Cardiology: Electrical Spread & Antithrombotic Therapy

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Questions and Answers

What is the purpose of a cardiac arrest/emergency alarm button in the ICU?

To facilitate social interactions among staff

To replace the need for bedside monitoring equipment

To notify the nursing staff in a timely manner (correct)

To provide entertainment for patients

Which of the following is NOT a component of prearrival assessment for ICU patients?

Surgical history (correct)

General communication

Chief complaint

Status of laboratory tests

What aspect of critical care involves reducing patient stress through communication?

Emergency alarm systems

Expertise supportive care

Anticipatory nursing care (correct)

Crisis intervention

Why is early detection emphasized in critical care nursing?

To initiate prompt medical intervention Signup and view all the answers

Which component is involved in the preservation of a patient’s physiological defenses?

Supportive care practices Signup and view all the answers

What should be included in the spirituality assessment of ICU patients?

Faith/spiritual preference Signup and view all the answers

Which system is central for notifying the staff of emergencies in the ICU?

Hospital telecommunications center Signup and view all the answers

Which of the following items is typically checked regarding equipment status during the prearrival assessment?

Functionality of ventilators Signup and view all the answers

What does a positive QRS complex indicate regarding the isoelectric line?

Area above the isoelectric line is larger. Signup and view all the answers

How is the cardiac axis approximated?

By evaluating combinations of QRS complex polarities in leads I and aVF. Signup and view all the answers

What is indicated by a left axis deviation?

Positive in lead I and negative in aVF. Signup and view all the answers

What is the primary cause of distributive shock due to hyperergic reactions?

Allergic reactions to antigens Signup and view all the answers

What does a negative QRS complex indicate?

Area below the isoelectric line is larger. Signup and view all the answers

What does one large box on the ECG paper represent?

0.2 seconds Signup and view all the answers

Which of the following conditions might require antithrombotic therapy?

All patients with AF. Signup and view all the answers

How long does one small box on the ECG paper represent?

40 milliseconds Signup and view all the answers

What INR range is targeted for chronic oral anticoagulant therapy with vitamin K antagonists?

2.0 to 3.0 Signup and view all the answers

What is the significance of measuring the vertical height of the ECG waveform?

To assess the amplitude of electrical signals Signup and view all the answers

Which of the following is NOT a condition that generally requires antithrombotic therapy?

Patients with lone AF. Signup and view all the answers

In which situation is anticoagulation with a vitamin K antagonist generally recommended?

In patients with mechanical heart valves. Signup and view all the answers

Which interval does a large box contain on the ECG?

200 milliseconds Signup and view all the answers

What can disturbances in the heart's electrical activity lead to?

Arrhythmias and potential death Signup and view all the answers

What do the small squares on the ECG represent?

0.04 seconds Signup and view all the answers

What is the height measurement of a large box in millivolts on ECG paper?

0.5 Mv Signup and view all the answers

What does the S-T segment represent in an ECG reading?

The interval between ventricular depolarization and repolarization Signup and view all the answers

Which condition is associated with significant S-T elevation?

ST-Elevation Myocardial Infarction (STEMI) Signup and view all the answers

What appearance does a normal S-T segment typically have?

Horizontal isoelectric line with upward slope Signup and view all the answers

In which leads is the U wave best seen?

Leads V2 to V4 Signup and view all the answers

What is a common cause of S-T elevation in patients with pulmonary embolism?

S-T elevation due to myocardial stretch Signup and view all the answers

What does the U wave represent in ECG readings?

Delayed repolarization of myocardial cells Signup and view all the answers

Which of the following conditions can lead to widespread S-T elevation throughout the ECG?

Pericarditis Signup and view all the answers

What is the characteristic of the J point in an ECG?

It represents the end of the QRS complex Signup and view all the answers

What condition may be suggested by changes in P wave morphology?

Wandering Pacemaker Signup and view all the answers

Which of the following heart rhythms is characterized by narrow QRS complexes that are not preceded by P waves?

AV Nodal or Junctional Rhythm Signup and view all the answers

What happens if the sinus node fails to initiate the impulse?

The AV node takes over as the pacemaker. Signup and view all the answers

What does an inverted P wave after the QRS complex indicate?

Retrograde conduction Signup and view all the answers

Which of the following has the fastest automaticity?

SA Node Signup and view all the answers

If both the sinus node and the atrial focus fail, which part of the heart assumes pacemaker control next?

AV Node Signup and view all the answers

Which rhythm is characterized by wide QRS complexes that are also not preceded by P waves?

Ventricular Rhythm Signup and view all the answers

In what scenario does the heart rhythm become non-sinus?

When impulse is initiated from the atrial focus. Signup and view all the answers

Study Notes

Electrical Spread in the Heart

The cardiac axis indicates the mean direction of ventricular depolarization in the frontal plane.
Positive QRS Complex indicates that the area above the isoelectric line is larger than below; Negative QRS Complex indicates the opposite.
Cardiac axis approximated by evaluating QRS complex polarities in leads I and aVF:
- Positive in both leads indicates normal axis.
- Positive in lead I and negative in aVF suggests left axis deviation.
- Negative in lead I and positive in aVF suggests right axis deviation.
- Negative in both leads indicates extreme right axis deviation.

Antithrombotic Therapy

Recommended for all patients with Atrial Fibrillation (AF) except those with lone AF or contraindications.
Chronic oral anticoagulant therapy with vitamin K antagonists targets an INR of 2.0 to 3.0, not advised for patients with mechanical heart valves.
Anticoagulation recommended for patients with multiple moderate risk factors (e.g., age >75, hypertension).

Principles of Critical Care Nursing

Emphasizes early detection, prompt action, and supportive care.
Includes crisis intervention and effective communication.
Ethical principles include preserving patient physiological defenses and preventing infection.

ICU Admission Process

Prearrivals and assessments should involve:
- Collecting general information including age, gender, chief complaints, and physiological status.
- Evaluating coping styles, anxiety levels, and family needs.
- Considering spiritual needs and preferences.

Shock Due to Hyperergic Reactions

Distributive shock develops from allergic reactions in hypersensitive patients.

ECG Reading and Interpretation

Electrocardiography (ECG) measures the heart's electrical activities using external electrodes.
Horizontal measures on ECG:
- Large Box: 5 mm wide represents 0.2 seconds.
- Small Box: 1 mm wide represents 0.04 seconds.
Vertical measures:
- Large Box: Represents 0.5 mV (millivolts), crucial for assessing amplitude of electrical signals.

Major Components of Heart's Electrical Activities

Baseline reference indicates ST segment elevation or depression.
Normal ST segment appears as a horizontal isoelectric line; it extends from the J point to the start of the T wave.
U wave appears after the T wave, polarity same as T wave; cause thought to be delayed repolarization.

STEMI associated with significant ST elevation.
LBBB can cause ST elevation; often normal in athletes.
Pulmonary embolism may result in ST elevation.
Brugada pattern is a distinct ECG pattern linked to sudden cardiac death.

Cardiac Rhythm Control

Myocytes exhibit inherent automaticity; SA node is the natural pacemaker.
The hierarchy of pacemaker control:
- SA Node → AV Node → Ventricles.
If the SA node fails, an atrial focus may take over, followed by the AV node if needed.

Atrial and Ventricular Rhythms

Atrial rhythm characterized by narrow QRS complexes; junctional rhythm shows narrow QRS without P waves.
Ventricular rhythm characterized by wide QRS complexes, indicating that it is not initiated by the sinus node.

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Description

This quiz covers essential concepts in cardiology, focusing on the electrical spread in the heart and the application of antithrombotic therapy. Learn about the cardiac axis, QRS complex interpretations, and guidelines for anticoagulation therapy in atrial fibrillation patients. Test your knowledge on these critical topics!