EKG taller NCLEX fast prep

A nurse is watching the cardiac monitor, and a client’s rhythm suddenly changes. There are no P waves; instead, there are wavy lines. The QRS complexes measure 0.08 second, but they are irregular, with a rate of 120 beats a minute. The nurse interprets this rhythm as:

• Sinus tachycardia

• Atrial fibrillation

• Ventricular tachycardia

• Ventricular fibrillation

Answer explanation

Correct Answer: B. Atrial fibrillation

Atrial fibrillation is characterized by a loss of P waves; an undulating, wavy baseline; QRS duration that is often within normal limits; and an irregular ventricular rate, which can range from 60 to 100 beats per minute (when controlled with medications) to 100 to 160 beats per minute (when uncontrolled). Atrial fibrillation is the most common type of cardiac arrhythmia. It is the leading cardiac cause of stroke. Risk factors for atrial fibrillation include advanced age, high blood pressure, underlying heart and lung disease, congenital heart disease, and increased alcohol consumption.

• Option A: Sinus tachycardia is a regular cardiac rhythm in which the heart beats faster than normal and results in an increase in cardiac output. While it is common to have sinus tachycardia as a compensatory response to exercise or stress, it becomes concerning when it occurs at rest.

• Option C: Ventricular tachycardia is characterized by the absence of P waves, wide QRS complexes (usually greater than 0.14 second), and a rate between 100 and 250 impulses per minute. The rhythm is usually regular. Ventricular tachycardia is characterized as a wide complex (QRS duration greater than 120 milliseconds) tachyarrhythmia at a heart rate greater than 100 beats per minute. It is classified by duration as non-sustained or sustained. Non-sustained ventricular tachycardia is defined as more than 3 beats of ventricular origin at a rate greater than 100 beats per minute that lasts less than 30 seconds in duration.

• Option D: VF is a WCT caused by irregular electrical activity and characterized by a ventricular rate of usually greater than 300 with discrete QRS complexes on the electrocardiogram (ECG). QRS morphology in VF varies in shape, amplitude, and duration with a prominent irregular rhythm.

The adaptations of a client with complete heart block would most likely include:

• • Nausea and vertigo

• • Flushing and slurred speech

• • Cephalalgia and blurred vision

• • Syncope and slow ventricular rate

Answer explanation

Correct Answer: D. Syncope and slow ventricular rate

In complete atrioventricular block, the ventricles take over the pacemaker function in the heart but at a much slower rate than that of the SA node. As a result, there is decreased cerebral circulation, causing syncope. Patients with third-degree blocks can have varying clinical presentations. Rarely, patients are asymptomatic. Usually, they may present with generalized fatigue, tiredness, chest pain, shortness of breath, presyncope, or syncope. They may have significant hemodynamic instability and can be obtunded.

• Option A: The physical exam is usually remarkable for bradycardia. JVP examination often demonstrates cannon A-waves owing to the simultaneous contraction of the atria and ventricles. Thus a very large pressure wave is felt up against the vein.

• Option B: Especially with heart rates below 40/min, patients might also present with features consistent with decompensated heart failure, respiratory distress, and hypoperfusion such as diaphoresis, tachypnea, altered mental status, retraction, cool skin, and decreased capillary refill.

• Option C: Patients with complete AV-block accompanying an acute myocardial infarction often have ischemic symptoms of chest pain or dyspnea. The past medical history will often include the presence of cardiovascular disease and/or its risk factors, including diabetes mellitus, hypertension, dyslipidemia, and smoking, etc.

What criteria should the nurse use to determine normal sinus rhythm for a client on a cardiac monitor? Select all that apply.

• • The RR intervals are relatively consistent.

• • One P wave precedes each QRS complex.

• • Four to eight complexes occur in a 6-second strip.

• • The ST segment is higher than the PR interval.

• • The QRS complex ranges from 0.12 to 0.20 second.

Answer explanation

Correct Answers: A, B.

The consistency of the RR interval indicates regular rhythm. A normal P wave before each complex indicates the impulse originated in the SA node. Sinus arrhythmia is most typically present in young, healthy individuals. Studies have attempted to establish an increased prevalence in patients with underlying hypertension, obesity, and diabetes.

• Option A: Sinus rhythm (a.k.a. normal sinus rhythm) refers to the normal heart beat originating from the sinoatrial node. This is manifested as an upright P wave in lead II of the ECG. Sinus arrhythmia is a common rhythm variation. It is seen more often in children and young adults. Respirations lead to vagal stimuli resulting in R-R interval variations.

• Option B: Sinus arrhythmia is a commonly encountered variation of normal sinus rhythm. Sinus arrhythmia characteristically presents with an irregular rate in which the variation in the R-R interval is greater than 0.12 seconds. Additionally, P waves are typically monoform and in a pattern consistent with atrial activation originating from the sinus node.

• Option C: The number of complexes in a 6-second strip is multiplied by 10 to approximate the heart rate; normal sinus rhythm is 60 to 100. On the EKG, sinus rhythm appears as a beat-to-beat variation in the P-P interval. Typically, this variation is greater than 120 msec: the P-P interval increases and decreases with inspiration and exhalation.

• Option D: Elevation of the ST segment is a sign of cardiac ischemia and is unrelated to the rhythm. The ST Segment represents the interval between ventricular depolarization and repolarization. The most important cause of ST segment abnormality (elevation or depression) is myocardial ischaemia or infarction.

• Option E: The QRS duration should be less than 0.12 second; the PR interval should be 0.12 to 0.20 second. The normal duration (interval) of the QRS complex is between 0.08 and 0.10 seconds — that is, 80 and 100 milliseconds. When the duration is between 0.10 and 0.12 seconds, it is intermediate or slightly prolonged. A QRS duration of greater than 0.12 seconds is considered abnormal.

A patient is experiencing sinus bradycardia with a rate of 34 bpm and blood pressure of 78/42. The patient reports symptoms of chest pain, has cool and clammy skin, dyspnea, and feels like they may faint. The nurse prepares to administer Atropine per a standing physician's order for the patient's symptomatic bradycardia. How will the nurse administer this medication?

• 3 mg IV push every 3-5 minutes, max dose of 5 mg

• 2 mg IV push every 1-2 minutes, max dose of 3 mg

• 3-5 mg IV push every 1 minute, max dose 10 mg

• 1 mg IV push every 3-5 minutes, max dose of 3 mg

Answer explanation

The answer is D: Atropine for symptomatic bradycardia should be given as 1 mg IV push every 3-5 minutes, max dose of 3 mg.

Referring back to the previous question, Atropine was ineffective for treating the bradycardia. The patient is still symptomatic with a rate 35 bpm. What other options could be considered for the patient? Select all that apply:

• Transcutaneous pacing

• Amiodarone Infusion

• Dopamine Infusion

• Epinephrine Infusion

Answer explanation

The answers are A, C, and D.