Cardiac Rhythms Pt 2

Question 1

causes of sinus tachycardia

Answer 1

Stress, exercise, fever, pain, meds, metabolic demands, hypovolemia- can lead to decreased diastolic filling time, < SV and cardiac enlargement

Question 2

treatment of sinus tachycardia

Answer 2

Treat underlying problem, Beta blockers, Calcium Channel Blockers
Beta Blockers- Metoprolol or Labetolol
Calcium Channel Blockers- Diltiazem (Cardizem)
If rate continues to SVT- give adenocard, then cardizem

Question 3

causes of sinus bradycardia

Answer 3

Decreased automaticity of SA node, HB, dig toxicity, MI, Hyperkalemia
Decreased cardiac output, unable to maintain perfusion, if slows too much, allows other pacemaker cells to take over

Question 4

treatment of sinus bradycardia

Answer 4

Atropine- 1 mg IVP, may repeat q 3-5 min, to max of 0.4mg/kg
Pacemaker- must do if 2nd or 3rd degree HB, otherwise, treat the patient- what is their BP and perfusion
Avoid any suctioning, gag reflex

Question 5

describe the types of pacemakers

Answer 5

Temporary pacing—invasive and noninvasive

Permanent pacemakers

Question 6

causes of atrial tachycardia (SVT)

Answer 6

May have runs without problems, fever, stress, adrenergic meds, caffeine, hypertrophy of atrium, asthma
Leads to increased workload, < coronary bloodflow and < C.O.

Question 7

treatment of atrial tachycardia (SVT)

Answer 7

Adenosine (Adenocard)- 6mg IVP over 1-2 sec, may repeat with 12 mg, follow with NS flush
Diltiazem (Cardizem)- 0.25mg/kg IVP over 2 min; follow with infusion at 10mg/hr (1mg/1ml)
Carotid Massage
Cardioversion

Question 8

causes of atrial fib/flutter

Answer 8

CHF, LV failure, injury to SA node, catecholamine secretion
Flutter may be more dangerous, spontaneous and may lead to < filling, < SV and < C.O.
Fib- more chronic in nature, assess need for treatment by patient’s response- what is BP?, Cardiac output?

Question 9

treatment of atrial fib/flutter

Answer 9

Cardizem- bolus, usual 20 mg IVP, then infusion of 5-15 mg/hr for 24 hours
Digoxin- increases refractory period of AV node and slows V. rate- 0.5 mg-1mg loading dose over 24 hours
Amiodarone- 1mg/min for 6 hours, then 0.5mg/min for 18, only for emergent
Cardioversion
Anticoagulants, esp for A. fib

Question 10

causes of V-tach and V-fib

Answer 10

Myocardial irritability, M.I., ischemia, plaque formation, toxic irritation from drugs & chemical, mechanical irritation from leads, hypoxia and hypertrophy of ventricles
Pt first has angina, apprehension, then

Question 11

treatment of V-tach

Answer 11

Shock/Cardioversion
Epinephrine- 1mg IV q 3-5 min
Vasopressin- 40 U IV once if epi not effective
Amiodarone- 150mg IVP over 10 min, then begin infusion of 360mg over 6 hr & 540mg over 18 hrs.
If arrest- amiodarone is 300mg IVP in 20ml of D5W
Lidocaine- 100mg IVP then infusion of 1-4mg/min (15-60ml/hr), rarely used
Mag Sulfate if torsades- 25-50mg/kg over10-20 min (max of 2 gm)

Question 12

treatment of V-fib

Answer 12

defibrillation