Heart Block And Alternate Rhythms

Question 1

Chronotropic incompetence

Answer 1

Failure of the intrinsic rate response which regulates heart rates
Ie- when a patient exercises their heart rate does not increase. - thus they have chronotropic incompetence

Question 2

Causes of Sinus Node Dysfunction

Answer 2

*idiopathic SA node fibrosis
Drugs, excessive vagal tone
Ischemic, inflammatory, infiltrative disorders
Noted as a condition of deteriorating conduction system (age, underlying cardiac disorders, diabetes)
Can be aggravated by medication

Question 3

Exit block vs Sinus Pause

Answer 3

Exit block - SA node block (First, Second I & II, Third)
Sinus pause- temp absence of SA node activity usually lasting for seconds, an escape beat or rhythm may be generated if the pause is long enough.

Question 4

Sinus Arrest (sinus Pause)

Answer 4

SA node ceases generating impulses

• no sinus activation
• normal sinus beat post pause
• length of pause not a multiple of missed beats

Question 5

Tachy-Brady Syndrom (sick sinus syndrome)

Answer 5

Alternating of rapid and slow rhythms, often accompanied by pauses. Most often occurs during Afib, but may be seen in sinus rhythm.

Question 6

Symptoms of tachy- brady

Answer 6

Dyspnea
Syncope or presyncope
Palpitations
Lightheaded/dizzy
SOB
Fatigue
Nausea
Headache

Question 7

Causes of Afib

Answer 7

Metabolic disorders
Atrial dilation
Ischemia
Hypertensive disease
Heart failure
Mitral valve stenosis