ECG Normal Sinus Rhythm

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What is the normal heart rate in beats per minute?

100-120

120-140

40-60

60-100 (correct)

What is the duration of a normal PR interval?

0.20-0.25 second

0.05-0.10 second

0.12-0.20 second (correct)

0.10-0.15 second

What is the term used to describe an abnormal heart rhythm?

Tachycardia

Dysrhythmia

Cardiac arrest

Arrhythmia (correct)

What is the primary cause of sinus block?

Ischemia of the SA node (B) Signup and view all the answers

Which of the following is a cause of arrhythmias?

Myocardial ischemia (A) Signup and view all the answers

What should be treated in a patient with an arrhythmia?

The patient and their symptoms (C) Signup and view all the answers

What is the characteristic of the P waves in a sinus block?

Upright and normal in morphology (D) Signup and view all the answers

What is the treatment for an asymptomatic patient with sinus block?

Observation (A) Signup and view all the answers

What is the term for the absence of cardiac electrical activity?

Arrhythmia (B) Signup and view all the answers

What is the difference between sinus pause and sinus arrest?

Sinus pause is a single missed beat, while sinus arrest is multiple missed beats (A) Signup and view all the answers

What is the clinical significance of frequent or prolonged episodes of sinus block?

It can compromise cardiac output, resulting in syncope (C) Signup and view all the answers

What is sick sinus syndrome characterized by?

Wild swings in the heart rate (D) Signup and view all the answers

What is the pacemaker site in sick sinus syndrome?

SA node (A) Signup and view all the answers

What is the normal PR interval in sick sinus syndrome?

Normal (B) Signup and view all the answers

What is the treatment for sinus pause or sinus block if atropine fails?

Transcutaneous pacing or a catecholamine infusion (D) Signup and view all the answers

What is the danger of complete cessation of SA node activity?

Cardiac standstill (D) Signup and view all the answers

What is the primary concern when the SA node activity ceases completely?

Cardiac standstill (A) Signup and view all the answers

What is the primary focus when treating a patient with cardiac arrhythmias?

The patient (A) Signup and view all the answers

What is the treatment for a patient with signs of poor perfusion due to SA node dysfunction?

Transcutaneous pacing or catecholamine infusion (C) Signup and view all the answers

What is the normal direction of depolarization impulse transmission through the conductive system and myocardium?

Antegrade (A) Signup and view all the answers

What is the characteristic of a wandering atrial pacemaker in terms of pacemaker site?

Varies among the SA node, atrial tissue, and the AV junction (D) Signup and view all the answers

What is the result of enhanced automaticity in the heart?

Ectopic beats (A) Signup and view all the answers

What is the term for a heart cell that is not a pacemaker cell?

Ectopic focus (B) Signup and view all the answers

What is the significance of a wandering atrial pacemaker?

It usually has no detrimental effects (A) Signup and view all the answers

What type of arrhythmia is characterized by a rapid heart rate?

Tachyarrhythmia (B) Signup and view all the answers

What is the definition of multifocal atrial tachycardia (MAT)?

A wandering pacemaker rhythm with a rate more than 100 (C) Signup and view all the answers

What is the common underlying condition in patients with multifocal atrial tachycardia?

Pulmonary disease (D) Signup and view all the answers

What is the term for the classification of arrhythmias based on the site of origin?

Site of origin (D) Signup and view all the answers

What is the characteristic of premature atrial contractions (PACs) in terms of P wave morphology?

Different P wave morphology for each beat (A) Signup and view all the answers

What is the term for a slowing of the SA node?

Sinus bradycardia (B) Signup and view all the answers

What is the cause of a noncompensatory pause in the underlying rhythm in PACs?

Depolarization of the atrial syncytium (D) Signup and view all the answers

What is the normal heart rate range for sinus bradycardia?

Less than 60 beats per minute (B) Signup and view all the answers

What is the treatment for patients with multifocal atrial tachycardia?

Underlying medical disease treatment (C) Signup and view all the answers

What is the primary treatment for sinus bradycardia?

No treatment unless signs of poor perfusion are present (C) Signup and view all the answers

What is the significance of multifocal atrial tachycardia?

It is a sign of a serious underlying medical illness (A) Signup and view all the answers

What is the purpose of administering atropine sulfate in sinus bradycardia?

To increase the heart rate (A) Signup and view all the answers

What is the primary cause of sinus tachycardia?

Increased rate of SA node discharge (A) Signup and view all the answers

Which of the following is a compensatory mechanism for decreased stroke volume?

Sinus tachycardia (C) Signup and view all the answers

What is the usual rate of sinus arrhythmia?

60-100 (C) Signup and view all the answers

What is the cause of sinus arrest?

Ischemia of the SA node (D) Signup and view all the answers

What is the characteristic of the RR interval following a sinus arrest?

It varies (A) Signup and view all the answers

What is the treatment for asymptomatic sinus arrest?

Only observation (C) Signup and view all the answers

What is the characteristic of the pause in sinus block?

It is a multiple of the previous RR interval (C) Signup and view all the answers

Which of the following is a normal variant, particularly in young and elderly people?

Sinus arrhythmia (D) Signup and view all the answers

What is the result of very rapid heart rates in diseased hearts?

Increased myocardial oxygen demand (D) Signup and view all the answers

Which of the following is a clinical significance of sinus tachycardia?

It is a compensatory mechanism for decreased stroke volume (B) Signup and view all the answers

What is the next step if the patient does not convert after 1 to 2 minutes of administering adenosine?

Administer a second bolus of 12 mg over 1 to 3 seconds (C) Signup and view all the answers

Why is it important to determine whether the arrhythmia is narrow-complex or wide-complex tachycardia?

Because the treatments are considerably different for the two arrhythmias (C) Signup and view all the answers

What is the purpose of looking at lead II or VI in ECG?

To determine whether the arrhythmia is narrow-complex or wide-complex tachycardia (B) Signup and view all the answers

What is the contraindication for DC countershock?

If you suspect digitalis toxicity as the cause of the PSVT (C) Signup and view all the answers

What is the energy level of the initial synchronized direct current countershock?

50 to 100 joules (A) Signup and view all the answers

What is the recommended action if the patient becomes unstable with a heart rate of more than 150 beats per minute?

Proceed with synchronized cardioversion (B) Signup and view all the answers

What is the characteristic of the P wave in a PAC?

It occurs earlier than the next expected P wave (B) Signup and view all the answers

What is the effect of paroxysmal supraventricular tachycardia on cardiac output?

It decreases cardiac output due to inadequate ventricular filling time (A) Signup and view all the answers

What is the PR interval of an ectopic focus near the AV node?

Less than 0.12 second (B) Signup and view all the answers

What is the significance of frequent PACs?

They can indicate organic heart disease (C) Signup and view all the answers

What is the characteristic of the QRS complex in a PAC?

It can be more than 0.12 second if the PAC is abnormally conducted (A) Signup and view all the answers

What is the effect of vagal maneuvers on PSVT?

They slow the heart rate (A) Signup and view all the answers

What is the rate of paroxysmal supraventricular tachycardia?

150-250 beats per minute (B) Signup and view all the answers

What is the characteristic of the P wave in PSVT?

It is buried in the preceding T wave (A) Signup and view all the answers

What is the treatment for asymptomatic PACs?

Only observation is required (A) Signup and view all the answers

What is the significance of PSVT in young patients with good cardiac reserves?

They can tolerate PSVT well for short periods (C) Signup and view all the answers