Cardiac Rhythm and Electrophysiology Quiz

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Questions and Answers

What is the primary function of the cardiac conduction system?

To detect external electrical signals

To maintain the pumping efficiency of the heart (correct)

To absorb nutrients for the heart tissues

To generate impulses for muscle contraction

What type of monitoring has been emphasized in continuous bedside cardiac monitoring?

Identification of ST segment changes and advanced arrhythmias (correct)

Assessment of physical symptoms and patient history

Basic rhythm detection

Only heart rate variability

What can significantly affect the diagnosis of cardiac arrhythmias during an ECG?

Type of ECG machine used

Medical history of the patient

Improper lead placement (correct)

Patient's blood pressure

Which statement about the SA node is accurate?

It generates the fastest rate of electrical impulses in the heart Signup and view all the answers

Which of the following statements is false regarding the electrocardiogram?

It provides definitive diagnosis of muscle activity defects. Signup and view all the answers

What are the main types of disorders associated with the cardiac conduction system?

Disorders of rhythm and impulse conduction Signup and view all the answers

Which of the following is NOT a cause of conduction system disorders?

Coronary artery dilation Signup and view all the answers

Which class of drugs primarily acts by blocking the fast sodium channels in the treatment of arrhythmias?

Class I drugs Signup and view all the answers

What type of arrhythmia includes conditions such as premature ventricular contractions and ventricular tachycardia?

Ventricular arrhythmias Signup and view all the answers

Which diagnostic method is specifically used for continuous monitoring of an individual's heart activity over an extended period?

Holter monitoring Signup and view all the answers

What therapeutic procedure is used to restore normal heart rhythms by delivering an electrical shock?

Cardioversion Signup and view all the answers

Which arrhythmia originates primarily in the sinus node?

Sinus bradycardia Signup and view all the answers

What treatment option is often used for patients with severe bradycardia?

Electronic pacemaker Signup and view all the answers

Study Notes

Cardiac Conduction and Rhythm Disorders

Cardiac Conduction System:
- Controls the rate and direction of electrical impulses in the heart.
- Impulses originate in the SA node (sinoatrial node), which has the fastest firing rate.
- Impulses travel to the Purkinje fibers in the ventricles.
- Specialized myocardial cells form the conduction system in specific areas of the heart to ensure efficient pumping.

Electrocardiography

Twelve Leads: Each provides a unique view of the heart's electrical forces.
Diagnostic ECG: Diagnostic criteria are specific to each lead.
Lead Placement: Improper placement significantly alters QRS morphology, potentially leading to misdiagnosis of arrhythmias and conduction defects.

Calculating Heart Rate from ECG

Count the number of "R" waves in 6 seconds.
Multiply by 10 to determine the heart rate per minute (6 large boxes = 1 minute).

Cardiac Electrophysiology

P-Wave: Represents atrial depolarization (contraction).
QRS Complex: Represents ventricular depolarization (contraction).
ST Segment: Represents the heart's resting period.
T-Wave: Represents ventricular repolarization (relaxation).
PR Interval: Period between atrial and ventricular depolarization.

Continuous Bedside Cardiac Monitoring

Improved from basic heart rate and arrhythmia monitoring to include:
- Identification of ST segment changes
- Advanced arrhythmia identification
- Diagnosis
- Treatment provision

ECG and Cardiac Muscle Contraction

False: The ECG reflects electrical activity, not directly cardiac muscle contraction. Specific defects in muscle activity cannot be directly diagnosed by ECG.

Types and Causes of Cardiac Conduction System Disorders

Types:
- Rhythm disorders
- Impulse conduction disorders
Causes:
- Congenital defects or degenerative changes in the conduction system
- Myocardial ischemia and infarction
- Fluid and electrolyte imbalances
- Drug effects

Types of Arrhythmias #1

Sinus Node Arrhythmias:
- Sinus bradycardia
- Sinus tachycardia
- Sinus arrest
Arrhythmias of Atrial Origin:
- Paroxysmal supraventricular tachycardia
- Atrial flutter
- Atrial fibrillation

Types of Arrhythmias #2

Junctional Arrhythmias
Disorders of Ventricular Conduction and Rhythm
Long QT Syndrome and Torsades de Pointes
Ventricular Arrhythmias:
- Premature ventricular contractions
- Ventricular tachycardia
- Ventricular flutter and fibrillation

Diagnostic Methods

Signal-averaged electrocardiogram
Holter monitoring
Exercise stress testing
Electrophysiologic studies
QT dispersion

Pharmacologic Treatment of Arrhythmias

Class I: Blocks fast sodium channels
Class II: Beta-adrenergic-blocking drugs
Class III: Extends action potential and refractoriness
Class IV: Blocks slow calcium channels

Correction of Conduction Defects, Bradycardias, and Tachycardias

Electronic Pacemaker:
- Temporary
- Permanent
Cardioversion:
- Defibrillation
- Synchronized
Ablation: Surgical interventions

Radiofrequency Ablation

Cardioversion

Elective procedures: Client awake & frequently sedated
Synchronization with QRS—50-200 Joules
EKG monitor & consent form

Defibrillation

Emergency procedures for V-fib & V-tach
No cardiac output—Start with 200 Joules, up to 360 Joules
Client unconscious & EKG monitoring

Question #2

Correct answer: C. The sinus node directly stimulates the rest of the heart into a new rhythm, having a greater effect than atrial arrhythmias.

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Description

Test your knowledge on cardiac conduction systems and rhythm disorders. This quiz covers the generation of electrical impulses, electrocardiography techniques, and heart rate calculations. Perfect for students and professionals in the medical field.