricular depolarization, no QRS complex, no contraction, no cardiac output, and no PERFUSION to the rest of the body Ø high quality CPR according to your American Heart BLS training is the most appropriate intervention for this rhythm or any pulseless state.
what is the medication therapy for atrial dysrhythmias
Antidysrhythmics Anticoagulants
what is defibrillation
Asynchronous countershock that depolarizes critical mass of myocardium simultaneously to stop re-entry circuit and allow sinus node to regain control of heart
what are the specialized myocardial cells
Automaticity Excitability Conductivity Contractility
what is the management of cardiac arrest
CPR -Maintain patent airway -Ventilate with mouth-to-mask device -Start chest compressions Advanced cardiac life support o Current advanced cardiac life support (ACLS) guidelines recommend administration of oxygen and observation of the cardiac rhythm first. For bradycardias, Atropine may be indicated to speed up the heart rate, but remember to use Atropine with caution because increased heart rate increases myocardial O2 demand. External, transvenous, or permanent pacing may be needed for the treatment of bradycardia caused by heart block, especially third degree in which the atria and ventricles are not communicating & pacing themselves independently.
1. On a telemetry monitor, the nurse observes that a patient's heart rhythm is sustained ventricular tachycardia (VT). Upon assessment, the patient is alert and oriented with no reports of chest pain, but expresses feeling slightly short of breath. His blood pressure is 108/70. What is the nurse's first action? A. Synchronized cardioversion B. CPR and immediate defibrillation C. Administration of IV amiodarone (Cordarone) and dextrose D. Administration of oxygen and observation of the heart rhythm
D - Current advanced cardiac life support (ACLS) guidelines recommend administration of oxygen and observation of heart rhythm first, followed by administration of an IV antidysrhythmic agent such as amiodarone mixed with dextrose 5%. Synchronized cardioversion would be the next step. CPR and immediate defibrillation would be used only to treat unstable VT.
what are premature atrial complexes
Ectopic focus of atrial tissue fires an impulse before next sinus impulse is due. Premature atrial complexes can contribute to an irregular pattern as well. These premature complexes result when an ectopic focus of atrial tissue fires an impulse before next sinus impulse is due. See the tiny p-wave below the arrow is shaped differently from the others. Because it has a different morphology and occurs early, we recognize this as ectopic atrial stimulation. Notice also the slight delay before the SA node picks back up. If you measured, you would find that the normal p-waves march out regularly, and one is hidden by the QRS that responded to the ectopic beat. Remember though, you will not be required to measure on the exam.
what is left atrial appendage closure
For patients who are high risk for stroke and who are not candidates for anticoagulation, the left atrial appendage (LAA) occlusion device may be an option (Cheng & Hijazi, 2015). The LAA is a small sac in the wall of the left atrium. For those with nonvalvular AF, the LAA is the most common site of blood clot development leading to the risk of stroke. Inserted percutaneously via the femoral vein, a device to occlude the LAA is delivered via a transseptal puncture. In the United States, the Watchman, (nitinol frame with fenestrated fabric) is the only device approved for use in atrial fibrillation patients. After insertion, anticoagulation with aspirin and warfarin is required. A repeat TEE is performed approximately 45 days after insertion to assess for leaks around the device. If no leak is detected, the warfarin is stopped, and antiplatelet therapy is continued. Complications are similar to those for undergoing cardiac ablation procedure
What are atrial dysrhythmias?
In patients with atrial dysrhythmias, the focus of impulse generation shifts away from the sinus node to the atrial tissues. The shift changes the axis (direction) of atrial depolarization, resulting in a P-wave shape that differs from normal P waves. The most common atrial dysrhythmias are: · Premature atrial complexes · Supraventricular tachycardia Atrial fibrillation
what can cause abnormal heart rhythms
Many health problems, especially coronary artery disease (CAD), electrolyte imbalances, impaired gas exchange, and drug toxicity (both legal and illicit drugs)
what is normal sinus rhythm (NSR)
Normal sinus rhythm. Both atrial and ventricular rhythms are essentially regular (a slight variation in rhythm is normal). Atrial and ventricular rates are both 83 beats/min. There is one P wave before each QRS complex, and all the P waves are of a consistent morphology, or shape. The PR interval measures 0.18 second and is constant; the QRS complex measures 0.06 second and is constant. · Rate: 60 to 100 beats/min · Rhythm: Regular · P waves: Present, consistent configuration, one P wave before each QRS complex · PR interval: 0.12 to 0.20 second and constant · QRS duration: 0.04 to 0.10 second and constant
what are the ECG complexes, segments, and intervals
P wave PR segment PR interval QRS complex QRS duration ST segment T wave U wave QT interval
what are the concepts
PERFUSION FLUID AND ELECTROLYTE BALANCE CLOTTINGH
what happens when the heart does not work effectively as the pump
PERFUSION to vital organs and peripheral tissues can be impaired, resulting in organ dysfunction or failure
what is the bundle of HIS
Right bundle branch system: system extends down the right side of interventricular septum (which is left in this anatomical diagram facing the heart). The right bundle branch is responsible for conduction to right ventricle Left bundle branch system: system extends down the left side of interventricular septum before dividing to conduct across left ventricle.
what is the problem with dysrhythmias
The problem with dysrhythmias of any kind is they decrease cardiac output, because the heart is unable to function optimally in the way it is designed to synchronize.
what is bi-ventricular pacing
This type of pacing may be another alternative for patients with heart failure and conduction disorders. Biatrial pacing, anti-tachycardia pacing, and implantable atrial defibrillators are other methods used to suppress or resolve AF.
what is vagal stimulation
Vagal maneuvers stimulate the vagus nerve, which you recall from slide 8 causes decreased chronotropy. If you have trouble remembering what that means, think chronos is the Greek or Latin word for time. So decreased chronotropy means slower, and increased means faster. You may see physicians perform Carotid massage to stimulate the autonomic nervous system in the barrow receptors in those vessels. However, recalling the potential for embolization of a clot when the atria convert to a more effective rhytm, and knowing the association with carotid occlusion and stroke, we don't want family members to focus on our massaging on the carotids as the last thing that occurred before the client suffered a stroke. The vagal maneuvers that are safe for nurses to encourage are Valsalva (or bearing down as if to have a bowel movement), gagging, or ice to the face. Stroke and PE are still risks for a hyper-coagulable client, but the inferences are minimized. If you've ever had a client or family member pass out on the toilet, you can attest to the effectiveness of Valsalva as a vagal stimulant.
what is radio frequency catheter ablation
also requires informed consent; because this is an invasive procedure by which the irritable focus is identified and current is used to destroy the disruptive cells. The prep for this procedure is much the same as for coronary angiography, since a catheter is passed through a sheath in a large femoral vein.
what are cardiac dysrhythmias
are abnormal rhythms of the heart's electrical system that can affect its ability to effectively pump oxygenated blood throughout the body. Some dysrhythmias are life threatening, and others are not. They are the result of disturbances in cardiac electrical impulse formation, conduction, or both.
what are ventricular dysrhythmias
are generally more life-threatening than atrial dysrhythmias; because the ventricles are responsible for keeping circulation moving forward. The right ventricle perfuses the lungs allowing for gas exchange, and the left ventricle pumps oxygenated blood through the body to perfuse vital organs and other tissues. -Premature ventricular complexes -Ventricular tachycardia -Ventricular fibrillation -Ventricular asystole -More life-threatening than atrial dysrhythmias Left ventricle pumps oxygenated blood through the body to perfuse vital organs and other tissues
What are tachydysrhythmias?
are heart rates greater than 100 beats/min. They are a major concern in the adult patient with coronary artery disease (CAD). Coronary artery blood flow occurs mostly during diastole when the aortic valve is closed and is determined by diastolic time and blood pressure in the root of the aorta.
what are types of premature complexes
bigeminy trigeminy quadrigeminy
How does the heart perfuse the body
by being an intricate pump
what is the AV node
delays conduction to ventricles for optimal timing of contractions. Because of this delay, the assessment on the ECG is how long the PR segment is. You see, the boxes on ECG paper represent time in fractions of a second. Since the P-wave graphs firing of the SA node and the QRS graphs conduction through the ventricles, the number of boxes in between indicates how much of an atrioventricular delay is occurring between the two. The AV node may also take over for a dysfunctional SA Node. The result of this compensation is called a "junctional rhythm" and is usually slower than one generated from the SA node. PR segment on ECG Contraction known as "atrial kick"
what is the ECG rhythm analysis
determine heart rate determine heart rhythm analyze P waves measure PR Interval measures qrs duration interpret rhythm
what are the nonsurgical interventions for atrial dysrphtymias
electrical cardio version vagal stimulation left atrial appendage closure radiofrequency catheter ablation bi-ventricular pacing
what are the perkinje fibers
extend from both bundle branches to form an interwoven network on the endocardial surface of both ventricles and penetrate into the myocardium. These cells are responsible for the rapid conduction of electrical impulse throughout the ventricles, causing depolarization of cardiac cells that results in myocardial contraction. This depolarization is graphed as the QRS on an ECG. We frequently use the R wave in assessing heart rate on an ECG. Finally, the ST segment on the ECG graphs repolarization of myocardial cells in the ventricles.
what do ventricular dysrhythmias result from
from a hangry myocardium. When cardiac cells become stress or hypoxic their automaticity makes them able to act out. This irritability is sometimes progressive. shows an underlying sinus rhythm with unifocal premature ventricular complexes (PVCs) in strip A. Meaning, because they look alike, these early ventricularly generated impulses likely originated from the same irritable focus. In strip B, we see Normal sinus rhythm with multifocal PVCs (one negative and the other positive).In either case, you may notice what is referred to as a compensatory pause. In other words, if you marched the NSR beats out, you see that the sinus stimulus picks up right where it would have if the premature beat had not overridden the normal rhythm. PVCs tend to progress to repetitive rhythm complexes: Quadrigeminy (a PVC occurs every fourth beat), Trigeminy (every third beat is a PVC) and Bigeminy (every other beat is a PVC ). A couplet is two PVCs occurring in succession; three or more PVC is NSVT or nonsustained v-tach.
what is electrical cardioversion
involves the use of electric current to interrupt or override the dysrhythmic current & allow the sinus node to resume control. A counter-shock synchronized to the R-wave is delivered in emergency situations when the client with tachydysrhytmia is unstable. Synchronized cardioversion is often scheduled electively as well for clients whose tachydysrhythmia is resistant to medication therapy. Because Digoxin has a very long half-life & increases ventricular irritability, placing clients at risk for lethal dysrhythmia with cardioversion, Digoxin is usually held for 48 hours prior to elective cardioversion. Naturally, clients are anticoagulated to reduce risk of embolization upon conversion to an effective atrial rhythm; and TEE is often done prior to cardioversion to rule out any atrial thrombi that might have formed. This procedure requires informed consent due to potential risks. If hemodynamically stable, the client is often prescribed an antianxiety med like po valium, and conscious sedation is preferred, since cardioversion feels like one has been kicked in the chest.
what is contractility
is the ability of atrial and ventricular cardiac muscle cells to shorten their fiber length in response to electrical stimulation. This shortening results in contraction and facilitates the mechanical function of the heart. Because of its optimal cone shaped design, when functioning properly, this contractility causes sufficient pressure to force blood forward through the body. Also, contractility is increased in proportion to the amount of stretch (or preload) placed on the fibers just before contraction
what is the SA node
located in the right atrium. It is the primary cardiac pacemaker. Electrical impulses 60 to 100 beats/min P wave on ECG
what might the patient with tachydysrhythmias have
o Palpitations• Chest discomfort (pressure or pain from myocardial ischemia or infarction) • Restlessness and anxiety• Pale, cool skin• Syncope ("blackout") from hypotension · may also lead to heart failure. Presenting symptoms of heart failure may include dyspnea, lung crackles, distended neck veins, fatigue, and weakness
what is the planning and implementation of a patient with atrial dysrhythmias
o Preventing embolus formation o Preventing heart failure
why are tachydysrhythmias serious
o Shorten the diastolic time and therefore the coronary PERFUSION time (the amount of time available for blood to flow through the coronary arteries to the myocardium) o Initially increase cardiac output and blood pressure (However, a continued rise in heart rate decreases the ventricular filling time because of a shortened diastole, decreasing the stroke volume. Consequently, cardiac output and blood pressure will begin to decrease, reducing aortic pressure and therefore coronary PERFUSION pressure.) o Increase the work of the heart, increasing myocardial oxygen demand
what is automaticity
o ability to generate a electrical impulse spontaneously and repetitively. Normally, cardiac cells defer to the primary pacemaker (the SA node). In the absence of SA node stimulation, the AV node usually takes over as pacemaker. If neither is doing its job, the ventricular branches take over. The rate and appearance of the ECG rhythm differs depending on the origin of the impulse. We'll discuss this more later. Right now, it is important to know that the automaticity of all cardiac cells makes each cell able to generate and perpetuate an electrical impulse. So, when these cells become irritable, due to electrolyte imbalance, drug toxicity, ischemia (which is decreased perfusion) or infarction (which results in cell death) they can each stimulate themselves, resulting in chaotic and ineffective movement of the cardiac muscle wall.
what is bigeminy
o exists when normal complexes and premature complexes occur alternately in a repetitive two-beat pattern, with a pause occurring after each premature complex so complexes occur in pairs.
what is quadrigeminy
o is a repeated four-beat pattern, usually occurring as three sequential normal complexes followed by a premature complex and a pause, with the same pattern repeating itself in a four-beat pattern.
what is trigemini
o is a repeated three-beat pattern, usually occurring as two sequential normal complexes followed by a premature complex and a pause, with the same pattern repeating itself in triplets.
what is excitability
o is the ability of no-pacemaker cells to become excited. Cardiac cells can respond to an electrical impulse resulting in depolarization. It is depolarization that causes contraction, and it occurs as a result of an exchange of electrolytes across the cell membrane. During depolarization, negatively charged cells become positively charged due to an influx of Calcium. This may help you understand the action of calcium channel blockers, and why electrolyte balance is so important to normal cardiac function.
what is conductivity
o is the ability to transfer an electrical impulse from cell membrane to cell membrane, causing a wave of depolarization throughout the myocardium. These excitable cells depolarize in rapid succession; and it is this wave of depolarization causes the deflection we see on the ECG. Disturbances in conductivity cause dysrhythmias. If the successive depolarization occurs too rapidly, tachycardia results. Conduction that occurs too slowly can result in bradycardia. Conduction can also be delayed or completely blocked resulting in some of the "heart blocks" we will discuss later. Complete dysfunction occurs when conduction is stopped. Remember, all cardiac cells have the ability to generate an electrical impulse. Although they normally respond to the stronger impulse of the primary pacemaker, if cardiac cells are not stimulated by conduction, they generate their own impulse. Imagine the chaos when each cell starts generating and perpetuating its own depolarization. This results in what we know as fibrillation I which the myocardium sort of quivers ineffectively. Now, when this occurs in the atria (aka atrial fibrillation) it can result in complications such as blood clot formation, but some client's live decades with controlled atrial fib. However, when this fibrillation occurs in the ventricles, complete pump failure results. Thus, Ventricular fibrillation is a LETHAL arrhythmia.
what is the interprofessional care of atrial dysrhythmias
our patient-centered collaborative care should anticipate risk for Pulmonary Embolism, and for Venous Thromboembolism. As mentioned before, it is possible for clots to form in the atria during episodes of impaired atrial emptying such as rapid atrial fib. What happens when such a clot is kicked out of the right atrium? Right, it follows through the cardiac circulation to the pulmonary circulation to form a PE. So, if a clot forms in the left atrium? The most significant risk is stroke as the carotids branch right off the aorta to perfuse the brain. So, we want to control clotting, as well as control dysrhythmias
what are common dysrhythmias
premature complexes bradydysrhythmias tachdysrhythmias
how do you analyze P waves
should look like each other (called consistent configuration)
what are parts of the cardiac conduction system
sinoatrial node (SA node) atrioventricular junction (AV node) bundle of his perkinje fibers
what are types of pacemakers
temporary pacing permanent
what is the U wave
when present, represents late ventricular repolarization
what is the P wave
· (that first little blip) represents atrial depolarization in response to impulse from the SA node. So, a client whose rhythm is initiated from a site other than the SA node (such as ventricular tachycardia) will not have P-waves.
what is the T wave
· : Represents ventricular repolarization, or return to asystole
what is the ST segment
· An elevated ST segment (which is highly indicative of myocardial infarction) represents early ventricular repolarization, or return to asystole. Think about this. The damaged myocardial cells are unable to depolarize or achieve systole. So, repolarization is evidenced earlier in the ECG cycle.
how do you determine heart rhythm
· Assess for atrial and/or ventricular regularity. Heart rhythms can be either regular or irregular. Irregular rhythms can be regularly irregular, occasionally irregular, or irregularly irregular. Check the regularity of the atrial rhythm by assessing the PP intervals, placing one caliper point on a P wave and the other point on the precise spot on the next P wave. Then move the caliper from P wave to P wave along the entire strip ("walking out" the P waves) to determine the regularity of the rhythm. P waves of a different shape (ectopic waves), if present, create an irregularity and do not walk out with the other P waves. A slight irregularity in the PP intervals, varying no more than three small blocks, is considered essentially regular if the P waves are all of the same shape. This alteration is caused by changes in intrathoracic pressure during the respiratory cycle.Check the regularity of the ventricular rhythm by assessing the RR intervals, placing one caliper point on a portion of the QRS complex (usually the most prominent portion of the deflection) and the other point on the precise spot of the next QRS complex. Move the caliper from QRS complex to QRS complex along the entire strip (walking out the QRS complexes) to determine the regularity of the rhythm. QRS complexes of a different shape (ectopic QRS complexes), if present, create an irregularity and do not walk out with the other QRS complexes. A slight irregularity of no more than three small blocks between intervals is considered essentially regular if the QRS complexes are all of the same shape.
what are heart blocks
· Blockages of electrical impulse from the atria to the ventricles commonly result in bradycardia, and the degree is differentiated by the PR intervals. In first-degree block, all sinus impulses eventually reach ventricles, there is just a delay between the p-wave and the QRS. In both types of second-degree block, some sinus impulses reach ventricles, but others do not. However, in third-degree block, there is no communication; so, no sinus impulses reach ventricles. The atria are doing their own thing, while the ventricles plug along at their inherent rate of 20-40 bpm. Clients in third degree block will need a pacemaker; so, provide supplemental O2, apply the transcutaneous pads, call the provider, and prepare for a more permanent means of pacing.
what is the incidence and prevalence of afib
· Currently, about 2.7 to 6.1 million people in the United States are diagnosed with AF; it occurs more often in those of European ancestry and African Americans (January et al., 2014). The incidence of AF increases with age; it causes serious problems in older people, leading to stroke and/or heart failure. Risk factors include hypertension (HTN), previous ischemic stroke, transient ischemic attack (TIA) or other thromboembolic event, coronary heart disease, diabetes mellitus, heart failure, obesity, hyperthyroidism, chronic kidney disease, excessive alcohol use, and mitral valve disease. o Most common dysrhythmia o Incidence increases with age
what is sinus bradycardia
· Excessive vagal (parasympathetic) stimulation to the heart causes a decreased rate of sinus node discharge. It may result from carotid sinus massage, vomiting, suctioning, Valsalva maneuvers (e.g., bearing down for a bowel movement or gagging), ocular pressure, or pain. Increased parasympathetic stimuli may also result from hypoxia, inferior wall MI, and the administration of drugs such as beta-adrenergic blocking agents, calcium channel blockers, and digitalis. Lyme disease, ELECTROLYTE disturbances, neurologic disorders, and hypothyroidism may also cause bradycardia. · The stimuli slow the heart rate and decrease the speed of conduction through the heart. When the sinus node discharge rate is less than 60 beats/min, the rhythm is called sinus bradycardia (Fig. 34- 8B). Sinus bradycardia increases coronary PERFUSION time, but it may decrease coronary perfusion pressure. However, myocardial oxygen demand is decreased. Well-conditioned athletes with bradycardia have a hypereffective heart in which the strong heart muscle provides an adequate stroke volume and a low heart rate to achieve a normal cardiac output.
what is the pathophysiology of afib
· In patients with AF, multiple rapid impulses from many atrial foci depolarize the atria in a totally disorganized manner at a rate of 350 to 600 times per minute; ventricular response is usually 120 to 200 beats/min. The result is a chaotic rhythm with no clear P waves, no atrial contractions, loss of atrial kick, and an irregular ventricular response (Fig. 34-11). The atria merely quiver in fibrillation (commonly called A fib). Often the ventricles beat with a rapid rate in response to the numerous atrial impulses. The rapid and irregular ventricular rate decreases ventricular filling and reduces cardiac output. This alteration in cardiac function allows for blood to pool, placing the patient at risk for CLOTTING concerns such as DVT or PE. AF is frequently associated with underlying cardiovascular disease o Chaotic rhythm o No clear p wave o Irregular ventricular response
what is the analysis of a patient with atrial dysrhythmias
· Interpreting: Assess patients who have chronic atrial fibrillation for methods of coping with a long-term conduction issue. Patients with chronic AF may have anxiety related to anticoagulation medications and the potential for emboli development. o Potential for embolus formation due to irregular cardiac rhythm o Potential for heart failure due to altered conduction pattern
what is atrial fibrillation
· Note wavy baseline with atrial electrical activity and irregular ventricular rhythm. Atrial fib is the most commonly seen dysrhythmia in clinical practice, and clients are often asymptomatic. Contributing factors are atrial fibrosis or loss of cardiac muscle mass resulting from HTN, heart failure, & CAD. AF becomes problematic for two reasons. First, you know that any dysrhythmia interferes with optimal cardiac output, and AF can cause as much as 30% reduction in CO. Also, consider what happens to the blood that remains in the atria because of this ineffective emptying. When blood sits still, it clots/ or coagulates, right? This is why we see anticoagulants (like ASA, Coumadin, Pradaxa, Xarelto, Eliquis, etc) on the med lists of so many clients with a history of A-fib. Note the absence of antidote for the NOAC (novel oral anticoagulant) drugs discussed on pg. 680. What is the antidote for Coumadin therapy? Right, Aqua-Mephyton or Vitamin K. The disadvantage to Coumadin, over these newer therapies, is the requirement for continual assessment of Coumadin's effectiveness with INR, to ensure a therapeutic range.
what is the assessment of atrial dysrhythmias
· Noticing: On physical examination, the apical pulse may be irregular. Symptoms depend on the ventricular rate. Because of the loss of atrial kick, the patient in uncontrolled AF is at greater risk for inadequate cardiac output. Signs of poor PERFUSION may be seen. Assess the patient for fatigue, weakness, shortness of breath, dizziness, anxiety, syncope, palpitations, chest discomfort or pain, and hypotension. Some patients may be asymptomatic. Patients with AF, especially those with a high ventricular rate, can feel very anxious. With increased heart rate, cardiac output decreases, which can create dyspnea, contributing to feelings of anxiety o Signs of poor perfusion o Anxiety o 12 lead ECG
how do you interpret rhythm
· Once we know what normal is, we can interpret the rhythm by analyze P waves, measuring PR intervals, measure QRS duration, and assessing our patient.
what are permanent pace makers
· Permanent pacemaker insertion is performed to treat conduction disorders that are not temporary, including complete heart block. These pacemakers are usually powered by a lithium battery and have an average life span of 10 years. After the battery power is depleted, the generator must be replaced by a procedure done with the patient under local anesthesia. Some pacemakers are nuclear powered and have a life span of 20 years or longer. Other pacemakers can be recharged externally. Combination pacemaker/defibrillator devices are also available.
what is supraventricular tachycardia
· Rapid stimulation of atrial tissue occurs at rate of 100 to 280 beat/min with mean of 170 beats/min (adults) · Paroxysmal supraventricular tachycardia rhythm is intermittent, terminated suddenly with or without intervention · " SVT was differentiated from Sinus tachycardia using the following tips: Sinus tach has a rate of 100 to 150 beats per minute; and SVT has a rate of 151 to 250 beats per minute. In sinus tach, the P waves and T waves identifiable; but in SVT, the p-wave may be absent or hidden in the t-wave of the preceding complex. Although these are not bad rules of thumb, it is more important to assess your client while considering these four criteria: the presenting complaint (can the tachycardia be explained? (Such as fever, hypoxia, or anaerobic exercise like one running from a burning building) Or, is there no obvious reason (As in a nursing student complaining that her heart suddenly started racing while reviewing notes on Iggy. Her heart rate is 160 bpm; her breathing is normal, and her skin is warm and dry.) This sudden onset is the second criteria to consider; because sinus tach usually develops in response to O2 demands for increased C.O.; whereas, SVT is commonly paroxysmal, meaning intermittent with sudden onset and sometimes abrupt termination of tachycardia. Third, look for rate variability, as once SVT starts, the rate tends to stay the same until return to a sinus rhythm. Whereas, sinus tach varies in response to metabolic demands. Finally, look closely for p-waves; because sinus tach and most SVTs have only one P wave for each QRS complex. Although p-waves may or may not be buried in the preceding T waves, some supra-ventricular tachycardias (like rapid atrial fib) have no distinguishable P waves; while others may have more than one P wave for each QRS (like rapid atrial flutter shown with the characteristic saw tooth pattern in the second strip). Remember also that atrial fib is "regularly irregular", while most other SVT syndromes have a regular pattern. "
what is the evaluation of atrial dysrphtymias
· Remain free of embolus formation · Remain free of heart failure with regular heart rate and rhythm
what are PVCS
· Result of increased irritability of ventricular cells—early ventricular complexes followed by a pause also called premature ventricular contractions, result from increased irritability of ventricular cells and are seen as early ventricular complexes followed by a pause. When multiple PVCs are present, the QRS complexes may be unifocal or uniform, meaning that they are of the same shape (Fig. 34-12A), or multifocal or multiform, meaning that they are of different shapes (Fig. 34-12B). PVCs frequently occur in repetitive rhythms, such as bigeminy (two), trigeminy (three), and quadrigeminy (four). Premature ventricular contractions are common, and their frequency increases with age. They may be insignificant or may occur with problems such as myocardial infarction, chronic heart failure, chronic obstructive pulmonary disease (COPD), and anemia. PVCs may also be present in patients with hypokalemia or hypomagnesemia. Sympathomimetic agents, anesthesia drugs, stress, nicotine, caffeine, alcohol, infection, or surgery can also cause PVCs, especially in older adults. Postmenopausal women often find that caffeine causes palpitations and PVCs.
what are sinus dysrhythmias
· Sinus tachycardia · Sinus bradycardia
what is sinus tachycardia
· Sympathetic nervous system stimulation or vagal (parasympathetic) inhibition results in an increased rate of SA node discharge, which increases the heart rate. When the rate of SA node discharge is more than 100 beats/min, the rhythm is called sinus tachycardia (Fig. 34-8A). From age 10 years to adulthood, the heart rate normally does not exceed 100 beats/min except in response to activity and then usually does not exceed 160 beats/min. Rarely does the heart rate each 180 beats/min. · Sinus tachycardia initially increases cardiac output and blood pressure. However, continued increases in heart rate decrease coronary PERFUSION time, diastolic filling time, and coronary PERFUSION pressure while increasing myocardial oxygen demand. · Increased sympathetic stimulation is a normal response to physical activity but may also be caused by anxiety, pain, stress, fever, anemia, hypoxemia, and hyperthyroidism. Drugs such as epinephrine, atropine, caffeine, alcohol, nicotine, cocaine, aminophylline, and thyroid medications may also increase the heart rate. In some cases, sinus tachycardia is a compensatory response to decreased cardiac output or blood pressure, as occurs in dehydration, hypovolemic shock, myocardial infarction (MI), infection, and heart failure. Assess patients for signs and symptoms of hypovolemia and dehydration, including increased pulse rate, decreased urinary output, decreased blood pressure, and dry skin and mucous membranes.
how do you measure QRS duration
· The QRS complexes should be narrow, with a duration of 0.04-0.10 seconds (usually 1-2 tiny boxes between points Q&T).
what are sinus arrhythmias
· Variant of NSR · Results from changes in intrathoracic pressure during breathing · In this context, the term arrhythmia does not mean an absence of rhythm, as the term suggests. Instead, the heart rate increases slightly during inspiration and decreases slightly during exhalation. This irregular rhythm is frequently observed in healthy adults. Sinus arrhythmia has all the characteristics of NSR except for its irregularity. The PP and RR intervals vary, with the difference between the shortest and the longest intervals being greater than 0.12 second (three small blocks):
what are premature complexes
· are early rhythm complexes. They occur when a cardiac cell or cell group, other than the sinoatrial (SA) node, becomes irritable and fires an impulse before the next sinus impulse is produced. The abnormal focus is called an ectopic focus and may be generated by atrial, junctional, or ventricular tissue. After the premature complex, there is a pause before the next normal complex, creating an irregularity in the rhythm. The patient with premature complexes may be unaware of them or may feel palpitations or a "skipping" of the heartbeat. If premature complexes, especially those that are ventricular, become more frequent, the patient may experience symptoms of decreased cardiac output. Premature complexes may occur repetitively in a rhythmic fashion:
what is a temporary pacemaker
· invasive and noninvasive: is a nonsurgical intervention that provides a timed electrical stimulus to the heart when either the impulse initiation or the conduction system of the heart is defective. The electrical stimulus then spreads throughout the heart to depolarize the cells, which should be followed by contraction and cardiac output. Electrical stimuli may be delivered to the right atrium or right ventricle (single-chamber pacemakers) or to both (dual-chamber pacemakers). Temporary pacing is used for patients with symptomatic bradydysrhythmias who do not respond to atropine or for patients with asystole. There are two types of temporary pacing: transcutaneous and transvenous.
what is the QRS duration
· measures the time required for ventricular depolarization. QRS duration is measured from the beginning of the Q wave to the end of the S wave
What are bradydysrhythmias?
· occur when the heart rate is less than 60 beats/min. These rhythms can also be significant because: o Myocardial oxygen demand is reduced from the slow heart rate, which can be beneficial. o • Coronary PERFUSION time may be adequate because of a prolonged diastole, which is desirable. o • Coronary perfusion pressure may decrease if the heart rate is too slow to provide adequate cardiac output and blood pressure; this is a serious consequence. o Therefore the patient may tolerate the bradydysrhythmia well if the blood pressure is adequate. If the blood pressure is not adequate, symptomatic bradydysrhythmias may lead to myocardial ischemia or infarction, dysrhythmias, hypotension, and heart failure.
what is the PR interval
· represents the time required for atrial depolarization and transmission of the impulse to the ventricles. The PR interval is measured from the start of the P-wave to the start of the Q-wave.
what is the PR segment
· represents the time that an impulse to travel through the AV node, just before the ventricles are depolarized.
what is the QT interval
· represents the total time required for ventricular depolarization and repolarization. The QT interval is measured from the start of the Q wave to the end of the T-wave. Precautions for many of the drugs you are studying list "prolonged QT interval" as a potential side effect. Since a prolonged QT can potentially cause fast, chaotic dysrhythmias, a prudent nurse might collaborate to place clients receiving such therapies on telemetry.
what is the QRS complex
· represents ventricular depolarization which should cause contraction or systole.
how do you measure PR interval
· the QRS should consistently follow each P-wave within 3 - 5 tiny boxes (0.12-0.20 second)
what is an ECG
Ø Electrocardiography is a recording of electrical activity in the heart. When myocardial cell damage occurs, the electrical conduction becomes altered. Correlation of ECG changes with various diagnoses has enabled healthcare providers to interpret cardiovascular problems based on a graph of the conduction of electricity through the myocardium. On ECG, location of abnormality in certain wave-forms can indicate the type of dysfunction. For example, T-wave inversion can indicate ischemia, ST segment elevation is significant for diagnosis of MI, and prolonged Q-wave can indicate extension of the damage. It is also important to determine which part of the myocardium the problem is occurring. ECG is helpful for this as well.
