Ventricular Arrhythmias (Exam 2 Cut Off)

Question 1

Sinus Bradycardia

Answer 1

• Sinus rate < 60/min
• Determine if clinically significant
• Treat precipitating factors
• Physiologic: athletes, valsalva maneuver
• Pharmacologic: B-blockers, CCB, amiodarone
• Pathologic: Acute MI (especially inferior MI), hypothermia, HTN

Question 2

Sinus Bradycardia Prognosis/Treatment

Answer 2

• Rates 50-60 usually well tolerated, don’t need to treat
• Rates <40 may produce hypotension, confusion, syncope
• Treatment: atropine, artificial pacemaker

Question 3

Sinus Tachycardia

Answer 3

• Rate > ~80-100/min
• Physiologic: infancy, exercise, stress
• Pharmacologic: sympathomimetics, anticholinergics, xanthines
• Pathologic: Severe anemia, hypovolemia, hypotension, fever (10 beats/min per F rise), hyperthyroidism, hypoxia, CHF

Question 4

Sinus Tachycardia Prognosis/Treatment

Answer 4

• Rates below 100 w/o CVD usually not critical
• WITH CVD we prefer HR at 70 or under (decreases myocardial oxygen demand)
• Rates over 140 might compromise cardiac output and increase oxygen consumption enough to cause angina
• Treatment: Correct underlying cause, beta blockade

Question 5

AV/AV-Nodal Re-entrant Tachycardias

Answer 5

• Symptoms: Palpitations, dizziness, dyspnea, chest pain, fatigue, syncope
• Several treatment options (check treatment flowchart)

Question 6

AV/AV-Nodal Re-entrant Treatmenst

Answer 6

• Type I AA: act primarily on retrograde fast pathway (can also consider amiodarone or sotalol)
• Digoxin + B-blockers: act on fast or slow antegrade pathway
• Diltiazem, verapamil, and adenosine (6-12 mg IV): act mainly on slow pathway to prolong conduction time and increase refractoriness
• DCC: use if severely symptomatic (syncope, chest pain, severe HF)
• Nonpharm: utilized in mild-mod symptom patients: carotid sinus massage, valsalva maneuver, ice-water facial immersion (cholinergic stimulation can create two-way block in reentry circuit)

Question 7

WPW Syndrome

Answer 7

• Symptoms: palpitations, dizziness, dyspnea, chest pain, fatigue, syncope
• Most patients have accessory pathway ablated
• Flecainide, propafenone, amiodarone, dofetilide, sotalol
• AV blocking drugs must be used with caution or avoided in patients with associated Afib
• Using AV blocking drugs in those causes may cause rapid VRR with Afib (300-500 beats/min)

Question 8

1st Degree AV Block

Answer 8

• PR > 0.2 sec (implies AV nodal disease)
• Etiology: drug induced, hyperkalemia, hypoxia, CAD, MI (inferior)
• Causer Drugs: digoxin, verapamil, diltiazem, B-blockers, amiodarone
• Prognosis: benign, don’t treat

Question 9

2nd Degree AV Block

Answer 9

• Two types: Mobitz Type I and II

- Treatment: ONLY if symptomatic, acutely with atropine and long term with pacemaker

Question 10

3rd Degree AV Block

Answer 10

• No atrial depolarizations reaches ventricle
• Ventricular pacemakers take over (junctional escape, rhythm 30-60 beats/min)
• Usually VERY symptomatic: loss of consciousness
• Treatment: Pacemaker

Question 11

PVCs

Answer 11

• Premature ventricular contraction

- W/O heart disease: usually asymptomatic, do not require treatment unless bothersome (use B-blockers or IC agents)

Question 12

Ventricular Tachycardias

Answer 12

• Symptoms of VT if prolonged can vary form asymptomatic to pulseless (hemodynamic collapse)
• Fast heart rates with poor LV fxn with result in more severe symptoms
• Etiology: ischemia (post MI), electrolyte disturbances (hypokalemia), structural heart disease (HF), catecholamines, digitalis toxicity

Question 13

Sustained VT

Answer 13

• Lasts longer than 30 seconds
• Symptomatic
• Hemodynamics compromised
• Life threatening
• Can progress to V-fib

Question 14

Unsustained VT

Answer 14

• Brief and self-limiting, < 30 seconds
• Asymptomatic
• When present with CAD and LV dysfxn, can be at risk for sudden death, especially if symptomatic
• Treatment: none if no underlying heart disease, ICD placement and amiodarone secondarily if underlying disease
• Electrical ICD is most effective therapy