Section 10: UW and KM

Question 1

Best initial Rx for persistent sinus bradycardia with hemodynamic instability

Answer 1

• Intravenous atropine
• Temporary transvenous cardiac pacing

Question 2

Recommendations for anticoagulation for mechanical valves (ACC/AHA)

1. AVR with bileaflet mechanical valve, provided that the patient is in sinus rhythm, the left atrium is of normal size, and the left ventricular ejection fraction is normal
2. MVR with bileaflet mechanical valve
3. AVR with bileaflet mechanical valve in a patient with atrial fibrillation
4. Mechanical prosthetic valves in a patient who suffers a systemic embolism despite adequate anticoagulation

Answer 2

1. INR goal of 2.5 (range 2 to 3)
2. INR goal of 3 (range 2.5 to 3.5)
3. INR goal of 3 (range 2.5 to 3.5)
4. INR goal of 3 (range 2.5 to 3.5) + low dose aspirin

Question 3

Best initial management of acute aortic dissection

Answer 3

Intravenous beta-blockers (labetalol or propranolol)

Note: Sodium nitroprusside should not be used alone for blood pressure control without prior beta blockade

Question 4

A 28-year-old Mexican American woman comes to the emergency room because of palpitations. She has no other medical problems. She does not use tobacco, alcohol, or drugs. She takes no medications. Her temperature is 36.7^oC (98^oF), blood pressure is 100/60 mmHg, pulse 172/min, and respirations are 20/min. A 12-lead EKG is taken, which shows a heart rate of 172 beats/min with no P waves, and with regular and narrow-appearing QRS complexes.

Which of the following is the most likely diagnosis?

• A. Atrial fibrillation
• B. Ventricular tachycardia
• C. Sinus tachycardia
• D. Paroxysmal supraventricular tachycardia
• E. Atrial flutter

Source: UW

Answer 4

D. The patient’s EKG findings () archaracteristic of a paroxysmal supraventricular tachycardia (SVT). SVT includes such common entities as AV nodal reentrant tachycardia. The term “paroxysmal SVT” excludes atrial fibrillation and atrial flutter, other common forms of supraventricular arrhythmias

Question 5

A 28-year-old Mexican American woman comes to the emergency room because of palpitations. She has no other medical problems. She does not use tobacco, alcohol, or drugs. She takes no medications. Her temperature is 36.7^oC (98^oF), blood pressure is 100/60 mmHg, pulse 172/min, and respirations are 20/min. A 12-lead EKG is taken, which shows a heart rate of 172 beats/min with no P waves, and with regular and narrow-appearing QRS complexes.

The patient receives antiarrhythmic therapy, and her heart rate decreases from 172/min to 68/min. The palpitations resolve, and the patient begin to feel better. A new 12-lead EKG is taken, which shows a heart rate of 70/min, regular rhythm, presence of P waves, a PR interval of 0.10 sec, a slurred initial part of activation of the QRS complex, a QRS of 0.12 sec, and nonspecific T wave abnormalities. Which of the following is the most likely diagnosis?

• A. Mahaim tachycardia
• B. Wolff-Parkinson White (WPW) syndrome
• C. Dual AV nodal pathways
• D. James fibers preexcitation
• E. Right bundle branch block

Answer 5

B. WPW syndrome. The slurred upstroke of the QRS complex during the initial part or ventricular activation is known as the delta wave. QRS duration is generally equal to 0.12 sec, but may have greater values. Another feature of WPW syndrome is a PR interval less than 0.12 sec

Question 6

Rx of choice for Wolff-Parkinson White syndrome in patients with symptomatic arrhythmias

Answer 6

Catheter-ablation therapy