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Questions and Answers
An electrical wave moving in the direction of a positive electrode will:
An electrical wave moving in the direction of a positive electrode will:
- Manifest with narrow QRS complexes.
- Cause a positive deflection on the ECG. (correct)
- Cause a negative deflection on the ECG.
- Produce a significant amount of artifact.
Depolarization, the process by which muscle fibers are stimulated to contract, occurs when:
Depolarization, the process by which muscle fibers are stimulated to contract, occurs when:
- Cell wall permeability changes and sodium rushes into the cell. (correct)
- Potassium ions escape from the cell through specialized channels.
- Calcium ions rapidly enter the cell, facilitating contraction.
- Cardiac muscle relaxes in response to a cellular influx of calcium.
Atrial fibrillation can be interpreted by noting:
Atrial fibrillation can be interpreted by noting:
- An irregularly irregular rhythm and absent P waves. (correct)
- PR intervals that vary from complex to complex.
- A regular rhythm with abnormal P waves.
- The presence of wide QRS complexes and a rapid rate.
Which of the following statements regarding the SA node is correct?
Which of the following statements regarding the SA node is correct?
The P wave represents:
The P wave represents:
A classic sign of atrial flutter is:
A classic sign of atrial flutter is:
The AV junction:
The AV junction:
Changes in cardiac contractility may be induced by medications that have a positive or negative ___________ effect.
Changes in cardiac contractility may be induced by medications that have a positive or negative ___________ effect.
Automaticity is defined as the ability of the heart to:
Automaticity is defined as the ability of the heart to:
Sinus dysrhythmia is:
Sinus dysrhythmia is:
A 'run' of ventricular tachycardia occurs if at least ____ PVCs occur in a row.
A 'run' of ventricular tachycardia occurs if at least ____ PVCs occur in a row.
Ventricular bigeminy occurs when:
Ventricular bigeminy occurs when:
Patients with a heart rate greater than 150 beats/min usually become unstable because of:
Patients with a heart rate greater than 150 beats/min usually become unstable because of:
The layers of the wall of the heart, beginning with the outermost layer, are the:
The layers of the wall of the heart, beginning with the outermost layer, are the:
Study Notes
Cardiac Electrical Activity and Arrhythmias
- An electrical wave toward a positive electrode causes a positive deflection on the ECG.
- Depolarization in muscle fibers is triggered when sodium rushes into the cell due to changes in cell wall permeability.
- Atrial fibrillation is characterized by an irregularly irregular rhythm and absent P waves.
Sinoatrial (SA) Node and Atrial Activity
- The SA node serves as the dominant cardiac pacemaker in healthy individuals.
- The P wave on an ECG signifies atrial depolarization.
- Atrial flutter is identified by sawtooth P waves.
Atrioventricular (AV) Junction
- The AV junction consists of the AV node and surrounding tissue.
- Changes in cardiac contractility are influenced by inotropic medications.
Heart Function and Rhythms
- Automaticity is the heart's ability to generate its own electrical impulses without neural stimulation.
- Sinus dysrhythmia is recognized as an irregular sinus rhythm.
- A run of ventricular tachycardia is defined as three or more consecutive PVCs.
- Ventricular bigeminy occurs when every second complex is a PVC.
Complications from High Heart Rate
- Heart rates exceeding 150 beats/min typically lead to instability due to reduced ventricular filling.
Heart Wall Structure
- The outermost layer of the heart wall is the epicardium, followed by the myocardium, and the innermost layer is the endocardium.
Idioventricular Rhythm
- Idioventricular rhythms can lead to hemodynamic instability and are often associated with nonconducted P waves.
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Test your knowledge on electrophysiology with these flashcards from Quiz 2.2. Each question focuses on key concepts related to electrical waves and muscle fiber depolarization in the context of ECG interpretation. Perfect for students and professionals alike!
