Chapter 5

Question 1

Sinus Bradycardia

Answer 1

Characteristics:

Heart rate below 60 bpm

Clinical significance:

Syncope, chest pain, premature beats, ventricular tachycardia.

Normal in athletes; mostly benign

Management:

No treatment necessary if asymptomatic and heart rate close to 60 bpm

Atropine if heart rate < 40 bpm

Installation of temporary or permanent pacemaker

Question 1

Inappropriate sinus tachycardia (IST)

Answer 1

No identifiable underlying factor causing tachyarrhythmia

Symptoms can be seen after viral illness

Recovery in 9-12 months

Symptomatic patient treatment: maintaining hydration and beta-blockers

Question 3

Normal sinus rhythm

Answer 3

Characteristics:

impulse originates in SA node and proceeds to AV node. Progresses down ventricles through normal pathways resulting in normal P and QRS complex.

Question 4

Sinus Tachycardia

Answer 4

Characteristics:

Heart rate > 100 bpm

Involves accelarated firing of SA node

Clinical significance:

Commonly considered symptom of an underlying pathophysiologic process

Treatment:

identify and treat underlying cause

Adenosine or digoxin

Question 5

Sinus Arrhythmia

Answer 5

Characteristics:

Normal heart rate with irregular rhythm

Commonly seen in athletes, children, and patients with sleep apnea

Result of vagal control over heart

Waxing and Waning of heart rate in response to respiration.

Clinical and management:

No pathophysiologic significant and no treatment

Question 6

Sinus Arrest

Answer 6

Characteristics:

Prolonged failure of SA node to initiate impulse

Complete missing of PQRST complex

Clinical significance:

Most common causes: ischemia affecting SA node

excessive vagal tone

asymptomatic for shorter pauses, longer pauses create hemodynamic compromise

Management:

Depends on underlying causes; same as bradycardia