Review Question - QID 109842

Antiarrhythmics Introduction Ventricular Arrhythmias Type Electrocardiogram Findings Treatment Ventricular premature beats (VPBs) Widened QRS complex with abnormal morphology Typically with reassurance or a β-blocker in healthy patients Ventricular tachycardia QID: 109842 (M2.CV.17.4869)

QID 109842 (Type "109842" in App Search)

A 59-year-old man presents to the emergency department with chest pain. He felt a strange sensation in his chest which started after he ate dinner. The patient has a medical history of obesity, diabetes, and alcoholism. His current medications include atorvastatin, lisinopril, metformin, and insulin. His temperature is 99.5°F (37.5°C), blood pressure is 90/58 mmHg, pulse is 120/min, respirations are 17/min, and oxygen saturation is 98% on room air. On physical exam, the patient appears comfortable. Cardiac exam reveals tachycardia. Pulmonary and abdominal exams are within normal limits. An ECG is performed as seen in Figure A. An initial set of cardiac troponins are negative. Which of the following is associated with the most appropriate next step in management?

Type & Select Correct Answer

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Bronchospasm

3/56

Hyporeflexia

39%

22/56

Pulmonary fibrosis with long-term use

4/56

Transient heart block

12%

7/56

Unsynchronized electrical current

36%

20/56

Select Answer to see Preferred Response

This patient is presenting with stable ventricular tachycardia (VT) which should be managed with chemical cardioversion. Amiodarone is an appropriate agent which has a side effect of pulmonary fibrosis if used as a long-term medication.

Ventricular tachycardia presents with wide monomorphic waves on ECG. Patients without a pulse should receive defibrillation. Hypotensive patients who do have a pulse can receive synchronized cardioversion to attempt rhythm conversion. Patients with a normal blood pressure (or borderline low blood pressure) should receive chemical cardioversion for which amiodarone is the preferred agent. Side effects of amiodarone include pulmonary fibrosis if used chronically. There are many other possible side-effects with chronic use including hypothyroidism and retinal deposits.

Foerster et al. review the evidence regarding the diagnosis and treatment of patients with ventricular tachycardia. They discuss how amiodarone can be used in a safe and effective manner for this disease. They recommend comparing amiodarone with procainamide for use during this disease.

Figure/Illustration A is an ECG demonstrating wide monomorphic QRS complexes (red circle). Note that there is also a rapid rate and absence of P waves indicating ventricular tachycardia.

Incorrect Answers:
Answer 1: Bronchospasm describes a side effect of beta blockers. Beta-blockers could potentially worsen this patient's blood pressure. Beta-blockers could be used for supraventricular tachycardia.

Answer 3: Hyporeflexia could be seen with magnesium sulfate drips. Magnesium sulfate drips can be used for atrial fibrillation with rapid ventricular response and atrial flutter. Magnesium can be given in ventricular tachycardia but is not a primary treatment.

Answer 4: Transient heart block describes the mechanism of action of adenosine. Adenosine would be indicated in the management of supraventricular tachycardia which presents with a narrow-complex tachycardia. Flushing is another possible side-effect.

Answer 5: Unsynchronized electrical current describes defibrillation, which would be administered in a patient with pulseless VT. This patient has a pulse with a stable blood pressure so chemical cardioversion should be used first. Defibrillation in a patient with a pulse could deliver a shock during ventricular repolarization resulting in cardiac arrest (thus why it should not be used in this situation).

Bullet Summary:
Stable ventricular tachycardia should be treated with chemical cardioversion using agents such as amiodarone (can cause pulmonary fibrosis with long-term use).