47 Questions
Which node serves as the pacemaker of the heart?
SA node
What does the P wave represent in a healthy adult's ECG?
Atrial contraction
What is the normal duration of the PR interval in a normal rhythm?
0.12-0.20 seconds
Which of the following is a characteristic of Supraventricular Tachycardia (SVT)?
It is a rapid heartbeat that develops when normal electrical impulses of the heart are disrupted.
Which of the following is a characteristic of Ventricular Tachycardia (Vtach)?
It is a rapid heartbeat that originates from the ventricles with a wide QRS complex.
Which of the following is a potential cause of dysrhythmias?
Increased potassium levels
Which class of drugs is used to decrease heart rates in atrial fibrillation and supraventricular tachycardia?
Class 4 - Calcium channel blockers
Which node does the electrical impulse travel to after leaving the sinus node?
Atrioventricular (AV) node
What is the normal duration of the PR interval in a normal rhythm?
0.12-0.20 seconds
What does the P wave represent in a healthy adult's ECG?
Electrical depolarization of the atria
What is the function of the SA node in a healthy heart?
It serves as the pacemaker of the heart
What is the ST segment interval?
Interval between ventricular depolarization and ventricular repolarization
What does the QRS complex represent in an ECG?
Ventricular depolarization
What is a potential cause of ectopic beats and irregular rhythm?
PACs (atrial dysrhythmias)
What is a characteristic of atrial dysrhythmias (PACs)?
Irregular rhythm
What is a characteristic of Ventricular Tachycardia (Vtach)?
Wide and bizarre QRS complex
In a normal rhythm, how should the ST segment appear on an ECG?
Flat and then peaks with the T wave
Which of the following is a characteristic of Ventricular Fibrillation (Vfib)?
It is a rapid heartbeat that originates from the ventricles.
Which of the following electrolyte imbalances can potentially cause dysrhythmias?
Hyperkalemia
Which class of drugs is aimed at delaying repolarization or blocking potassium (K+) channels?
Class 3
Which of the following drugs is a sodium channel blocker that decreases irritability in the ventricles?
Lidocaine
Which of the following is a nonpharmacological measure that is usually tried first before using antidysrhythmics?
Electrolyte replacement
Which of the following is a characteristic of Supraventricular Tachycardia (SVT)?
It is a rapid heartbeat that originates from the atria.
Which of the following drugs is a calcium channel blocker that slows AV node automaticity and delays AV node conduction?
Diltiazem
Which of the following is a characteristic of Bradyarrhythmia?
It is a slow heartbeat with a rate less than 60 beats per minute.
Which of the following is a characteristic of Ventricular Tachycardia (Vtach)?
It is a rapid heartbeat that originates from the ventricles.
Which of the following drugs is a beta blocker that decreases sympathetic nervous system activity and contributes to antidysrhythmic effects?
Propranolol
Which of the following represents ventricular depolarization?
QRS complex
What is the normal duration of the QRS complex in a normal rhythm?
0.08-0.10 seconds
Which of the following is a characteristic of atrial dysrhythmias (PACs)?
Abnormal P wave morphology
What does the ST segment interval represent on an ECG?
Interval between ventricular depolarization and ventricular repolarization
Which of the following drugs is a calcium channel blocker that slows AV node automaticity and delays AV node conduction?
Calcium channel blocker
Which of the following is a characteristic of ventricular dysrhythmias (PVCs)?
Wide and bizarre QRS complex
What is the normal duration of the PR interval in a normal rhythm?
0.12-0.20 seconds
Which of the following is a nonpharmacological measure that is usually tried first before using antidysrhythmics?
Vagal maneuvers
Which of the following is a potential cause of dysrhythmias?
Sympathetic nervous system activity
Which node does the electrical impulse travel to after leaving the sinus node?
AV node
Which of the following is a characteristic of Supraventricular Tachycardia (SVT)?
It is a rapid heartbeat that develops when normal electrical impulses of the heart are disrupted.
Which of the following drugs is a sodium channel blocker that decreases irritability in the ventricles?
Lidocaine
Which of the following is a potential cause of dysrhythmias?
All of the above
What is the function of the SA node in a healthy heart?
To coordinate the contraction of the atria
Which of the following drugs is a beta blocker that decreases sympathetic nervous system activity and contributes to antidysrhythmic effects?
Propranol
Which class of drugs is used to decrease heart rates in atrial fibrillation and supraventricular tachycardia?
Class 4
What does the QRS complex represent in an ECG?
Ventricular depolarization
Which node serves as the pacemaker of the heart?
SA node
What does the P wave represent in a healthy adult's ECG?
Atrial depolarization
Which class of drugs is aimed at delaying repolarization or blocking potassium (K+) channels?
Class 3
Study Notes
Heart Rhythm and ECG
- The SA (Sinoatrial) node serves as the pacemaker of the heart.
- The P wave represents atrial depolarization in a healthy adult's ECG.
- The normal duration of the PR interval in a normal rhythm is 0.12-0.20 seconds.
- The electrical impulse travels to the AV node after leaving the sinus node.
Dysrhythmias
- A potential cause of dysrhythmias is electrolyte imbalance.
- A characteristic of Supraventricular Tachycardia (SVT) is a rapid heart rate.
- A characteristic of Ventricular Tachycardia (Vtach) is a wide QRS complex with a rapid heart rate.
- A characteristic of Ventricular Fibrillation (Vfib) is a chaotic heart rhythm.
ECG Intervals
- The QRS complex represents ventricular depolarization in an ECG.
- The normal duration of the QRS complex in a normal rhythm is 0.08-0.12 seconds.
- The ST segment interval represents the period of ventricular repolarization in an ECG.
- In a normal rhythm, the ST segment should appear isoelectric (flat) on an ECG.
Antidysrhythmic Drugs
- Class I drugs, such as sodium channel blockers, decrease irritability in the ventricles.
- Class II drugs, such as beta blockers, decrease sympathetic nervous system activity and contribute to antidysrhythmic effects.
- Class III drugs, such as potassium channel blockers, delay repolarization or block potassium (K+) channels.
- Class IV drugs, such as calcium channel blockers, slow AV node automaticity and delay AV node conduction.
Nonpharmacological Measures
- A nonpharmacological measure that is usually tried first before using antidysrhythmics is vagal maneuvers.
Atrial Dysrhythmias
- A characteristic of atrial dysrhythmias (PACs) is premature atrial contractions.
- A characteristic of atrial dysrhythmias (PACs) is a P wave that is different from the normal P wave.
Ventricular Dysrhythmias
- A characteristic of ventricular dysrhythmias (PVCs) is premature ventricular contractions.
- A characteristic of ventricular dysrhythmias (PVCs) is a wide QRS complex that is different from the normal QRS complex.
Test your knowledge of the electrical conduction pathway of the heart with this quiz. Learn about the role of the sinus node, AV node, Bundle of HIS, and more in maintaining a healthy heart rhythm. See if you can identify these key components on an ECG graph.
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